Infectious Disease

Question 1

4 week history of painless mass of jaw; sinus formation

Answer 1

Actinomyces israelii

Question 2

A 19-year-old woman visits her physician for a preventive health examination. Her medical history is unremarkable. She is sexually active with her boyfriend, and they use condoms inconsistently. She had one prior sexual partner and reports no symptoms of vaginal infections or sexually transmitted diseases. Results from her gynecologic examination are normal. Should this woman be screened for chlamydia, and if so, how?

Answer 2

• screening via self-collected vaginal swab or endocervical swab - use nucleic acid amplification assays Alternatively: first-catch urine Testing of a urine sample has slightly lower sensitivity

Question 3

a 42 year old asymptomatic man with hypertension. Meds: atenolol + chlorthalidone FH: type 2 diabetes mellitus later in life. Does not smoke cigarettes. BMI: 32.3, BP: 130/80 mm Hg. Would you screen the patient for diabetes, and if so, how?

Answer 3

• Whether fasting glucose or A1C measured remains debatable - Sensitivity higher when both tests are performed, I typically assess both simultaneously — although most guidelines suggest the use of a single test initially. - If the patient has positive results on both tests, the diagnosis is confirmed. - If only one test is positive, I would repeat it on a separate day.

Question 4

Acute bronchitis groups: What differentiates groups 1, 2 and 3 from each other?

Answer 4

Group 1: No risk factors

Group 2: > 1 of the following:

1. FEV1 <50% predicted
2. >4 exacerbations/yr
3. Cardiac disease
4. Use of home O2
5. Chronically on prednisone
6. Antibiotic use in past 3 mo

Group 3: symptoms as in group 2 + one of

1. constant purulent sputum
2. bronchiectasis
3. FEV1 <35% predicted
4. Multiple risk factors from Group 2

Question 5

Acute epiglottitis: Empiric Abx

Answer 5

Ceftriaxone + Vancomycine

Question 6

Acute epiglottitis+stridor: Rx

Answer 6

Awake fiberoptic Nasotracheal intubation

Question 7

hearing loss that occurs acutely, usually within 12 hours of onset, and is unilateral in 90 percent of cases. The hearing loss may occur suddenly, be found on awakening, or may be rapidly progressive over hours (or perhaps over two to three days).

Answer 7

Sudden sensorineural hearing loss (SSNHL)

Many etiologies for SSNHL; however, for many cases, cause is not known.

Most : viral cochleitis, a microvascular event, or an autoimmune process.

Spontaneous improvement is common

Studies are contradictory on the effectiveness of glucocorticoid therapy.

Rx: 10- to 14-day prednisone, 60 per day

Intratympanic glucocorticoids may be used as initial therapy if intolerant to PO steroids.

Subset of patients with SSNHL may have HSV-I infection and could benefit from antiviral drug

Question 8

The rapid expansion of HIV-1, first in _-_ _ _ and then systemically, along with a sharp rise in plasma levels of viral RNA, is clinically important because of the irreversible destruction of reservoirs of _ _ cells and the establishment of viral latency (defined as the _ _ of HIV-1 DNA into the _ of resting T cells, an effect that has stymied curative treatment efforts.

Answer 8

The rapid expansion of HIV-1, first in gut-associated lymphoid tissue and then systemically, along with a sharp rise in plasma levels of viral RNA, is clinically important because of the irreversible destruction of reservoirs of helper T cells and the establishment of viral latency (defined as the silent integration of HIV-1 DNA into the genomes of resting T cells, an effect that has stymied curative treatment efforts.

Question 9

Acute onset of fever, myalgia, maculopapular rash, pharyngitis, aseptic meningitis: Dx

Answer 9

Acute HIV

Question 10

Acute prostatitis: Rx

Answer 10

Ceftriaxone, quinolone, Bactrim for 2 weeks

Question 11

acute viral or postviral inflammatory disorder of the vestibular portion of the eighth cranial nerve.

Answer 11

Vestibular neuritis

Presents: acute vertigo with nausea, vomiting, and gait impairment.

Differential: includes brainstem, cerebellar stroke.

No confirmatory test for vestibular neuritis.

Prednisone taper

vestibular suppressants and antiemetics to limit symptoms in the first 24 to 48 hours (Grade 2C).

Stop acute symptomatic treatments within 48 hours if the patient’s symptoms allow (Grade 2C). Some data suggest that these medications interfere with central compensation and long-term recovery.

Vestibular rehabilitation program after acute symptoms subside

Question 12

AFB Smear sensitivity, specificity

Answer 12

1. Sensitivity: 40-60%,
2. Specificity:90%
3. PPV: 50-80%

Question 13

All GABHS strains remain _ sensitive

Answer 13

penicillin

Question 14

All sexually active women younger than _ years of age as well as older women at risk for chlamydia should be offered chlamydia screening _.

Answer 14

All sexually active women younger than 25 years of age as well as older women at risk for chlamydia should be offered chlamydia screening annually

Question 15

angiofollicular lymph node hyperplasia, Rx

Answer 15

Castleman’s disease

1. HIV/HHV-8 negative, no organ failure: Immunotherapy (monoclonal antibody Rx)
2. HIV/HHV-8 negative, indication of aggressive disease: R-CHOP
3. HIV/HHV-8 positive: ganciclovir + rituximab, + etoposide if more aggressive disease

Question 16

Antibacterial resistance among these organisms is increasingly common (>_% of H. influenzae and _% of M. catarrhalis are now β-lactamase producers, meaning they are resistant to amoxicillin);

Answer 16

40, 100

Question 17

Antibiotic choices based on acute bronchitis categories

Answer 17

1. G1: 2nd Macrolides, 2nd gen ceph., Bactrim, Amoxicillin, Doxy
2. G2: Fluorquinolone, ß-lactam/β-lactamase inhibitor
3. G3: Cipro to cover Pseudomonas

Question 18

Significance

Answer 18

Risk of pandemic

Example of trigger

Question 19

Atypical pneumonia: bacteria

Answer 19

Mycoplasma, Legionella,Chlamydia

Question 20

Antigens? Why is it a cause of concern?

Answer 20

H5N1

similarity to 1918 influenza virulence

Avian influenza (H5N1) is a concern because of similarity to 1918 influenza severity; however, few cases to date in humans with limited human-to-human transmissibility.

Question 21

Avoid Zanamavir in

Answer 21

COPD, asthma

COPD, asthma because it is inhaled; can cause bronchospasm

Question 22

Preferred agent in contact lens wearer

Answer 22

Ofloxacin 0.3% ophthalmic drops

Question 23

Bacterial conjunctivitis in contact lens wearers: cause of concern?

Answer 23

Higher rates of Pseudomonas infxn

Question 24

Bacterial conjunctivitis: etiology

Answer 24

Staph, Strep, Haemophilus

Question 25

BeforeChemo

Answer 25

Screen for Hepatitis B

Reactivation of Hepatitis B occurs in 10 to 15% of patients undergoing immunosuppressive or cancer chemotherapy.; particularly high dose steroids and rituximab.

Question 26

Why is it effective in the treatment of drug induced parkinsonism?

Answer 26

centrally acting anticholinergic, also blocks the reuptake of dopamine

Question 27

Both Chlamydia trachomatis and Chlamydia pneumoniae are Gram-_ , aerobic, intracellular pathogens. They are typically coccoid or rod-shaped.

Answer 27

Gram-negative

(or at least are classified as such, they are difficult to stain, but are more closely related to Gram-negative bacteria)

Question 28

Castleman’s disease

Answer 28

heterogenous group of lymphoproliferative disorders associated with HIV and HHV-8.

• two distinct diseases (unicentric and multicentric) with very different prognoses.

MCD: presents in the fifth to sixth decade of life with peripheral lymphadenopathy and systemic symptoms including fever, night sweats, weight loss, and fatigue

Question 29

Chancroid: Rx

Answer 29

Azithromycin or ceftriaxone or ciprofloxacin

Question 30

Chlamydia is caused by the gram-_ bacterium Chlamydia trachomatis and is the .

Answer 30

Chlamydia is caused by the gram-negative bacterium Chlamydia trachomatis and is the most common infection reported in the United States, with more than 1.5 million cases reported in 2015.1

Question 31

Chlamydia prophylaxis after sexual assault

Answer 31

azithromcyin

Question 32

Chronic prostatitis: Rx

Answer 32

Quinolone: 4-6 weeks

Bactrim: 6-12 weeks

Question 33

Chronic sinusitis is diagnosed after at least _ weeks of sinus symptoms and signs.

Answer 33

12

Question 34

Cirrhosis: pain management

Answer 34

acetaminophen in limited doses, avoid opioids.

Eg: Acetaminophen, 500 mg orally every 8 hours as needed

Question 35

Clinical presentation suggestive of Strep pharyngitis, negative rapid antigen test. Mx?

Answer 35

if (Throat_culture_positive): treat

Question 36

CNS TB: Rx duration

Answer 36

9-12 months

Question 37

Codeine: why is not effective in hepatic impairment?

Answer 37

Metabolized in the liver to morphine

so will not provide effective analgesia for patients with significant hepatic dysfunction.

Codeine should be avoided in patients with renal insufficiency: renally cleared

Question 38

Common cause of hearing loss in elderly

Answer 38

Cerumen impaction

Particularly in those who use hearing aids

Question 39

Commonest organism in COPD exacerbation (%)

Answer 39

H influenzae, ~ 22%

1. H. influenzae is most common cause (~22%), particularly in smokers
2. M. catarrhalis (9–15%)
3. S. pneumoniae (10–12%)
4. Pseudomonas aeruginosa or other gram-negative bacteria (up to 15%) - recent antibiotic use or hospitalizations or frequent flares

Question 40

Complicated UTI is defined clinically by the presence of one of the following factors:

1. immunosuppression
2. Instrumentation,
3. Stone or
4. abnormal structural or functional abnormality

Which three are missing?

Answer 40

pregnancy, diabetes, male sex,

Question 41

DDx influenza

Answer 41

Mycoplasma pneumoniae, adenoviruses, respiratory syncytial viruses, rhinoviruses, parainfluenza viruses, and Legionella spp

Question 42

DDx: epididymitis

Answer 42

Testicular torsion

Rule out by Doppler ultrasound

Question 43

Hyperactive delirium, hyperactivity and dilated pupils after surgery

Answer 43

Think of anticholinergic toxicity.

Question 44

Dengue Differential

Answer 44

1. influenza
2. measles
3. rubella
4. malaria
5. Zika virus
6. Yellow fever.

Question 45

Dengue: why should aspirin and NSAIDs be avoided?

Answer 45

Bleeding complications

Question 46

Pustular acral skin lesions + asymmetric migratory polyarthralgia. Which STD?

Answer 46

Disseminated Gonoccal Infection

1. dermatitis with petechial or pustular acral skin lesions,
2. tenosynovitis, and
3. asymmetrical migratory polyarthralgias

OR

Purulent arthritis without skin lesions

Question 47

Describe condyloma acuminata: causative organism

Answer 47

Exophytic verrucous white or pigmented lesions

HPV

Types 16, 18, 31, 33, and 35 have been strongly associated with cervical neoplasia. HPV types 6 and 11 are rarely associated with neoplasia but cause ~90% of warts

Question 48

Describe this rash which ocurred after amoxicillin was given for suspected Strep. pharyngitis. What is the diagnosis?

Answer 48

Generalized erythematous papular eruption

of infectious mononucleosis precipitated by oral penicillin intake.

(From Shah BR, Laude TA: Atlas of pediatric clinical diagnosis, Philadelphia, WB Saunders, 2000, Fig. 3-32.)

Question 49

Difference between DRESS and LCV

Answer 49

DRESS LCV Rash Morbiliform Purpura Location Diffuse Extremities sparing hands, feet

Question 50

Difference between RCA and failure modes and effects analysis

Answer 50

RCA is retrospective, FMA is prospective

RCA is a retrospective and systematic investigation of a specific near-miss or adverse event. The goal of a root cause analysis is to identify underlying system defects, known as root causes, that contributed to the adverse event or near-miss and to develop corrective actions for each root cause.

A failure modes and effects analysis (Answer A) is a prospective—not retrospective—systematic technique designed to identify the severity and likelihood of error-prone situations, known as failure modes, within a system and process. As a result of a failure modes and effects analysis, systems and processes can be improved before implementation of a new process

Question 51

Difference: LCR and PCR

Answer 51

LCR PCR Method Amplifies Probe Polymerizes nucleotides

PCR carries out the amplification by polymerizing nucleotides, LCR instead amplifies the nucleic acid used as the probe.

For each of the two DNA strands, two partial probes are ligated to form the actual one; thus, LCR uses two enzymes: a DNA polymerase (used for initial template amplification and then inactivated) and a thermostable DNA ligase.

Each cycle results in a doubling of the target nucleic acid molecule. A key advantage of LCR is greater specificity as compared to PCR.

Question 52

Differential GABS pharyngitis

Answer 52

EBV pharyngitis

Question 53

Differential malaria

Answer 53

Dengue

Question 54

Differentiate viral from GAS pharyngitis

Answer 54

GAS Viral Onset Sudden -- Cough - + Hoarseness - + Fever + - Abd sx + - Rash + - Ant adenop + - Conjunct - + Ulcers - +

Question 55

Disseminated histoplasma skin lesions localize to:

Answer 55

face, chest and upper arms

papules to plaques

Question 56

Dix-Hallpike

Answer 56

Nystagmus: beating upward and torsionally, with the upper poles of the eyes beating toward the ground

Question 57

DRESS vs TEN

Answer 57

1. TEN: mucocutaneous involvement
2. DRESS: eosinophilia

Question 58

Drug induced LCV: Leukocytoclastic vasculitis, sometimes referred to as hypersensitivity vasculitis, often presents _ to _ weeks after starting the offending agent.

Answer 58

Drug induced LCV: Leukocytoclastic vasculitis, sometimes referred to as hypersensitivity vasculitis, often presents 1 to 3 weeks after starting the offending agent.

Question 59

Drug induced Parkinsonism: Rx

Answer 59

Anticholinergics (benztropine) if the offending agent cannot be discontinued.

Question 60

Drug-susceptible TB: Rx

Answer 60

1. 2 months: INH + rifampin + pyrazinamide + ( ethambutol (commonly used) or streptomycin (not commonly used)
2. 4 months: INH + Rifampin

Question 61

DVT prophylaxis after hip surgery: oral alternative

Answer 61

Low dose Rivaroxaban: 10 mg daily, while in the hospital and extended after discharge for a total of 2 weeks

Question 62

HIV: eclipse phase lasts

Answer 62

7 to 21 days

Question 63

A 24-year-old heterosexual man with no prior history of sexually transmitted infections has been informed that a recent sexual partner has been diagnosed with gonorrhea. He is asymptomatic. On examination, there are no penile lesions or urethral discharge. Gram stain of a urethral swab is negative for gonorrhea and chlamydia. Urinalysis shows 0 to 1 white blood cell (WBC) per high-power field. A rapid plasma reagin (RPR) and a fluorescent treponemal antibody (FTA) test performed on the same visit are both positive, with an RPR titer of 1:32. Appropriate treatment includes

Answer 63

Benzathine penicillin weekly x 3

+

Ceftriaxone 250 mg x 1

+

Azithromycin 1 g po

Question 64

Epididymitis : cause

Answer 64

In men younger than 35 years,: N. gonorrhoeae (30%) or C. trachomatis (70%)

In men older than 35 years, non–sexually transmitted epididymitis is more commonly caused by gram-negative enteric organisms

Question 65

Epistaxis + warfarin

Answer 65

if INR is thereapeutic, do not stop warfarin

Patients with high blood pressure on admission need assessment by their general practitioner after discharge from hospital. Patient medication, especially anticoagulants, raise concerns in management; although a prospective study showed warfarin does not need to be stopped if its levels are within therapeutic range.23 Aspirin medication has been shown to be independently associated with epistaxis hospitalisation.24 However, cessation of aspirin therapy should be weighed up against thromboembolic complications and the time delay between stopping aspirin and the return of normal platelet function.

Question 66

Epistaxis: choice of packing

Answer 66

1. RhinoRocket
2. Merecel

Anterior nasal packing is used for epistaxis that originates in Kiesselbach’s area and is refractory to the above treatments. Traditional packing products consist of nondegradable materials, such as gauze coated with petroleum jelly, a sponge composed of hydroxylated polyvinyl acetate that expands when wet (Merocel, Medtronic), and an inflatable pack with hydrocolloid coating that remains in contact with mucosa after the center of the pack has been deflated and removed (Rapid Rhino, ArthroCare). These packs are left in place for 1 to 3 days before removal. In randomized, controlled trials, their use stopped bleeding in approximately 60 to 80% of cases refractory to vasoconstrictors and pressure.

Insertion and removal of these packs can result in mucosal trauma, which may lead to recurrent bleeding or pain. In a randomized trial comparing Merocel and Rapid Rhino, there was no significant difference in the rates at which epistaxis was controlled, but both patients and physicians found Rapid Rhino easier to insert and remove.

Question 67

Epistaxis: immediate Mx

Answer 67

1. Pinch nose for 15 minutes
2. Position: whatever is comfortable
3. Oxymetazoline locally
4. Avoid swallowing or aspirating blood

pinching the anterior aspect of the nose for 15 minutes, which provides tamponade for the anterior septal vessels. The patient should relax, if possible. The head position can be either forward or backward, whichever is more comfortable, but it is important for the patient to avoid swallowing or aspirating any blood that may be draining posteriorly into the pharynx.

A common mistake is for the patient to attempt to compress the area along the nasal bones. Pressure should be applied more distally by compressing the nasal ala against the septum. In addition to pressure, topical oxymetazoline spray may be useful. In one study, oxymetazoline spray stopped the bleeding in 65% of consecutive patients with epistaxis who were being seen in an emergency room.14

Question 68

Epistaxis: rationale for anterior pack only as first step

Answer 68

1. > 90% causes is in the anterior nasal septum
2. Easier
3. Less risk of damaging nasal septum

Question 69

are due to failure to perform tasks that are done in a routine or automatic fashion and are often related to failure of monitoring. Technique errors during procedures fit into this category, such as neglecting to replace the stylet into a lumbar puncture needle before removal, thereby increasing the risk of spinal headache.

Answer 69

Skill error

Question 70

Erythema multiforme vs SJS

Answer 70

EM: papular, target lesions, centripetal spread, no systemic fx

SJS: macular, centrifugal spread, + systemic fx

Question 71

Examination for condyloma acuminata should include

Answer 71

anoscopy, sigmoidoscopy, colposcopy, and/or vulvovaginal examination

Question 73

Filariasis is caused by _ transmitted by _ vectors; humans are definitive hosts.

Answer 73

Filariasis is caused by nematodes transmitted by mosquito vectors; humans are definitive hosts.

Question 74

Difference in organisms

Answer 74

Filaria: nematode

Malaria:protozoan

Question 75

First line rx for ABS?

Answer 75

amoxicillin

Question 76

Fitz-Hugh-Curtis: sensitivity for PID

Answer 76

10%

Right upper quadrant tenderness from perihepatitis (Fitz-Hugh–Curtis syndrome) is seen in 10%

Question 77

Fixed drug reaction

Answer 77

Recurs in the same locations upon reexposure

sulfonamides, antibiotics, nonsteroidal antiinflammatory drugs, analgesics, and hypnotics

solitary round to oval, dusky red to brown/black macules that may evolve into edematous plaques or bullae

• lips, genitalia, perianal area, and extremities.

- 30 minutes to 8 hours after drug

• resolve spontaneously in 7 to 10 days, leaving a persistent gray/brown or slate gray hyperpigmentation

Question 78

Fresh water exposure in sub-Saharan Africa followed by fevers and cough.

Answer 78

Schistosomiasis

Question 79

Fungal pulmonary infection + Mississipi valley

Answer 79

Histoplasmosis

Question 80

Painless papule or nodule erodes into beefy-red granulomatous ulcer with rolled edges. Spread of granulomas into the groin results in edema or pseudobuboes
Rare in the United States

Answer 80

Donovanosis or granuloma inguinale

Klebsiella granulomatis

Donovan bodies on biopsy

Rx: Doxycycline or trimethoprim-sulfamethoxazole
Treat at least 3 wk

Question 81

Painful ulcer
Tender inguinal adenopathy
Hallmark is suppurative adenopathy
Occurs in outbreaks

Answer 81

Chancroid

Question 82

Painless genital ulcer; painful inguinal lymphadenopathy (with groove sign); proctitis

Answer 82

Lymphogranuloma venereum

Chlamydia trachomatis serovar L1, L2, or L3

Question 83

Cluster of vesicles on erythematous base
Painful and pruritic
Dysuria
Tender lymphadenopathy

Answer 83

Genital Herpes

HSV-2 > HSV-1

Tzanck preparation, multinucleated giant cells

Acyclovir or famciclovir or valacyclovi

Question 84

Genital warts: Rx

Answer 84

Surgery, cryotherapy, or topical therapy with podophyllin, imiquimod, or trichloroacetic acid

Question 85

Gonorrhea: Rx

Answer 85

ceftriaxone + azithromycin

Question 86

Gonorrhea, Chlamydia: DxTrigger

Answer 86

Refer sexual partners

1. sexual partners in the last 60 days or
2. the last sexual partner

Question 87

Gonorrhea: alternative to cephalosporin

Answer 87

Azithromycin 2g

Azithromycin monotherapy at 2-g dosing is effective for both gonorrheal infections and chlamydial infections, but its use is limited by GI distress; this is the only available alternate agent if cephalosporins cannot be used to treat gonorrhea

Question 88

1. Incubation: _ to _ days
2. Symptoms: _ to _ days after exposure

Answer 88

1. Incubation: 3 to 7 days
2. Symptoms: 10 to 14 days after exposure

Question 89

Gonorrhea: Rx

Answer 89

A third-generation cephalosporin plus 1-g of oral azithromycin

intramuscular ceftriaxone has excellent activity against genital and extragenital infections; oral cephalosporins are approved alternate agents but these may have lower activity against pharyngeal gonorrhea

Question 90

Gram-+ve rods of medical importance

Answer 90

A. Aerobes:

• Bacillus anthracis*
• Bacillus cereus*

B. Anaerobes

1. Clostridium perfringens -Gas gangrene
2. Clostrium difficile -
3. Clostrium tetani Tetanus /lockjaw
4. Clostridium botulinum

II. Gram Positive Regular Non-Spore-forming Rods

Lactobacillus, Listeria, Erysipelothrix, Kurthia, Caryophanon, Bronchothrix, Renibacterium

Question 91

Describe the image

Answer 91

Gram negative intra-cellular diplococci

Gram stain of Neisseria gonorrhoeae in urethral exudate.

Uptodate

Question 92

Gram-negative.rod

+ pulmonary infiltrates, associated with cooling towers

Answer 92

Legionella pneumophilia

Question 93

A young man presents with intermittent epigastric discomfort, without weight loss or evidence of gastrointestinal bleeding.

No use of aspirin or nonsteroidal antiinflammatory drugs (NSAIDs). + Epigastric tenderness. A serologic test for Helicobacter pylori is positive

Treated with 10-day course of triple therapy (omeprazole, amoxicillin, and clarithromycin). Six weeks later, he returns with the same symptoms. How should his case be further evaluated and managed?

Answer 93

For both the breath and fecal antigen tests

1. stop taking PPIs 2 weeks before testing,
2. should stop tak- ing H2 receptor antagonists for 24 hours before testing
3. No antimicrobial agents for 4 weeks before testing, since these medications may suppress the infection and re- duce the sensitivity of testing.

Question 94

H pylori duodenal ulcer: Pathogenesis

Answer 94

1. Infection is preferentially in the antrum.
2. Causes inflammation which stimulates release of gastrin.
3. Gastrin stimulates acid secretion from fundus.
4. Acid damages duodenal mucosa, causing ulceration and gastric metaplasia.
5. The metaplastic mucosa becomes colonized by H. pylori

Question 95

H pylori infections associated with

Answer 95

1. Duodenal or gastric ulcers (1 to 10% )
2. Gastric cancer (in 0.1 to 3%)
3. MALT lymphoma (in <0.01%).

Question 96

H. pylori: non-endoscopic test with highest PPV, NPV and useful both before and after treatment?

Answer 96

Urea breath test

Question 97

H. pylori: Rx

Answer 97

PPI +clarithromycin + amoxicillin, each given twice per day for 7 to 14 days.

Metronidazole is used in place of amoxicillin if penicillin allergy.

Duration: 10 to 14 days in the United States and 7 days in Europe.

Question 98

H. pylori: Rx, failure of eradication after first try

Answer 98

(levofloxacin or rifabutin) + (PPI + amoxicillin),

has been associated with high rates of eradication

Question 99

Features of 2009 H1N1 pandemic

Answer 99

1. Similar to seasonal influenza
2. children and young adults > customary elderly populations;
3. increased mortality more often in those with comorbidities

Question 100

Hep B e antigen: significance

Answer 100

1. Marker of replication and infectivity in persistent infection
2. Risk factor for HCC

Question 101

Which is the first antigen to appear following Hep B infection and when?

Answer 101

HBsAg 4 to 10 weeks after infection

Note: less than 5% of exposures lead to infection

Question 102

Hepatitis B sAg +; core Ag negative; about to start chemo. Mx?

Answer 102

Entecavir

Antiivral prophylaxis is necessary

Question 103

Hepatitis B, acute infection: risk of liver failure, progression to chronic HBV

Answer 103

Risk liver failure: < 1 percent, and in immunocompetent adults, the likelihood of progression to chronic HBV infection is less than 5 percent.

Question 104

Hepatitis B, acute: DxCritera/Mx

Answer 104

HBsAg + HBcAb-IgM

Mx: supportive

1. DxCriteria acute HBV infection: hepatitis B surface antigen (HBsAg) and IgM antibody to hepatitis B core antigen.
2. For most patients, treatment is supportive.
3. Risk liver failure: < 1 percent, and in immunocompetent adults, the likelihood of progression to chronic HBV infection is less than 5 percent.
4. Preventive measures (eg, hepatitis B immune globulin and hepatitis B vaccine) should be administered to all household and sexual contacts who are not known to be immune.

Question 105

Complications of herpes include aseptic meningitis and

Answer 105

urinary retention

Question 106

Herpes genitalis: cause

Answer 106

HSV-1 ~75%

HSV-2 ~25%

Question 107

Herpes gladiotorum: Rx

Answer 107

HSV-1

Question 108

High-level pneumococcal resistance to penicillin accounts for approximately _% of isolates in the United States.

Answer 108

4

Question 109

Histoplasmosis: Rx

Answer 109

Amphotericin B

Question 110

Histoplasma: biology

Answer 110

Dimorphic fungus

Ohio River Valley/

Question 111

Why are they at 100x risk for SJS/TEN?

Answer 111

1. alterations in drug metabolism
2. epidermal immune dysregulation

that occurs with HIV infection.

Question 112

Which of the following diagnostic test is most useful to detect herpes simplex virus type 2 (HSV-2) infection in a patient with recurrent genital ulcers who does not have active lesions at the time of presentation to the clinic?

1. Culture
2. Detection of antigen
3. Tzanck smear
4. Glycoprotein G–based serologic testing

Answer 112

Glycoprotein G–based serologic testing

Question 113

human antibodies capable of binding to animal immunoglobulins and possibly of interfering with reaction of animal-derived antibodies and analyte.

Answer 113

Heterophile antibodies

Heterophile antibodies are produced in response to infectious mononucleosis. These are not directed against EBV but agglutinate either horse or sheep RBCs occurs in 90% of cases and is detected by Monospot.

Question 114

IGFRA Tests and BCG vaccination

Answer 114

BCG vaccination has no effect.

Unlike TST where prior BCG will cause a false positive

Question 115

Importance of differentiating different groups in acute bronchitis

Answer 115

Bacteriology changes

1. Group 1: H influenzae, M catarrhalis, S pneumoniae
2. Group 2: G1 + Klebsiella + Gram negs + higher prob of ß-lactam resitant organism
3. Group 3: G1 + P aeruginosa + drug resistant Enterobacter

Question 116

Indications for daptomycin

Answer 116

1. Vancomycin intolerance or allergy
2. High vancomycin MIC

Question 117

Infectious cause of stroke

Answer 117

Late neurosyphilis, occurring many years after primary infection, may be meningovascular (presenting as stroke) or parenchymatous, manifesting as tabes dorsalis (electrical pains shooting down the legs) or general paresis (personality changes, hallucinations)

Question 118

Infectious causes of acute pharyngitis

Answer 118

Organism Clinical Manifestations

Viruses

Rhinovirus Common cold

Coronavirus Common cold

Adenovirus Pharyngoconjunctival fever I

nfluenza virus Influenza

Parainfluenza virus Cold, croup

Coxsackievirus Herpangina, hand–foot–mouth disease

Herpes simplex virus Gingivostomatitis (primary infection) Epstein–Barr virus Infectious mononucleosis

Cytomegalovirus Mononucleosis-like syndrome

Human immunodeficiency virus Acute (primary) infection syndrome

Bacteria

Group A streptococci Pharyngitis, scarlet fever

Group C and group G streptococci Pharyngitis

Mixed anaerobes Vincent’s angina (necrotizing gingivostomatitis)

Fusobacterium necrophorum Lemierre’s syndrome (septic thrombophlebitis of the internal jugular vein)

Arcanobacterium haemolyticum Pharyngitis, scarlatiniform rash

Neisseria gonorrhoeae Pharyngitis

Treponema pallidum Secondary syphilis

Francisella tularensis Pharyngeal tularemia

Corynebacterium diphtheriae Diphtheria

Yersinia enterocolitica Pharyngitis, enterocolitis

Yersinia pestis Plague

Mycoplasma pneumoniae Bronchitis, pneumonia Chlamydophila pneumoniae Bronchitis, pneumonia Chlamydophila psittaci Psittacosis

Question 119

Infectious exacerbation: bronchiectasis grows Pseudomonas: Rx

Answer 119

Switch from levofloxacin to ciprofloxacin

Question 120

A 23-year-old man presents with near-syncope; longstanding Crohn disease moderately controlled. About 2 months ago, he started infliximab. The therapy initially worked well, but 10 days ago his watery diarrhea and low-grade fevers returned. He underwent outpatient colonoscopy yesterday and “has been light-headed.”

Moved to New Jersey from Ohio about 4 years ago. Current medications are sulfasalazine, prednisone, infliximab, and loperamide.

• tachycardic with dry oral mucosa. Lung sounds are diminished at both bases. Painful erythema over the left wrist and forearm. Scattered verrucous plaques with central ulceration on trunk and back. His axillary and inguinal lymph nodes are enlarged.

TST 3 months ago was negative. Induced sputum examination performed 1 week ago was negative for acid-fast bacillus. Yesterday’s colonoscopy describes “several colonic ulcers with heaped-up edges and necrotic centers concerning for uncontrolled Crohn disease.”

White blood cell count = 10,900/µL (reference range, 4500-10,000/µL)
Hemoglobin = 10.6 g/dL (reference range, 13.8-17.2 g/dL)
Platelet count = 130 × 103/µL (reference range, 150-450 × 103/µL)
Creatinine = 1.2 mg/dL (reference range, 0.7-1.3 mg/dL)
Aspartate aminotransferase = 473 U/L (reference range, 20-48 U/L)
Alanine aminotransferase = 307 U/L (reference range, 10-40 U/L)
Chest x-ray shows bilateral hilar lymphadenopathy. Peripheral blood smear is reported as showing “atypical leukocyte morphology”

Answer 120

Histoplasma capsulatum is a dimorphic fungus endemic in the Ohio River Valley and the mid-Atlantic.

Exposure to contaminated soil. Risk activities include cave exploring, cleaning chicken coops, and disturbing soil below bird-roosting sites.

Disseminated histoplasmosis causes multiorgan illness that mimics autoimmune disease or malignancy. Most patients experience fevers and malaise. Seventy to ninety percent of patients have diarrhea, colonic inflammation, or gastrointestinal hemorrhage.

Skin lesions range from papules to plaques and have a distinct tendency to localize to the face, upper chest, and arms.

Other potential signs include pulmonary infiltrates, oral mucosal ulcerations, hepatitis, and lymphadenopathy.

Peripheral blood smear or biopsy of involved tissues often shows Histoplasma-laden phagocytes.

Question 121

Antigenic characteristics determined by surface-spike glycoproteins:

Answer 121

hemagglutinin activity (HA) or neuraminidase activity (NA)

Question 122

_ attaches to erythrocytes and initiates infection; _ cleaves _ , allowing viral release from infected cells

Answer 122

Hemagglutinin

Neuraminidase

Question 123

Seasonal influenza outbreaks typically in epidemic pattern, peaking at _ to _weeks after introduction and completed after _ to _ weeks in any given community

Answer 123

2, 3

5,6

Question 124

Influenza RIDT sensitivity, specificity

Answer 124

1. Sensitivities: 50-70%
2. Specificities: 90-95%

Question 125

Influenza symptoms

Answer 125

abrupt onset:

1. fever,
2. rigors,
3. malaise,
4. headache,
5. myalgia
6. arthralgia

Question 126

Clinical presentation in an individual during community outbreak is _ % specific for influenza based on abrupt onset of cough and fever in an adult

Answer 126

70

Question 127

Influenza: complications other than pneumonia

Answer 127

1. rhabdomyolysis
2. myocarditis,
3. Guillain-Barré syndrome

Question 128

Difference between drift and shift

Answer 128

Antigen-change Immunogenicity-change Drift Minor Minor Shift Major Major

Question 129

Influenza: lab dx methods

Answer 129

1. rapid antigen test (70% specific), 15 minutes
2. PCR (90–100% specific) 20 minutes
3. Immunofluorescence, Direct (DFA) or Indirect (IFA) Florescent Antibody Staining: 1-4 hours
4. Culture (90–100% specific ), days

Question 130

Influenza: major complication

Answer 130

Pneumonia

Question 131

Why are neuramindase inhibitors preferred?

Answer 131

Since 2009 circulating strains have been resistant to amantadines.

Question 132

Influenza: types of pneumonia

Answer 132

1. Viral: from influenza
2. Post-infectious (following recovery) with S. pneumoniae, S. aureus, S. pyogenes, or H. influenzae

Question 133

Itchy, raised patches with scaly borders and clear centers; Dx/Rx

Answer 133

Tinea corporis

Terbinafine

Griesofulvin if severe

Question 134

Joint-Infections

RA+joint effusion+leukocytosis to 35K

Gram stain negative for organisms

Answer 134

Empiric antibiotics

Question 135

Lady Windermere syndrome

Answer 135

Right middle lobe bronchiectasis and Mycobacterium avium complex infection with history of habitual suppression of cough

Question 136

Lemiere syndrome: cause

Answer 136

Fusobacterium necrophorum

Question 137

Lemierre syndrome

Answer 137

Jugular vein suppurative thrombophlebitis

frequently preceded by pharyngitis, usually in association with tonsil or peritonsillar involvement. Other antecedent conditions include primary dental infection or infectious mononucleosis

Question 138

Leprosy: Rx

Answer 138

1. Paucibacillary: Dapsone daily plus rifampin monthly for 6 months
2. Multibacillary: Dapsone daily plus rifampin monthly plus clofazimine for 1 year

Question 139

Less than _% of patients with COPD is caused by non-smoking etiologies (Eg occupational or environmental exposure)

Answer 139

10

Question 140

LGV proctitis L2 serovar: Cause and Rx

Answer 140

Chlamydia trachomatis

Doxy x 3 weeks

Question 141

LTBI: percent who progress to active TB

Answer 141

5%

Question 142

LTBI: Rx

Answer 142

Preferred : INH 9 months; alternative: Rifampin 4 months

Question 143

Why is hemodynamically stable complete heart block due to Lyme treated with ceftriaxone?

Answer 143

The CHB is reversed with antibiotic Rx

Question 144

MDR-TB

Answer 144

Resistance to INH + Rifampin or more drugs

Question 145

MDR-TB: Rx duration

Answer 145

18 to 24 months

Question 146

Meperidine: why not in liver or renal dysfunction?

Answer 146

accumulation of metabolites: CNS toxicity, eg seizure.

Question 147

Middle aged man with mono-like syndrome+ aseptic meningitis: why is this NOT EBV infection?

Answer 147

EBV infection rare in the middle aged, unlikely cause of aseptic meningitis

Question 148

Miliary TB: nature of opacity

Answer 148

faint, reticulonodular infiltrate

• distributed uniformly
• apparent days or weeks after presentation
• nodular interstitial spread without significant alveolar involvement, although it has been demonstrated that, by the time the miliary nodules are large enough to be appreciated on a plain chest radiograph, they typically involve the adjacent alveoli.

Question 149

Moderately severe diabetic foot infection without MRSA risk factors: Rx

Answer 149

Clindamycin + ciprofloxacin

Question 150

Morphine: why avoid in cirrhosis?

Answer 150

markedly decreased clearance, increased bioavailability

• accumulation of morphine metabolites : seizures, encephalopathy, and myoclonus.

Question 151

Most common infection reported in the United States, with more than 1.5 million cases reported in 2015

Answer 151

Chlamydia

Question 152

MRSA bactermia: complicated and uncomplicated, duration

Answer 152

Vancomycin

Uncomplicated: at least 2 weeks

Complicated: 4 to 6 weeks

Question 153

Mycobacteria: clinically important

Answer 153

1. Mycobacterium tuberculosis
2. Mycobacterium leprae
3. Mycobacterium avium complex

Question 154

Non-endoscopic H pylori tests

Answer 154

1. Serologic test
2. Urea breath
3. Fecal antigen test

Question 155

Nearly _% of patients experience an adverse event within 3 weeks of discharge. Of these, _%are considered preventable and _% ameliorable.

Nearly _% of patients suffer an adverse event during hospitalization, of which more than _% are preventable.

Answer 155

Nearly 20% of patients experience an adverse event within 3 weeks of discharge. Of these, 33% are considered preventable and one-third ameliorable.

Nearly 10% of patients suffer an adverse event during hospitalization, of which more than 50% are preventable.

Question 156

Most RCTs for H. pylori eradication in patients with nonulcer dyspepsia have shown _ significant benefit regarding symp- toms; a few have shown a _ benefit, but this can be explained by the _ of _ _.

Answer 156

Most RCTs for H. pylori eradication in patients with nonulcer dyspepsia have shown no significant benefit regarding symp- toms; a few have shown a marginal benefit, but this can be explained by the presence of unrecognized ulceration.

Question 157

NSAID: safe in cirrhosis?

Answer 157

Relatively contraindicated

Risk of HRS, renal injury

Question 158

occur when one fails to know proper rules or when one does not apply the rule he or she knows to be correct.

Answer 158

Rule-based errors

Question 159

Organisms in prostatic abscess

Answer 159

E. coli and Staph aureus

Question 160

Otitis media with effusion: indication for myringotomy

Answer 160

Air travel cannot be avoided; failure of fluid to resorb

Question 161

Patient groups in acute bronchitis

Answer 161

1. Group 1: no risk factors
2. Group 2: + risk factors
3. Group 3: chronic suppurative bronchitis

Question 162

Pediculosis: what kind of organism causes it?

Answer 162

Wingless insects about 1.3 to 2 mm long

1. Pthirus pubis (Crab louse)
2. Pediculus humanus capitis

Both obligate ectoparasites which feed on human blood.

Question 163

Pemphigus: biopsy

Answer 163

autoantibody deposition on DFA

Question 164

Pemphigus: pathogenesis

Answer 164

autoantibodies that compromise keratinocyte adhesion.

Question 165

Penicillin V dose for GAS pharyngitis

Answer 165

1. 250 mg four times daily or 500 mg twice daily orally;
2. long-acting intramuscular PCN given as one dose (1.2 million units benzathine ± procaine PCN G)

Question 166

A 26-year-old man presents to the outpatient clinic with purulent penile discharge. Stain: Gram-negative intracellular diplococci. Recommended treatment does not include

1. Cefixime 400 mg PO and azithromycin 1 g PO once
2. Ceftriaxone 250 mg IM and azithromycin 1 g PO once
3. Azithromycin 2 g PO once
4. Ciprofloxacin 500 mg PO and azithromycin 1 g PO once

Answer 166

Ciprofloxacin is no longer recommended due to levels of resistance greater than 5% in the United States.

Azithromycin dosed at 1 g PO will not treat gonococcal infections effectively as a single agent, but will treat for coinfection with Chlamydia trachomatis.

Question 167

Pertussis should be suspected if cough persists beyond _ weeks;

Answer 167

3

Question 168

Pharyngeal Gonorrhea treated with oral cephalosporin: FollowupTrigger

Answer 168

Test-of-cure 2 to 3 weeks after therapy

Question 169

Pharyngitis: Most common cause is __ in adults, with a much higher incidence of _ in children

Answer 169

Most common cause is viral in adults, with a much higher incidence of GAS in children

Question 170

PID: Organisms

Answer 170

1. N. gonorrhoeae
2. C. trachomatis
3. Anaerobes, gram-negative bacilli, streptococci, and mycoplasmas

Question 171

PID: Rx

Answer 171

1. (Cefotetan or cefoxitin) p+ doxycycline
2. Clindamycin plus gentamicin

Question 172

Pneumococcal vaccine: indications

Answer 172

1. > 65
2. Immunocompromised
3. CSF leak
4. Cochlear implant
5. Nursing home resident of any age.
6. Alcoholism
7. Liver disease
8. DM
9. Chronic heart disease
10. Chronic lung disease
11. Smokers

Question 173

Pneumococcal vaccine: types

Answer 173

PSV13 and PPSV23

Question 174

Pneumonia is _ if vital signs and chest examination are normal

Answer 174

unlikely

Question 175

Healthy patient presents with fever, dyspnea, and a productive cough is given empiric amoxicillin/clavulanic acid for audible pulmonary consolidation. He returns with:

Severe dyspnea

Persistent fever

New diarrhea

Confusion

pO2 < 60 mmHg

Serum Na < 140 mEq/dL

What is the diagnosis?

Answer 175

Legionella community-acquired pneumonia.

Explanation: Unresponsiveness to beta-lactams, confusion, hyponatremia, diarrhea, and pneumonia. In aggregate, these signs and symptoms = Legionella.
Dx: Legionella urinary antigen (diagnoses L. pneumophila type 1 infection = 90% of cases) + Legionella culture of respiratory specimens on buffered charcoal yeast extract agar (for subsequent epidemiologic investigation, if index case).

Rx: Azithromycin or respiratory quinolone (levofloxacin).

Question 176

Leading causes

Answer 176

S. pneumoniae and Legionella pneumophila

Question 177

Dilation of ureters, decreased ureteral peristalsis, and decreased bladder tone in pregnancy increases the risk of:

Answer 177

UTI

Question 178

Primary syphilis: when does chancre appear?

Answer 178

2-3 weeks after innoculation

Question 179

Proctitiis: Workup

Answer 179

1. N. gonorrhoeae and C. trachomatis NAA tests highest sensitivity to detect
2. HSV Culture
3. Syphilis Serology

Question 180

Prophylaxis after sexual assault

Answer 180

ceftriaxone+azithromycin+metronidazole+ Hep B Consider HIV post exposure prophylaxis

Question 181

Prostatitis: Augmenting manouver for diagnosing

Answer 181

“Milking” the prostate by digital examination before voiding may induce pyuria

Question 182

Protozan which causes vaginal discharge

Answer 182

Trichomonas vaginalis

Question 183

Pseudomonas.VAP.Mx

Rx when a sensitive Pseudomonas is found

Answer 183

7 days cefepime

Double cover when suspected; narrow once sensitivities are available

Clin Infect Dis. 2016 Sep 1;63(5):e61-e111. doi: 10.1093/cid/ciw353. Epub 2016 Jul 14.

Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society.

Question 184

A 50-year-old man presents to the hospital with a 2-day history of malaise, subjective fevers, joint pains, and a new purpuric rash over both lower extremities.

2 weeks ago, his primary care physician prescribed hydrochlorothiazide. His temperature is 100.6°F. His lower-extremity examination reveals bilateral edema and a purpuric rash; It is confined to the bilateral lower extremities and does not extend to the feet.

Answer 184

Cutaneous small vessel vasculitis (CSVV) is defined as a single-organ, skin-isolated leukocytoclastic vasculitis (LCV) or angiitis without systemic vasculitis or glomerulonephritis. (See ‘Definitions’ above.)

Question 185

Pyelo: blood culture sensitivity

Answer 185

20%

Question 186

About _% to _% of patients with untreated bacteriuria early in gestation progress to pyelonephritis later in pregnancy. Pyelonephritis has been associated with premature delivery.

Answer 186

20, 40

Question 187

Diagnosis of pyelonephritis is supported by significant bacteriuria or greater than _ CFUs/mm3 and pyuria of more than _ WBCs/mm3

Answer 187

100000

10 WBCs/mm3

Question 188

Rapid strep test: Sensitivity, specificit

Answer 188

Sensitivity: 80%

Specificity: 97%

Question 189

Rare, serious complication of acute prostatitis

Answer 189

Prostatic Abscess

Question 190

Rassmussen error classification

Answer 190

1. Skill-based errors – slips and lapses – when the action made is not what was intended
2. Rule-based mistakes – actions that match intentions but do not achieve their intended outcome due to incorrect application of a rule or inadequacy of the plan.
3. Knowledge-based mistakes – actions which are intended but do not achieve the intended outcome due to knowledge deficits.

Question 191

injury associated with a fall while being cared for in a health care setting.

Answer 191

Reportable

The National Quality Forum, a nonprofit organization known for endorsing quality and safety standards, has endorsed a list of serious reportable events, which were previously known as “never events.” Many states mandate reporting of serious reportable events to their respective departments of health .

Question 192

Reserpine efficacy

Answer 192

• roughly to the same degree as other first-line antihypertensive drugs.

However, we could not make definite conclusions regarding the dose-response pattern because of the small number of included trials. More RCTs are needed to assess the effects of reserpine on blood pressure and to determine the dose-related safety profile before the role of this drug in the treatment of primary hypertension can be established.

Question 193

Respiratory alkalosis and anion-gap metabolic acidosis. Secondary symptoms include tinnitus, gastrointestinal distress, and cardiac arrhythmias.

Answer 193

Aspirin toxicity

Question 194

Rifampin _ cytochrome p450

Answer 194

Rifampin stimulates cytochrome P450

Drug levels reduced:

1. warfarin
2. OCP
3. Methadone
4. Most PIs
5. Most NNRTIs non-nucleoside reverse transcriptase inhibitors

Question 195

Rx for penicillin allergic ABS

Answer 195

Azithromycin, clarithromycin, doxycycline

Question 196

Rx: cough in acute bronchitis

Answer 196

Albuterol inhalation

Exp: may decrease cough; most beneficial if reduced peak airflow

Question 197

Rx: mild pyelonephritis

Answer 197

Oral quinolones for 1 week

TMP-SMX 2 week

Question 198

Rx: penicilling allergy + GABS pharyngitis

Answer 198

Erythromycin 250 mg four times daily or 500 mg twice daily orally for PCN-allergic patients

Question 199

Rx: UTI in a man

Answer 199

For complicated UTI, antibiotic selection is based on culture data and duration of therapy is generally 7 to 14 days depending on chosen antimicrobial agent

Question 200

Second line rx for ABS?

Answer 200

Augmentin, cefuroxime, cefpodoxime

Question 201

Time of appearance

Answer 201

2-8 weeks after chancre

1. 2 to 8 weeks after appearance of chancre
2. flu-like symptoms, generalized lymphadenopathy, and temporary patchy alopecia
3. macular, maculopapular, papular, or pustular and may involve the whole body or palms and soles
4. Condylomata lata appear as raised, painless, gray-white lesions; are highly infectious; and develop in intertriginous areas and on mucous membranes

Question 202

Sensitivity and specificity of clinical presentation 50% to 75% for GABHS.

Answer 202

50 to 75%

Question 203

Sensitivity in primary is _ %; in secondary syphilis is: _%

Answer 203

70, 100

Question 204

Serotonin syndrome vs NMS

Answer 204

NMS: 1 to 2 weeks after starting drug

Serotonin syndrome: much sooner

NMS: high CK, high AST, and low serum iron levels.

Question 205

For instance, potent agents with a relatively short half-life (such as paroxetine) are highly associated with a serotonin withdrawal toxidrome if the medication is abruptly discontinued. In contrast, agents with a longer half-life or active metabolites (such as fluoxetine) may cause a serotonin toxicity toxidrome even after ____ discontinuation.

Answer 205

4 to 5 weeks

Question 206

Serotonin toxicodrome: causes

Answer 206

1. SSRI
2. selective serotonin reuptake inhibitors,
3. serotonin-norepinephrine reuptake inhibitors
4. TCA

Question 207

Serotonin washout period

Answer 207

2 weeks, 4 weeks if fluoxetine

After discontinuing SSRIs: “wash-out” period of at least 2 weeks before use of other serotonergic agents

If fluoxetine is discontinued, this wash-out period: at least 4 weeks

Question 208

Serous otitis media: Rx

Answer 208

Observation

Question 209

Severe candidemia: Rx

Answer 209

Echinocandin

• inhibit synthesis of glucan in the cell wall

Caspofungin, micafungin, and anidulafungin

Question 210

Should sputum cultures be obtained in COPD exacerbations?

Answer 210

Helpful in severe cases

Question 211

Single, painless papule at the site of inoculation
Erodes into clean base and raised, firm borders
Painless rubbery lymphadenopathy

Answer 211

Syphilis

Question 212

SJS/TEN distinction

Answer 212

SJS: < 10% BSA

TEN: > 30% BSA

SJS/TEN “overlap”: 10% to 30%

Question 213

SJS/TEN: causal drugs and temporality

Answer 213

1. allopurinol,
2. sulfonamides
3. anticonvulsants
4. “oxicam” NSAID.

Symptoms begin 4 to 21 days after exposure.

Less frequently:

1. iodinated contrast,
2. herbal medications,
3. Mycoplasma pneumoniae or CMV infection

Question 214

Strep pneumoniae: morphology and syndromes

Answer 214

Gram +ve diplococcus

1. Pneumonia
2. Bacteremia
3. Meningitis

Question 215

Stress ulcer prophylaxis: downsides

Answer 215

1. H2-blockers and PPIs: risk for VAP.
2. RCTs: conflicting results.
3. No guideline currently recommends routine use of stress ulcer prophylaxis for all intubated patients.

Question 216

Suppressive therapy in genital herpes: does it stop shedding?

Answer 216

No

Question 217

Suspected GAS pharyngitis work up

Answer 217

If(clinical\_suspicion\_is\_high): if(rapid\_strep\_positive): treat(); break(); if(throat\_culture\_positive): treat(); break();

Question 218

Syphilis Rx in patient with pen allergy

Answer 218

Treat after desensitization

Question 219

Syphilis testing: screening and confirmatory

Answer 219

Nontreponemal tests: RPR, VDRL

Because of low specificity, must be confirmed by a treponemal test

Treponemal tests:

1. fluorescent treponemal antibody, absorbed (FTA-ABS)
2. T. pallidum particle agglutination tests

Question 220

TB: NAA detailed performance

Answer 220

Sens: 96%, Spec: 95% in Smear +ve

For 1861 (40.1%) of the 4642 patients whose specimens tested positive for AFB on smear, the NAA test had a sensitivity of 96.0%, a specificity of 95.3%, a PPV of 98.0%, and an NPV of 90.9%. For 158 patients whose specimens tested negative for AFB on smear, the NAA test had a sensitivity of 79.3%, a specificity of 80.3%, a PPV of 83.1%, and an NPV of 76.0%, respectively. For the 215 specimens that tested positive for AFB by smear, we found a sensitivity, specificity, PPV, and NPV of 97.5%, 93.6%, 95.1%, and 96.8%, respectively

Question 221

Sensitivity and Specificity of NAAs in TB

Answer 221

1. Highly specific for M. tuberculosis
2. Highly sensitive in AFB smear–positive patients; only 50% sensitive in AFB smear–negative patients
3. If TB is suspected and NAA is negative, TB not excluded

Question 222

Temporal pattern of influenza symptoms

Fever, rigors, and myalgia peak at _ days, after which cough and nasal congestion predominate

Answer 222

3

Question 223

TEN vs Staph scalded skin

Answer 223

Mucosal involvement Epidermal inv TEN ++ upper layer SSS - All layers

SSSS presents with generalized erythema rapidly followed by the development of flaccid blisters and desquamation. The mucous membranes are not involved.

Sloughing of only the upper layers of the epidermis, in contrast with the subepidermal split with full thickness epidermal necrosis observed in SJS/TEN.

Question 224

Gummatous syphilis results in skeletal, mucosal, ocular, and visceral lesions

Time of onset is _ to _ years after infection

Answer 224

4, 12

Question 225

Tests for H. pylori are of which two types?

Answer 225

Endoscopic and non-endoscopic

Question 226

Tetrabenazine

Answer 226

used for hyperkinetic movement disorders such as tardive dystonia and chorea

may worsen parkinsonism because it depletes dopamine.

Question 227

The highest rates of chlamydial infection are among persons between _ and _ years of age

Answer 227

The highest rates of chlamydial infection are among persons between 15 and 24 years of age

Question 228

The most common viral STD in the United States; most infections asymptomatic and self-limited

Answer 228

Condylomata Acuminata or Anogenital Warts

Question 229

Tick-borne illnesses

Answer 229

1. RMSF: Rickettsia rickettsii
2. Ehrliochosis: Ehrlichia chaffeensis
3. Anaplasmosis: Anaplasma phagocytophilum
4. Babesiosis: Babesia microti
5. Lyme: Borrelia burgdorferi

Question 230

Tigecyline and linezolid: why not in MRSA bacteremia?

Answer 230

1. Both bacteriostatic
2. Tigecyline:does not achieve high blood concentrations

Question 231

Toxic shock syndrome: Rx

Answer 231

Vanc + Zosyn + Clinda

Question 232

Treatment difference between scabies and lice

Answer 232

1. Lice: permethrin 1% cream
2. Scabies: permethrin cream 5%

Both: oral ivermectin

Ivermectin and malathion are alternatives for drug resistant lice.

Question 233

TST Induration Considered Positive: Ranges

Answer 233

5, 10, 15 mm

Question 234

10 mm > TST > 5 mm is considered to be positive for:

Answer 234

1. HIV infection
2. Recent contacts of active TB patients
3. Fibrotic changes on chest radiograph
4. Immunosuppression
5. Use of anti–tumor necrosis factor-α drugs

Question 235

TST False positives: Cx

Answer 235

1. NTM infection
2. BCG vaccination

Question 236

Uncomplicated cystitis: organisms

Answer 236

E. coli

Staphylococcus saprophyticus

Question 237

Urine culture: male with UTI, should we get one?

Answer 237

Yes, because this is a complicated UTI by “definition.”

Question 238

Urodynamic testing components

Answer 238

1. cystometry (measuring bladder pressure during filling of the bladder)
2. uroflowmetry (measuring urine flow over time)
3. pressure-flow study (determining whether poor flow is due to obstruction or detrusor weakness)
4. urethral pressure profile or leak point pressure (for diagnosis of intrinsic sphincter deficiency).

Question 239

Urodynamic testing: utility

Answer 239

1. diagnosis of lower urinary tract dysfunction is unclear
2. objective findings do not correlate with symptoms
3. Failure to improve with treatment
4. surgical treatment is planned.

Question 240

In areas where resistance to TMP-SMX is less than _%, this drug can be used twice daily for 3 days. Other agents include quinolone therapy for _ days or nitrofurantoin for _ days

Answer 240

In areas where resistance to TMP-SMX is less than 20%, this drug can be used twice daily for 3 days. Other agents include quinolone therapy for 3 days or nitrofurantoin for 5 days

Question 241

Vaginal discharge: foul smelling, frothy, yellow. Dx and Rx.

Answer 241

Trichomoniasis

PCR

Single dose (2 g) oral metronizadole

Question 242

Vaginal discharge: white, noninflammatory, coating

Answer 242

Bacterial vaginosis

1. Replacement of normal Lactobacillus spp. with anaerobes

Question 243

Vaginal discharge: Clue cells
Vaginal pH >4.5 + whiff test (fishy odor on addition of 10% KOH). Rx?

Answer 243

Twice daily metronidazole (500 mg) x 1 week

Bacterial vaginosis

Question 244

Vaginal discharge: White, “cottage cheese”

Answer 244

Vulvovaginal candidiasis

Candida albicans

OTC: Clotrimazole 2% cream 5 g intravaginally daily for 3 days

Fluconazole 150 mg orally once

external dysuria and vulvar pruritus, pain, swelling, and redness. Vulvar edema, fissures, excoriations, and thick curdy vaginal discharge.

Question 245

VAP prevention

Answer 245

ATS/IDSA and SHEA guidelines: intubated patients be semirecumbent.

SHEA: head of bed at 30 to 45 degrees

as an accepted VAP-decreasing measure.

Question 246

VAP: bugs

Answer 246

1. Aerobic gram-negative bacilli such as Pseudomonas aeruginosa,
2. Klebsiella pneumonia,
3. Acinetobacter species or
4. gram-positive cocci such as Staphylococcus aureus, much of which is methicillin-resistant Staphylococcus aureus.
5. Legionella can be considered in the appropriate clinical scenario, but it is not common.
6. Anaerobes and fungi are uncommon causes of VAP.

Question 247

VAP: Rx

Answer 247

1. Gram-negative bacilli: antipseudomonal cephalosporin (ie, ceftazidime) OR antipseudomonal carbapenem (ie, imipenem) OR b-lactam/b-lactamase inhibitor (ie, piperacillin/tazobactam)
2. PLUS antipseudomonal fluoroquinolone (ie, levofloxacin) OR aminoglycoside (ie, tobramycin).
3. Vancomycin or linezolid should also be included to cover methicillin-resistant Staphylococcus aureus.

Question 248

VAP: why is vancomycin + Zosyn inadequate?

Answer 248

Also needed: antipseudomonal fluoroquinolone OR aminoglycoside

Question 249

Vestibular neuronitis: Rx

Answer 249

Meclizine

Question 250

Viral-Hepatitis.Hepatitis-B.Mx

Chronic inactive Hep B

Answer 250

ALT Q6Month, Hep B DNA Q6-12Month

Question 251

1. occurs in about one-third of secondary syphilis patients
2. painless, mucosal, and warty erosions
3. flat, velvety, moist and broad base . They tend to develop in warm, moist sites of the genitals and perineum.
4. highly infectious.
5. Complete resolution is spontaneous and occurs after a few days to many weeks, where it is either resolved completely or enters the tertiary phase, defined by a latent state.[2]

Answer 251

Condylomata lata

Question 252

Weber test

Answer 252

Laterazlizes to the side with conductive loss or opposite to the side with sensorineural loss.

Tuning for test

Heard equally in both sides: Normal

Lateralizes to good ear: Sensorineural loss in other ear

Lateralizes to bad ear: Conduction loss in bad ear

In an affected patient, if the defective ear hears the Weber tuning fork louder, the finding indicates a conductive hearing loss in the defective ear. In an affected patient, if the normal ear hears the tuning fork sound better, there is sensorineural hearing loss on the other (defective) ear.

However, the aforegoing presumes one knows in advance which ear is defective and which is normal (such as the patient telling the clinician that they cannot hear as well in one ear versus the other) and the testing is being done to characterize the type, conductive or sensorineural, of hearing loss that is occurring. In the case where the patient is unaware or has acclimated to their hearing loss, the clinician has to use the Rinne test in conjunction with the Weber to characterize and localize any deficits. That is, an abnormal Weber test is only able to tell the clinician that there is a conductive loss in the ear which hears better or that there is a sensorineural loss in the ear which does not hear as well.

For the Rinne test, a vibrating tuning fork (typically 512 Hz) is placed initially on the mastoid process behind each ear until sound is no longer heard. The fork is then immediately placed just outside the ear with the patient asked to report when the sound caused by the vibration is no longer heard. A normal or positive Rinne test is when the sound heard outside the ear (air conduction or AC) is louder than the initial sound heard when the tuning fork end is placed against the skin on top of the mastoid process behind the ear (bone conduction or BC). Therefore, AC > BC; which is how it is reported clinically for a normal or positive Rinne result. In conductive hearing loss, bone conduction is better than air or BC > AC, a negative Rinne.

Question 253

Weeping patches which develop honey colored crusts

Answer 253

Impetigo

Staph. aureus

Question 254

Which disease: egg deposition in the intestines, liver and GU tract?

Answer 254

Schistosomiasis

Question 255

Which is worse: SJS or TEN?

Answer 255

TEN (more extensive)

Question 256

Which organism can be treated with single dose metronidazole?

1. Bacterial vaginosis
2. Trichomoniasis

Answer 256

Trichomoniasis

Bacterial vaginosis: 1 week twice daily metronidazole (500 mg). Single dose (2 g) oral metronizadole is only recommended for the treatment of trichomoniasis and should not be used to treat bacterial vaginosis.

Question 257

Which patients with acute bacterial sinusitis should be treated?

Answer 257

Moderate, Severe symptoms

Question 258

White discoloration, crumbly debris from beneath the nail, and thickening of the nail: Dx/Rx

Answer 258

Tinea unguium (onychomycosis)

1. Oral terbinafine or itraconazole for 6–12 wk
2. Ciclopirox nail lacquer is effective in <10% of patients

Question 259

Why do we treat pertussis?

Answer 259

For public health reasons

Azithromycin or tetracycline

Question 260

Why is cefazolin not a good agent for MRSA?

Answer 260

No activity against MRSA

Question 261

Why screen for chlamydia?

Answer 261

reduced incidence of PID (RCT data)

Question 262

Winnipeg Criteria: basis

for Stratifying Severity of Acute Exacerbation of Chronic Bronchitis

(this is a bizarre system)

Answer 262

Symptoms

1. Increasing dyspnea
2. Increasing purulence of sputum
3. Increasing volume of sputum

Classification

1. Type 1: Severe, all three symptoms
2. Type 2: Moderate, two or three symptoms
3. Type 3: Mild, at least one symptom along with
   
   1. URTI within last 5 days
   2. Fever without other apparent cause
   3. Increased wheezing
   4. Increased nonproductive cough
   5. Increased respirations or pulse >20% over baseline

Question 263

An 18-year-old woman presents with right knee pain that began 4 days ago. Her right ankle had hurt previously and she thinks she hurt the knee by favoring the ankle. She also notes some soreness in her left wrist when she lifts her infant. She does not use injection drugs.

Two bug bites on her palms. Pain over the radial aspect of the left wrist along the tendon sheath and has two small erythematous pustules on left palm.

Rright knee is painful on range of motion, but has no erythema, warmth, or tenderness.

Arthrocentesis reveals a white blood cell (WBC) count of 1000/mm3. No organisms are identified on Gram stain. Which of the following is appropriate?

Answer 263

DGI: tenosynovitis, dermatitis, and migratory polyarthralgia, or as a monoarticular septic arthritis.

Presentation here: left-wrist synovitis, acral lesions consistent with the pustular or vesicular lesions seen in DGI, and polyarthralgia.

Urogenital symptoms sensitivity for DGI: 25% in DGI.

Sensitivity of joint fluid culture: 50%

Rx: ceftriaxone and doxycycline for concomitant chlamydia.

Question 264

Gram negative helical rod

Answer 264

H. pylori

Question 265

Pneumonia.Causes

Most likely cause of a chronic pneumonia in a patient without TB exposure

Answer 265

Fungal

Blasto, Histo, coccidio

Question 267

Cystic-fibrosis

Acute Pseudomonas infection in CF

Answer 267

IV ceftazidime + IV tobramycin

Question 268

Hepatitis C: which malignancy is it associated with?

Answer 268

B-cell non-Hodgkin lymphoma

Limited data also suggest the possibility of beneficial effects on the natural history of lymphoma with antiviral treatment. In one case report, remission of follicular lymphoma occurred following successful direct-acting-antiviral treatment for underlying HCV infectio

Question 269

Nocardiosis: most common extra-pulmonary dissemination site

Answer 269

CNS

Question 270

Fluffy white necrotizing retinitis + chorioretinal scarring

Answer 270

Toxoplasma gondii

Meta: never seen a case

CMV does not cause vitreal inflammation

Question 271

Serotonin syndrome: which antibiotic?

Answer 271

Linezolid

Question 272

MRSA bacteremia: Rx

Answer 272

IV vancomycin for 6 weeks

Question 273

Polymicrobial Gram negative infection + immunosuppresion: which intestinal parasite?

Answer 273

Strongyloides

Question 274

Malaria prophylaxis: how long to continue after returning?

Answer 274

Doxy: 4 more weeks

Proguanil: 1 more week

Contrary to a common perception, antimalar ial agents such as chloroquine, mefloquine, and doxycycline do not prevent initial malaria infec- tion in humans; rather, they act later on parasites that infect erythrocytes once they have been re- leased from the initial maturation phase in the liver (Fig. 2). Therefore, these drugs must be con- tinued for 4 weeks after the last exposure to in- fective mosquitoes in order to eradicate any para- sites that may still be released from the liver in the next month. However, atovaquone–proguanil not only acts on these blood-stage parasites but also interferes with the development of actively replicating parasites in the liver (Fig. 2); there- fore, it can be discontinued 1 week after expo- sure ends.

Question 275

lupus patient with h/o chronic prednisone use presents with weeks of:

Intermittent fevers

Headaches

Confusion

CSF: Opening pressure > 200 mm H20, 20–200 leukocytes/hpf (↑ monocytes), ↑ protein, ↓ glucose; Gram stain: No organisms

Answer 275

cryptococcal meningitis.

Explanation

The big clues are the history of chronic steroid use and the very high opening pressure in the CSF. Crypto is notorious for increasing CSF pressure in this manner.
Dx: Serum crypto antigen + CSF opening pressure, crypto antigen, cell count, protein, glucose, and fungal culture.
Tx: Amphotericin B + flucytosine as induction, and then switch to fluconazole + keep ICP < 20 cm with repeated lumbar taps or insertion of ventriculoperitoneal shunt.

Question 276

exually active patient presents with:

Fever

Headache

Myalgias

Scattered lymphadenopathy

Disseminated maculopapular rash, including the palms and soles ± wet-appearing, whitish plaques on the mouth and/or genital mucosa

Answer 276

secondary syphilis.

Explanation

If the script had not used the words “palms and soles,” you might have guessed a variety of answers, including influenza, mono, RMSF, meningococcemia, and primary HIV infection, etc. Questions about syphilis might describe the rash on the palms and soles as “nickel-and-dime lesions.” The whitish plaques are condyloma lata lesions that are manifestations of secondary syphilis.

Dx: Clinical + RPR or VDRL for screening + MHA-TP or FTA-ABS for confirmation of positive screening test

Question 277

oung adult who did not receive childhood vaccines returns from a vacation to South America with:

Low-grade fever

Pharyngeal pain

Gray pharyngeal exudate

What is the diagnosis?

Answer 277

diphtheria.

Explanation

This diagnosis is pretty easy to remember, but the major cause of mortality from diphtheria (toxin-induced myocarditis) is not. Stridor and respiratory compromise also can occur if the membrane enlarges. The systemic toxicity is proportional to the size of the pharyngeal membrane.
Dx: Toxin assay + culture of organism from respiratory specimens.
Tx: Either erythromycin or penicillin G + antitoxin. Treat all cases.

Question 278

Elderly, hospitalized, diabetic patient with h/o heart failure presents with:

Fever

Cough

Confusion

Hypoxemia

CXR: Lobar consolidation

Blood cultures: Gram-positive cocci in chains

Sputum Gram stain and culture: Gram-positive cocci in long chains

What is the etiology of the pneumonia?

Answer 278

roup B streptococci (S. agalactiae).

Explanation

GBS is now recognized as a bona fide etiology of severe pneumonia in the elderly. You should know its unique features: high rate of coexisting bacteremia, often causes confusion, and predilection for hospitalized patients with history of HF and/or diabetes. You might have guessed pneumococcus as the cause, but they are lancet-shaped diplococci and do not appear in long chains.

Dx: Cultures of respiratory samples or blood.

Tx: Intravenous PCN G or ampicillin.

Question 279

24–48 hours after visiting Peru and eating raw oysters, patient presents with:

Profuse, watery diarrhea with flecks of mucus

± Watery vomiting

↓ BP

No fever

What is the diagnosis?

Answer 279

cholera.

Explanation

Watery diarrhea with flecks of mucus is often described as “rice water diarrhea” because of the appearance. The diarrhea from cholera is so profuse, it quickly distinguishes itself from other forms of self-limited gastroenteritis. Patients have so many watery stools that they can dehydrate within hours. Abdominal pain and fever are absent.
Dx: Stool for Gram stain and culture (“sheets of curved gram-negative rods”).
Tx: Aggressive volume resuscitation and replacement; patients can die within hours, so replacement should begin quickly, followed by antibiotics (doxycycline or quinolones).

Question 280

Sexually active female at the end of her menstrual cycle presents with:

Diffuse arthralgias

Fever

Tenosynovitis of multiple fingers

A half-dozen pustular nodular skin lesions

What is the diagnosis?

Answer 280

disseminated gonorrhea.

Question 281

Sexually active female presents with:

Thin, yellowish, vaginal discharge

Dysuria

Dyspareunia

Cervix: Punctate hemorrhages

Vaginal pH > 4.5

Wet mount: motile organisms

Answer 281

Trichomonas

Metronidazole

Question 282

10 days after returning from a vacation to Austin, Texas, to watch the bats emerge from under the bridges, patient develops:

Fever and chills

Headache

Cough

Pulmonary rales

CXR: Hilar adenopathy and patchy interstitial infiltrates

What is the diagnosis?

Answer 282

pulmonary histoplasmosis.

Explanation

The exposure history is the key here. Think about histo with any of the following exposures: farm buildings, caves, bird-roosting locations, bat guano, and “spelunking” (cave exploration) with exposure to the Southeast and South Central U.S.
Dx: The sensitivity of the different tests for histo vary depending on the presentation of disease. The antigen tests are useful in patients with very severe disease. Diagnose pulmonary histo with fungal stains and cultures of sputum ± histo antigen on urine, blood, or bronchoalveolar lavage specimens in sick individuals + serum complement fixation antibody test.
Tx: Lipid amphotericin B preparations for very severe disease; itraconazole for less severe disease.

Question 283

4 days after killing and skinning a rabbit, patient presents with:

Fever

Chills

Headaches

Erythematous papule on the hand

Axillary lymphadenopathy

Answer 283

tularemia.

Explanation

Tularemia is caused by Francisella tularensis, a small, gram-negative pleomorphic bacillus found in many animals, specifically rabbits.
Dx: 4-fold rise in acute and convalescent IgG and IgM serum titers + Gram stain and culture of clinical specimens (usually difficult to demonstrate the organism) ± PCR in research setting.
Tx: Treat with streptomycin or gentamicin. Tetracycline can be used if the patient is not severel

Question 284

SLE on chronic prednisone presents with prolonged:

Fevers

Dyspnea

Productive cough

Night sweats and weight loss

CXR: Multiple nodules and interstitial infiltrates

TB skin test: No induration

Sputum Gram stain: Filamentous, branching, gram-positive rods that are partially acid-fast

Head CT with contrast: Singular mass lesion

What is the diagnosis?

Answer 284

Nocardiosis

Question 285

Patient with known hemochromatosis on chelation therapy ingested raw oysters from the Chesapeake Bay, then presented with:

Fever

↓ BP

Multiple hemorrhagic bullae

↓ Plt

↑ PT, PTT, fibrin degradation products, and ↓ fibrinogen

What is the diagnosis?

Answer 285

ibrio vulnificus septicemia.

Explanation

The association of iron overload, raw oysters, bullous skin lesions, and a sepsis syndrome is the key to recognizing V. vulnificus. Most cases are acquired in the Chesapeake Bay or on the U.S. Gulf Coast.
Dx: Bacterial cultures of clinical specimens (blood, wounds).
Tx: Supportive + doxy + either cefotaxime or ceftriaxone + surgical debridement.

Question 286

weeks after returning from a missionary trip to Cameroon, Africa, patient presents with:

Fevers and chills

Malaise

Headaches

Nonspecific abdominal pain

Vomiting

Splenomegaly

↓ Hgb, Hct, and Plt

↑ Serum AST, ALT, and T. bili

± ↑ BUN and creatinine

Thin smears: Banana gametocytes

What is the diagnosis?

Answer 286

Plasmodium falciparum malaria.

Explanation

Any patient who returns from a malaria-endemic area with fevers and splenomegaly should be considered to have malaria until proven otherwise. This case also includes the buzz phrase “banana gametocyte.” When you see that, the diagnosis is P. falciparum malaria. Remember, malaria does not characteristically have a rash!
Dx: Thick and thin blood smears stained with Giemsa for identification of parasites (banana gametocytes and ring forms in P. falciparum) ± various rapid diagnostic test.
Tx depends on severity of disease and area of travel: Chloroquine-sensitive mild disease = chloroquine; chloroquine-resistant or unknown = artemisinin combination (artesunate or artemether + amodiaquine, atovaquone-proguanil, lumefantrine, clinda, doxy, and others), atovaquone-proguanil, quinine + pyrimethamine-sulfadoxine, doxy, or clinda, or mefloquine and d

Question 287

Sexually active female presents with:

Thin vaginal discharge with a “fishy” odor

Vaginal pH > 4.5

+Whiff test

Wet mount: clue cells

Answer 287

bacterial vaginosis.

Explanation

“Clue cells” is your clue to this script, in addition to the high pH, fishy odor, and +whiff test. Trichomonas is the other organism that can cause a thin vaginal discharge, but it is visible on wet prep.
Dx: Vaginal pH > 4.5 + whiff test + wet mount (clue cells).
Tx: Oral or intravaginal metronidazole or clindamycin.

Question 288

Bacterial vaginosis vs Trichomonas

Answer 288

Bacterial vaginosis: clue cells

Trichomonas: visible

The diagnosis of Trichomonas vaginalis is based on laboratory testing (motile trichomonads on wet mount, positive culture, positive nucleic acid amplification test, or positive rapid antigen or nucleic acid probe test). Because microscopy is a key step in the evaluation of vaginal discharge, it is often the first step in the diagnostic evaluation for trichomoniasis. Microscopy is convenient and low cost. Nucleic acid amplification tests (NAAT) can then be done for women with non-diagnostic (or negative) wet mounts. If NAAT is not available, rapid diagnostic kits or culture are then performed. The choice of test is based on availability.

As with other types of vaginitis, none of the clinical features of trichomoniasis is sufficiently sensitive or specific to allow a diagnosis based upon signs and symptoms alone (table 1) [38-40]. In one study, if the classic clinical features of trichomoniasis in women were used alone for diagnosis, 88 percent of infected women would not be diagnosed and 29 percent of uninfected women would be falsely diagnosed as infected [41].

Women undergoing testing for trichomoniasis are generally tested for chlamydia and gonorrhea infections as well. The diagnostic approach to women with vaginal discharge is reviewed separately. (See “Approach to women with symptoms of vaginitis” and “Screening for sexually transmitted infections”, section on ‘Screening recommendations’.)

Microscopy and pH — The presence of motile trichomonads on wet mount is diagnostic of infection, but they are identified in only 60 to 70 percent of culture-confirmed cases (picture 2) [40]. The motion is jerky and spinning (movie 1 and movie 2); organisms remain motile for 10 to 20 minutes after collection of the sample. Other findings that are almost invariably present with T. vaginalis infection, but nondiagnostic, include an elevated vaginal pH (>4.5) and an increase in polymorpho

Question 289

lderly patient presents with acute onset:

Confusion and fever

↑ WBC

Differential: ↑ Neutrophils

CSF: ↑ Leukocytes > 100/hpf (polys, lymphs, and monos), ↑ protein, ↓ glucose, Gram stain: No organisms

Blood cultures: + Gram-positive diplococci

What is the diagnosis?

Answer 289

pneumococcal meningitis.

Explanation

Bacterial morphology always helps you make the diagnosis. Pneumococci are “lancet-shaped gram-positive diplococci.” The organisms are usually present on CSF Gram stain; however, a lack of organisms on Gram stain does not exclude bacteria as the cause.
Dx: CSF analysis for cell count, glucose, protein, Gram stain and bacterial culture + blood cultures ± urinary pneumococcal antigen.
Tx: Vancomycin + ceftriaxone, then narrow coverage based on susceptibility results.

Question 290

Hunter from the Midwest presents with:

Fever

Headaches

Myalgias

Splenomegaly

Mild jaundice

↓ Hgb, Hct, and Plt

↑ Indirect bili, reticulocyte count, and ↓ haptoglobin

↑ Serum AST, ALT, alkaline phosphatase, and LDH

Thin smears: Maltese cross merozoites

Answer 290

babesiosis.

Explanation

Dx: Thin blood smears stained with Giemsa to visualize parasites or PCR testing on peripheral blood in patients with negative thin smears ± IgG and IgM serum titer ≥ 1:64.
Tx:

For patients with mild B. microti infection, we recommend treatment with atovaquone-azithromycin (Grade 1B). For asymptomatic patients with babesiosis, we recommend not administering antibiotic therapy (Grade 1C). Treatment should be considered if parasites persist for ≥3 months. (See ‘Mild illness’ above.)

●For patients with severe B. microti infection, we suggest initial antimicrobial therapy with clindamycin plus quinine (Grade 2C). If quinine toxicity occurs, we suggest

Question 291

Hiker from Arkansas presents with:

Fever

Headache

Myalgias

Maculopapular rash that becomes petechial on the wrists and ankles

↓ WBC, Hgb, Hct, and Plt

↓ Serum Na

↑ Serum AST and ALT

↑ PT and PTT

Answer 291

Rocky Mountain spotted fever (RMSF).

Explanation

Look out for the history of exposure to ticks in endemic areas (especially Southeast and South Central U.S.) and the features of pancytopenia, hyponatremia, characteristic rash, and increased transaminases. Not all patients have all of the findings, but this is the classic script. Do not confuse this petechial rash (which is characteristically on the wrists and ankles) with petechiae/purpura due to DIC in patients with meningococcal sepsis (called “purpura fulminans”). Those patients have classic findings of DIC with increased D-dimer and PT and PTT. Ehrlichiosis appears very similar to RMSF, except usually without a rash. The other lab findings are nearly identical.
Dx: Clinical. Skin biopsy for immunofluorescence. 4-fold rise in acute and convalescent IgG and IgM serum titers occurs, but treatment needs to be immediate.
Tx: Empiric oral or parenteral doxycycline in suspected cases; recognize that no diagnostic tests give immediate answers, so do not withhold antibiotics awaiting serology or biopsy findings.

Question 292

Adolescent patient presents with fever, malaise, sore throat, and disseminated pruritic, vesicular rash that progresses to:

Cough and dyspnea

↓ BP

Hypoxemia

CXR: Diffuse bilateral infiltrates

Answer 292

varicella pneumonia.

Explanation

The clue is the development of pneumonia in the setting of an itchy vesicular rash.
Dx: PCR on clinical specimens (skin lesions) + viral culture on clinical specimens (skin lesions, bronchoalveolar lavage fluid) + serum varicella-zoster virus antibodies.
Tx: Oral acyclovir can be used in adults with mild disease; severe disease should be treated with high-dose intravenous acyclovir (10 mg/kg q 8 hours) + supportive care.

Question 293

HIV/AIDS and CD4 count < 50/µL is hospitalized for:

Confusion

Fevers

Multiple erythematous skin papules that develop painless central ulcerations and necrosis

Blood cultures: Gram-negative rods

What is the diagnosis?

Answer 293

ecthyma gangrenosum and Pseudomonas bacteremia.

Explanation

Any time you see disseminated skin lesions with central necrosis in an immunosuppressed person, think about Pseudomonas bacteremia, especially if the patient has an indwelling central catheter. You could have considered disseminated fungal infections, such as Candida, but those lesions generally do not develop central necrosis. You also might have thought of cutaneous anthrax, but those patients usually do not have multiple lesions and initially are not septic. The Gram stain of the blood definitively tells you what is going on with this script. Patients with HIV/AIDS and severe immunosuppression are at risk for spontaneous Pseudomonas bacteremia and pneumonia.
Dx: Culture.
Tx: 2 antipseudomonal drugs are combined with 1 from each of following categories: antipseudomonal beta-lactams (pip/tazo, ticarcillin/clav, cefepime, ceftazidime) + either aminoglycoside (gent or tobra) or quinolone (ciprofloxacin).

Question 294

Nonvaccinated adolescent presents with:

Fevers

Cough

Coryza

Conjunctivitis

Bluish-white spots on the buccal mucosa

Diffuse, maculopapular rash, beginning on the face and moving downward

Answer 294

measles.

Explanation

Coryza is another term for a congested and runny nose. The bluish-white spots are “Koplik spots,” but you should definitely know what these are by description and not in name only. Cough, coryza, conjunctivitis, Koplik spots = measles.
Dx: 4-fold rise in acute and convalescent IgG and IgM serum titers + viral culture of clinical specimens.
Tx: Supportive + measles vaccination (should have ≥ 2 doses).

Question 295

1 week after eating meat from a local bear hunter, several patients develop abdominal pain and diarrhea that eventually progress to:

Myalgias, ocular pain, and muscle swelling

Lower extremity edema

Conjunctival and subungual hemorrhages

Periorbital edema

↑ WBC with differential: ↑ Eosinophilia

↑ Serum CPK

Answer 295

trichinellosis.

Explanation

You probably associate Trichinella spiralis more with undercooked pork, which is also true. The eosinophilia gives this diagnosis away and helps you exclude simple myositis as the cause.
Dx: T. spiralis antibody test ~ 3 weeks after infection + muscle biopsy (shows larvae).
Tx: Treat only symptomatic patients with albendazole.

Question 296

Healthy, sexually active female presents with a recent onset:

Dysuria, urgency, and frequency

U/A: > 10 leukocytes/hpf, no casts; +leukocyte esterase and bacteria

Urine culture: gram-positive cocci in clusters that lab tells you are not S. aureus or S. epidermidis.

What is the diagnosis?

Answer 296

cystitis.

Explanation

Remember that Staphylococcus saprophyticus is a urinary pathogen in females, so do not automatically assume that a urine Gram stain with gram-positive cocci is contaminated.
Dx: Urinalysis ± urine culture or Gram stain of unspun urine.
Tx: Oral cephalosporin or amoxicillin-clavulanic acid

Question 297

Diabetic with history of frequent episodes of ketoacidosis presents with:

Fever

Confusion

High anion gap metabolic acidosis

↑ Blood glucoses

Recent history of chronic, purulent, nasal discharge

A painless black lesion in the anterior nares

What is the diagnosis?

Answer 297

mucormycosis.

Explanation

Mucormycosis (a.k.a. zygomycosis) is caused by fungi in the order Mucorales. The fungi thrive in high glucose,high acid environments e.g. diabetic ketoacidosis. Disease can present as invasive rhinocerebral or invasive pulmonary infection. The black necrotitic lesion represents rhinocerebral involvement and can extend intracranially. The most common presentation is sinusitis in an uncontrolled diabetic.
Dx: Fungal stains and cultures of clinical specimens (tissue biopsies, bronchoalveolar lavage fluid, sinus specimens).
Tx: Aggressive supportive care + surgical debridement + lipid amphotericin B.

Question 298

Sexually active patient presents with:

Painless, small, firm, genital ulceration that remains present for 2–3 weeks

What is the diagnosis?

Answer 298

primary syphilis.

Explanation

You absolutely must know all about genital ulcerations for any comprehensive exam. It is safe to associate any painless genital ulcer with primary syphilis. Painful ulcers are usually herpes or chancroid; the former occurs after clustered vesicles rupture, and the latter is typically large and single. Painless genital ulcer in the U.S. = syphilis.
Dx: + RPR or VDRL for screening + MHA-TP or FTA-ABS for confirmation of positive screening test.
Tx: Single IM injection of PCN G; doxycycline is an alternative for penicillin-allergic patients with the exception of neurosyphilis and pregnant women.

Question 299

2 weeks after cleaning a warehouse in New Mexico that contained rodent droppings, previously healthy patient presents with fever, malaise, myalgias, headaches, and decreased platelets, and rapidly develops:

Progressive bilateral pulmonary interstitial edema, leading to hypoxic respiratory failure

↑ Serum AST, ALT, LDH, and lactate

Prolonged PT and PTT with ↑ D-dimer, fibrin degradation products, and ↓ fibrinogen

What is the diagnosis?

Answer 299

hantavirus pulmonary syndrome.

Explanation

Always think about hantavirus when you see rodents in a clinical history. This is a very rapidly progressive syndrome, so patients with rodent exposure who develop cough should be taken very seriously. Sometimes the rodent history is hard to get (or is left out of an exam question), so think about hantavirus in a patient with a severe pneumonia and exposure to the Desert Southwest.
Dx: 4-fold rise in acute and convalescent IgG and IgM serum titers (usually antibodies are present when patient is symptomatic) + PCR on clinical specimens (peripheral blood, serum).
Tx: Supportive.

Question 300

6 hours after eating mashed potatoes with brown gravy at an office party, several workers develop:

Profuse watery diarrhea x hours

Crampy abdominal pain

No vomiting

What is the diagnosis?

Answer 300

lostridium perfringens food poisoning.

Explanation

Remember the key associations for C. perfringens food poisoning: watery diarrhea and crampy abdominal pain; brown gravy and meats; ingestion of large amounts of bacteria, which then form toxins in the intestine (symptoms occur later, after ingestion). You might have guessed Yersinia enterocolitica. The Yersinia association is with ingestion of chitterlings (pronounced “chitlins”). Yersinia diarrhea usually lasts much longer, however, and can be associated with significant morbidity including mesenteric adenitis.
Dx: Toxin assay of stool. Staphylococcal food poisoning has nausea.
Tx: Supportive ± antidiarrheal agent if the patient has no fever and nonbloody stools.

Question 301

ay male presents with:

Chronic, “smelly” stools that float

Flatulence

“Sulfuric belching”

Weight loss

Negative stool O&P evaluation

What is the diagnosis?

Answer 301

giardiasis.

Explanation

The clinical scenario could include a hiker who drinks mountain water. Don’t let a negative O&P evaluation dissuade you from the diagnosis of Giardia because only ~ 50% of specimens are positive. Sulfuric belching is always a dead giveaway for Giardia—not much else does that. Remember the groups that are at increased risk: men who have sex with men, the immunosuppressed, and those who drink mountain water.
Dx: Stool ova and parasite evaluation + stool Giardia antigen ± duodenal biopsy.
Tx: Treat only symptomatic patients. Choices include metronidazole, tinidazole, or nitazoxanide.

Question 302

Adolescent patient with no respiratory symptoms develops acute onset:

Pharyngeal pain with tonsillar swellings and exudate

Fever

Anterior cervical adenopathy

Heterophile antibody: Negative

What is the diagnosis?

Answer 302

group A streptococcal (S. pyogenes) pharyngitis.

Explanation

Viral pharyngitis is more often associated with respiratory symptoms of coryza and cough, where S. pyogenes pharyngitis rarely is. The 3 findings listed in this script (adenopathy, fever, exudative pharyngitis) are the most specific collection of findings for S. pyogenes. You might have guessed Arcanobacterium as a cause (and that would be reasonable), but
1 clue to this organism is an erythematous rash, which is not present in this patient. The heterophile antibody is the “monospot” test, which is (+) in 60–80% of EBV patients and makes the diagnosis of EBV less likely.
Dx: Rapid strep test; throat cultures are no longer recommended in adults, even when the rapid test is negative.
Tx: Oral penicillin V; amoxicillin, 1st generation cephalosporins, and IM PCN G are alterna

Question 303

Nursing home patient develops:

Perpetual scratching buttocks

Multiple perianal excoriations

Bean-shaped eggs: “Scotch tape test”

What is the diagnosis?

Answer 303

pinworms (Enterobius vermicularis).

Explanation

The scotch tape test is only used to diagnose pinworms; you can safely make that association. Remember that pinworms are not diagnosed on O&P exams of the stool because eggs are not shed in the stool.
Dx: Scotch tape test (scotch tape pressed against perianal skin, then tape pressed onto slide and viewed under the microscope).
Tx: Albendazole.

Question 304

Sexually active female presents with:

A mucopurulent vaginal discharge

A friable cervix with mucopurulent discharge at the cervical os

Wet prep: No organisms

What is the diagnosis?

Answer 304

gonorrhea cervicitis.

Question 305

Previously healthy patient returns from Hawaii after participating in freshwater kayaking and swimming in local waterfalls. 1 week later, he develops:

Fever and headache

Myalgias

Conjunctival suffusion

± Abdominal pain and hepatosplenomegaly

Variable WBC and normal Plt

↓ Serum Na

± ↑ Serum AST, ALT, and CPK

± CSF: ↑ Leukocytes (differential: ↑ Polys or lymphocytes)

Severe cases: ↑ T. bili and ↓ albumin

What is the diagnosis?

Answer 305

eptospirosis.

Explanation

The big clue is the buzz phrase “conjunctival suffusion.” Few infectious diseases do this, and always consider lepto when you see it or see the buzz phrase. The association with Hawaii is important, as that state has the most lepto cases/year (~ 50% of all U.S. cases). Also, think about lepto if the case presents meningitis in a triathlete who swam in open water.
Dx: Culture of clinical specimens (blood, urine, CSF) + 4-fold rise in acute and convalescent IgG and IgM serum titers.
Tx: PCN or doxycycline.

Question 306

Healthy patient with 2–3 day h/o malaise, fever, and headache presents with rapidly progressive:

Cough and hypoxemia

Confusion

↓ BP, ↑ PR, ↑ RR

CXR: Widened mediastinum

CSF: ↑ Leukocytes and protein, ↓ glucose; Gram stain: Large gram-positive rods resembling “box cars”

What is the diagnosis?

Answer 306

inhalation anthrax.

Explanation

The initial pulmonary presentation followed by sepsis is consistent with any severe community-acquired pneumonia (such as Legionella, influenza with or without secondary bacterial pneumonia, tularemia, plague, or hantavirus). However, the widened mediastinum (enlarged mediastinal nodes) and subsequent meningitis are clues to inhalation anthrax.
Dx: Gram stain and culture of sputum, blood, pleural fluid CSF. PCR testing is also available.
Tx: Empiric because cultures take too long, and infection is deadly; intravenous ciprofloxacin + imipenem, rifampin, vancomycin, penicillin, ampicillin, chloramphenicol ± clindamycin.

Question 307

Hunter from Illinois presents with:

Chronic cough productive of purulent sputum

Weight loss

CXR: Several nodular lesions

Sputum with normal flora on routine culture

What is the diagnosis?

Answer 307

lastomycosis.

Explanation

In this script, we left out the yeasts. The chronicity and the association with hunting and the Midwest are good clues to the diagnosis.
Dx: Identification of the yeast in clinical specimens + culture; serologic tests are not reliable.
Tx: Mild-to-moderate disease: Itraconazole; severe or CNS disease requires amphotericin B.

Question 308

Several patients who swim at the same local swimming pool develop:

Acute, self-resolving, watery diarrhea

Crampy abdominal pain

Stool O&P: No ova or parasites

Stool modified acid-fast: 4–6 micrometer pink cysts

What is the diagnosis?

Answer 308

Cryptosporidium.

Explanation

The size of Cryptosporidium cysts are 4–6 micrometers on modified acid-fast stain. Patients with HIV/AIDS can have protracted diarrhea, weight loss, and biliary tract disease. But, immunocompetent patients who are exposed via contaminated water, such as in swimming pools, have self-limited disease.
Dx: Visualization of oocysts in clinical specimens (stool, tissue).
Tx: Treatment not necessary in immunocompetent hosts; antiretroviral treatment for HIV/AIDS patients. Nitazoxanide if requires therapy. Avoid public swimming for 2 weeks after resolution of diarrhea.

Question 309

Patient who works in a textile factory presents with:

Upper extremity skin lesion that began as an itchy, erythematous papule → central vesicle → painless, black center with significant surrounding edema

What is the diagnosis?

Answer 309

cutaneous anthrax.

Explanation

The occupational exposure and painless nature are the clues to cutaneous anthrax. There are other lesions with necrotic centers. Ecthyma gangrenosum is caused by Pseudomonas, yet occurs in neutropenic or AIDS patients who are septic. Systemic endemic fungal infections can have necrotic lesions, but there is usually infection elsewhere, typically the lung.
Dx: Gram stain and culture of the lesion. PCR testing is also available.
Tx: Empiric because culture takes too long, and infection can become systemic and deadly. Oral ciprofloxacin or doxycycline for cutaneous disease is used empirically, then can be narrowed to penicillin V or amoxicillin if susceptible.

Question 310

Adolescent patient presents with:

Fever

Pharyngeal pain ± tonsillar exudates

Marked fatigue

Anterior cervical lymphadenopathy

± Splenomegaly

↑ WBC (differential: ↑ Lymphocytes)

Peripheral smear: Atypical lymphocytes

↑ Serum AST and ALT

Heterophile antibody: Positive

What is the diagnosis? What is it due to?

Answer 310

infectious mononucleosis due to Epstein-Barr infection.

Explanation

Always think EBV mono when you see increased AST and ALT in a patient with exudative pharyngitis. Not too many other illnesses do this (Q fever does, but the case should have animal exposures). About 10% get a non-itchy maculopapular rash that lasts for ~ 1 week. Patients taking ampicillin or amoxicillin are very likely to get a morbilliform (measles-like) rash. It is fairly easy to distinguish EBV mono from GAS pharyngitis (no splenomegaly or transaminase elevation in the latter), but CMV is more difficult (less severe sore throat, but other manifestations are same; distinguished by absence of heterophile antibody and +CMV IgM serology). Primary HIV infection can look very similar to mono but would also be heterophile negative.
Dx: Clinical and of exclusion + heterophile antibody test (“monospot”) ± EBV antibodies.
Tx: Supportive; avoid contact sports until ~ 3 weeks after improvement—or even longer for aggressive contact sports.

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Question 311

Adolescent presents with the following:

Chronic anterior cervical lymph node swelling that eventually develops fluctuance ± draining sinus tract

TB skin test: > 15 mm induration

+ HIV

What is the diagnosis?

Answer 311

TB lymphadenitis (scrofula).

Explanation

Lymphadenitis due to Mycobacterium tuberculosis is historically called “scrofula.” Do not confuse that with infection with the atypical mycobacterium, M. scrofulaceum—which often causes lymphadenitis as well. Only the M. tuberculosis clinical presentation is termed “scrofula” despite the similar species name. Culture is necessary to distinguish between lymphadenitis due to TB and atypical TB, but 1 clue in this script is the induration of the TB skin test. Usually, atypical Mycobacteria do not cause positive TB skin tests, or they cause only slight induration (~ 5 mm). Most tuberculosis in HIV is reactivation of prior asymptomatic infection and occurs at the rate of 3–16% per year in patients coinfected with HIV and TB.
Dx: Excisional node biopsy with AFB smears, mycobacterial culture, and pathology (shows caseating granulomas) + CXR.
Tx: 4-drug antituberculous therapy (rifampin, INH, ethambutol, pyrazinamide) x 2 months, then 2 drugs x 4 months; duration 6–9 months.

Question 312

Patient with known heme malignancy and a central venous catheter presents with:

Fever

Blood cultures from the catheter: Gram-positive rods, identified as Corynebacterium jeikeium

What drug should be prescribed?

Answer 312

s intravenous vancomycin.

Explanation

Know that C. jeikeium is an etiology of line-associated bacteremia and sepsis, especially in patients with heme malignancies. The only effective drug is vancomycin, and it should be started immediately when you suspect this organism. This gram-positive rod should never be viewed as a contaminant even if only 1 blood culture grows.

Question 313

Hiker from Arkansas presents with:

Fever

Headache

Myalgias

↓ WBC, Hgb, Hct, and Plt

↓ Serum Na

↑ AST and ALT

What is the diagnosis?

Answer 313

ehrlichiosis.

Explanation

Think about Ehrlichia as “Rocky Mountain spotless fever” because of its similarity to RMSF, but only 30% have a rash. Like RMSF, ticks are the transmission vectors, and it predominantly occurs in the Eastern half of the U.S.
Dx: Intracytoplasmic inclusions in blood WBCs. For confirmation after treatment, 4-fold rise in acute and convalescent IgG and IgM serum titers ≥ 2 weeks apart. PCR in research settings.
Tx: Empiric doxycycline; antibiotics should not await findings of laboratory tests.

Question 314

ale patient, who lives on a goat farm, presents 2–3 weeks after assisting with the births of multiple goats with:

Fever

Headaches

Malaise

Myalgias

± Dyspnea and cough

± ↑ Serum AST and ALT

± CXR: Pulmonary infiltrates

What is the diagnosis?

Answer 314

Q fever.

Explanation

The history of exposure to birth products from livestock is your 1st clue. The organism responsible for disease is Coxiella burnetii. Know that Q fever presents with a flu-like prodrome followed by hepatitis, pneumonia, or both. Rare cases of endocarditis occur, so a clinical case could include the livestock history in a patient with culture-negative endocarditis. You might have guessed Brucella here, but remember that Brucella does not usually cause this rapid febrile response with a definite early hepatitis.
Dx: 4-fold rise in acute and convalescent IgG and IgM serum titers ± PCR in research settings.
Tx: Moderate-to-severe disease = doxycycline; endocarditis = doxy + hydroxychloroquine x 18 months.

Question 315

Patient with HIV/AIDS and a CD4 count < 100/µL presents with progressive:

Mild confusion

Right-sided motor weakness

Ataxia

Trouble initiating speech

MRI: Diffuse white matter demyelination, especially in periventricular and subcortical areas, without edema or contrast enhancement

CSF: + For JC virus by PCR

What is the diagnosis?

Answer 315

progressive multifocal leukoencephalopathy.

Explanation

Know that some patients with a PML-type clinical picture have a negative CSF PCR for JC virus. If the clinical features of PML are present in an immunosuppressed host, then do not be afraid to make that diagnosis. Remember the more recent association between PML and the use of immunosuppressant medications, such as rituximab, efalizumab, fludarabine, and chronic corticosteroids.
Dx: CSF for opening pressure, cell count, glucose, protein, JC virus DNA by PCR ± brain biopsy.
Tx: No specific antiviral therapy is available.

Question 316

Sometime after exposure to a flying bat in his camping trailer and 1 week of headaches and flu-like symptoms, a man presents with:

Anxiety and irritability

Fever

Refusal to drink water

Excessive salivation

Pharyngeal spasms in response to seeing water or feeling cold air

What is the diagnosis?

Answer 316

rabies.

Explanation

Be aware of the association of rabies with bat exposure, even if no bite was witnessed.
Dx: Immunofluorescence staining of tissue biopsy specimens + viral culture of clinical specimens (CSF, saliva, biopsies) + brain biopsy (usually postmortem).
Tx: Immediate vaccination and administration of human rabies immune globulin. Essentially 100% fatal once symptomatic.

Question 317

Young patient who is fond of snakes develops:

Fever

Bloody diarrhea

Crampy abdominal pain

Fecal leukocytes

Negative Clostridium difficile toxin assay

What is the diagnosis?

Answer 317

nontyphoidal Salmonella gastroenteritis.

Explanation

Remember the association between reptiles and amphibians and Salmonella. Eggs and contaminated poultry are also important sources. S. typhimurium and S. enteritidis are the usual species isolated in these cases. Recall that typhoid is caused by S. typhi.
Dx: Stool cultures.
Tx: Supportive; only certain patient groups merit treatment and include patients at high risk for invasive disease (infants, patients with immunodeficiencies such as HIV/AIDS) and those with severe presentation (high fevers and lots of diarrhea requiring hospitalization for volume loss). Others should not be treated because treatment prolongs the carrier state, does not affect the duration of illness, and promotes resistance. If Rx is required, use ciprofloxacin, TMP/SMX, amoxicillin, ceftriaxone, or cefotaxime.

Question 318

Patient, who did not receive any pretravel vaccinations, presents 30 days after returning from a visit to India with:

2 weeks of fever

Chills

Abdominal pain

Weight loss

Salmon-colored macular rash on the trunk

↓ HR when febrile

What is the diagnosis?

Answer 318

typhoid fever.

Explanation

The travel history, rash, and relative bradycardia are big clues to this diagnosis. The term for the rash is “rose spots,” but the script describes the rash to you instead of using the classic term. Be sure you know what rose spots look like.
Dx: Cultures of blood, stool, and rose spots. Bone marrow cultures have the highest yield. Cultures may require prolonged incubation. Susceptibility results are important.
Tx: Ceftriaxone, ciprofloxacin, or azithromycin; specific drug choice depends on extent of illness and local susceptibility patterns. Watch out for ileal perforation as a complication

Question 319

Older man with a recent h/o cystoscopy presents with days to weeks of:

Fevers and chills

Arthralgias

Weight loss

New diastolic murmur, loudest at the upper right sternal border

Blood cultures: Gram-positive cocci in chains; sensitive to penicillin, ampicillin, vancomycin, and gentamicin

What is the diagnosis?

Answer 319

nterococcal endocarditis.

Explanation

Clues in this case are the history of genitourinary instrumentation and subacute presentation of bacteremia. If the gram-positive cocci in the blood were staph, the clinical presentation would be more fulminant. You might have guessed endocarditis due to viridans streptococci, but those organisms come from the mouth and are not associated with recent history of GU manipulation. Enterococcal isolates are generally tested for susceptibility to penicillin, ampicillin, vancomycin, and aminoglycosides only.
Dx: Revised Duke criteria, which includes bacteriologic + echocardiographic findings (in this case it would show a new regurgitant murmur).
Tx: Depends on susceptibility; gentamicin + penicillin G, ampicillin, or vancomycin x 4–6 weeks, depending on duration of symptoms prior to diagnosis.

Question 320

24–48 hours after visiting the U.S. Gulf Coast and eating shrimp and crab, a patient presents with:

Fever

Bloody diarrhea

Crampy abdominal pain

What is the diagnosis?

Answer 320

ibrio parahaemolyticus.

Explanation

Vibrio parahaemolyticus is found in the same environment as other vibrios, but it presents differently from cholera, with a more inflammatory picture. Rarely, it can also cause skin and soft tissue infections, like Vibrio vulnificus.
Dx: Specialized stool cultures.
Tx: Supportive with aggressive volume resuscitation. Doxycycline or quinolones for severe disease.

Question 321

A 40-year-old male cyclist presents with repeated bouts of:

Fever

Dysuria

Perineal aching

Lower abdominal pain

Urinary hesitancy

U/A: ↑ Leukocytes, +nitrites, +leukocyte esterase

What is the diagnosis?

Answer 321

acute prostatitis.

Explanation

If this case were presented in a female, the diagnosis would definitely be cystitis or pyelo. The most common cause of recurrent UTIs in men is a prostatic focus. Cycling is a risk factor for an inflamed prostate.
Dx: Prostate exam with gentle prostatic massage with Gram stain and culture of prostatic secretions.
Tx can be empiric or based on Gram stain results: Empiric = TMP/SMX or FQ; if GPC chains = amoxicillin or parenteral ampicillin; GPC clusters = cephalexin, dicloxacillin, or parenteral cefazolin or nafcillin.

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17th Ed. IM Core Curriculum : Book 1 : ID > Urinary Tract Infections > Prostatitis

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Known diabetic patient with poor dental hygiene presents with:

Chronic, painless swelling at the angle of the jaw that develops a draining sinus, extruding yellow, gritty material

Gram stain of gritty material: Branching, filamentous, gram-positive rods

What is the diagnosis?

Question 322

Known diabetic patient with poor dental hygiene presents with:

Chronic, painless swelling at the angle of the jaw that develops a draining sinus, extruding yellow, gritty material

Gram stain of gritty material: Branching, filamentous, gram-positive rods

What is the diagnosis?

Answer 322

ervicofacial actinomycosis (“lumpy jaw”).

Explanation

When the presentation is early, before any fistulae form and before any sulfur granules (the gritty yellow exudate) are extruded, the diagnosis is sometimes difficult and is often misdiagnosed as a cellulitis. The disease is called lumpy jaw for a reason; always consider it in anybody who develops a lump in the jaw area. Pelvic and intraabdominal actinomycosis are associated with the use of IUDs, so think about actino in any IUD-related abdominopelvic presentation.
Dx: Gram stain and culture of clinical specimens + biopsies (inflammation, fibrosis, and sulfur granules). Actinomyces can be differentiated from Nocardia because Nocardia is partially acid-fast and an aerobe whereas Actinomyces is not acid-fast and is an anaerobe.
Tx: High-dose oral penicillin or ampicillin; 2nd choice is tetracycline.

Question 323

Adolescent patient with no respiratory symptoms develops acute onset of:

Pharyngeal pain with tonsillar swellings and exudate

An erythematous, sandpaper-like, desquamating rash that spares a circular area around the mouth

Strawberry tongue

Petechial lines that concentrate in the antecubital fossa, axilla, and groin

What is the diagnosis?

Answer 323

carlet fever.

Explanation

Key words for scarlet fever are “circumoral pallor” (the pale area around the mouth), “Pastia lines” (petechial lines in the skin creases), and “desquamation.” Arcanobacterium pharyngitis can present with this same scarlatiniform rash but lacks Pastia lines and desquamation. Enteroviral pharyngitis may have a rash, but it is vesicular/pustular. EBV pharyngitis may have a diffuse rash but would not have Pastia lines.
Dx: Rapid strep test; throat cultures are no longer recommended in adults, even when the rapid test is negative.
Tx: Oral penicillin V; amoxicillin, 1st generation cephalosporins, and IM PCN G are alternatives.

Question 324

Gardener presents with:

Chronic papulonodular skin lesion on the hand or forearm

Smaller papular lesions in proximal lymph channels

What is the diagnosis?

Answer 324

sporotrichosis.

Explanation

This diagnosis, in this current form, is probably too easy for an exam. However, remember that alcoholics, diabetics, and patients with HIV/AIDS may present with disseminated sporo that presents as hypotension and pneumonia.
Dx: Fungal stains and culture on clinical specimens (aspirates, tissue biopsies, body fluids) ± biopsy (may show small number of fungal organisms with special stains).
Tx depends on extent of disease: For disease limited to the lymph system and skin = oral itraconazole; severe disease = lipid amphotericin B then transition to itraconazole after improvement.

Question 325

1 week after returning from a road trip through Arizona and New Mexico, a previously healthy female patient presents with:

Fatigue

Fevers

Cough

Arthralgias

Tender nodules across both shins

What is the diagnosis?

Answer 325

primary Coccidioides infection.

Explanation

The clues here: Arizona and description of erythema nodosum. This presentation is “Valley Fever.”
Dx: Fungal stains and culture of clinical specimens + IgG and IgM serum immunoassays.
Tx: No treatment required for mild disease; less severe illness, treat with fluconazole; severe illness, immunosuppression. Pregnant patients should be treated with amphotericin B.

Question 326

Valley fever

Answer 326

Coccidio

Question 327

Young patient who stepped on a nail while wearing tennis shoes presents with:

Fever

Extensive soft tissue pain and swelling at puncture site

↑ ESR

What is the diagnosis?

Answer 327

Pseudomonas aeruginosa cellulitis.

Explanation

P. aeruginosa survives in the moisture-absorbing middle layer of tennis shoes and can be inoculated into soft tissue or bone after stepping on nails.
Dx: Culture.
Tx: Oral or IV drug depends on extent of sickness and organism’s susceptibilities. The only oral drugs are quinolones; parenteral choices include ceftazidime, cefepime, imipenem, gentamicin, tobramycin, ciprofloxacin, aztreonam, piperacillin/tazobactam, or ticarcillin/clavulanic acid. For very sick individuals, typically 2 antipseudomonal drugs are used with 1 from each of following categories: antipseudomonal beta-lactams + either aminoglycoside or quinolone.

Question 328

Previously healthy adolescent presents with the acute onset of:

Fever

Seizure

Confusion

CSF: ↑ Leukocytes (↑ lymphs),↑ RBCs, ↑ protein

MRI: Temporal lobe enhancement

What is the diagnosis?

Answer 328

erpes simplex encephalitis.

Explanation

The big clues to this case are: Bloody CSF and temporal lobe enhancement; both are cardinal features of HSV encephalitis. Other forms of encephalitis uncommonly present with the hemorrhagic component and the temporal lobe involvement.
Dx: Brain imaging + CSF for cell count, protein, glucose, HSV DNA by PCR (gold standard test), and viral culture ± brain biopsy for atypical cases.
Tx: Intravenous acyclovir x 14–21 days.

Question 329

Patient with h/o acute leukemia, neutropenia, and fever has:

Persistent fever after empiric treatment with ceftazidime

Indwelling central venous catheter that appears uninfected

Blood cultures: Gram-positive cocci

What is the diagnosis?

Answer 329

staphylococcal bacteremia.

Explanation

The objective of this case is to suspect staphylococcal bacteremia in a patient with febrile neutropenia, a central line, and failure to respond to ceftazidime. Ceftazidime is less active than 1st or 2nd generation cephalosporins against MSSA and is inactive against MRSA. Other common gram-positive cocci (such as strep) are covered reasonably well by ceftazidime. Without specific clues, it is reasonable to assume that this neutropenic patient has 1 of the more common causes of fever; e.g., the venous catheter.
Dx: Blood cultures.
Tx: Vancomycin, then narrow coverage based on susceptibility test results.

Question 330

Several months after a trip to Martha’s Vineyard, a patient presents with:

Chronic (weeks to months), mildly painful, very swollen knee

Large knee effusion

+Serum RPR

+B. burgdorferi IgG and IgM ELISA

+B. burgdorferi Western blot

Arthrocentesis: WBC < 25,000/mm3

What is the diagnosis?

Answer 330

Lyme arthritis.

Explanation

Positive antibody tests, in and of themselves, are not enough to make a diagnosis of Lyme disease. However, in the appropriate clinical context, order a Western blot test to confirm the ELISA results. Remember that Lyme can be associated with a false-positive RPR.
Dx: 2-stage Lyme testing (IgM and IgG ELISA or IFA screening with confirmation of positive tests using Western blot) ± PCR testing for B. burgdorferi on joint fluid.
Tx: Oral doxycycline or amoxicillin x 30 days; some patients with persistent symptoms require parenteral treatment with 30 days of ceftriaxone. After 30 days of parenteral treatment with ceftriaxone, manage symptoms with analgesics only.

Question 331

Injection drug user, who mixes his heroin with prepackaged lemon juice from the grocery store, presents with:

Fevers

Decreased vision

Blood cultures: Yeast

What is the diagnosis?

Answer 331

Candida fungemia and endophthalmitis.

Explanation

Contaminated diluents have been associated with fungemia in injection drug users, especially the premade lemon juice available at the grocery store. Look for Candida fungemia in the patient with a history of a long-term indwelling central venous catheter, especially if also receiving TPN. Eye disease is a frequent complication of fungemia, and all patients with Candida fungemia should have funduscopy because eye disease affects the duration and type of treatment with antifungal drugs.
Dx: Clinical, including ophthalmologic exam + blood cultures ± fungal stain and cultures of vitreous ± β-d-glucan assay (most helpful in intraabdominal candidal infections that are associated with negative blood cultures).
Tx: Depends on species of Candida that is isolated and whether the species is susceptible to fluconazole; also depends on extent of ocular involvement. Agents used include amphotericin B, liposomal amphotericin, echinocandins, fluconazole, or voriconazole ± vitrectomy.

Question 332

Elderly patient presents with acute onset:

Confusion

Fever

↑ WBC

CSF: ↑ Leukocytes > 100/hpf (polys, lymphs, and monos), ↑ protein, ↓ glucose, Gram stain: No organisms

Blood cultures: + Gram-positive rods

What is the diagnosis?

Answer 332

Listeria meningitis.

Explanation

Recognize that the CSF Gram stain often does not show organisms in patients with Listeria meningitis, but this script shows evidence of meningeal involvement because of the CSF pleocytosis and increased protein. The specific clues in this case are confusion, elderly person, and CSF pleocytosis. Remember that gram-positive rods comprise Listeria.
Dx: CSF for glucose, protein, cell count with differential + culture or organism from blood or CSF.
Tx: Either ampicillin or penicillin G. Gentamicin often added for synergy, but no studies available to assess additional efficacy.

Question 333

Homeless person presents with:

Fever

Chills

Headache

Weakness

Dyspnea and cough

Pleuritic chest pain and hemoptysis

Confusion

Pain and swelling in an inguinal lymph node

CXR: Diffuse pulmonary infiltrates

What is the diagnosis?

Answer 333

pneumonic plague.

Explanation

The important fact to remember about pneumonic plague is that it is highly contagious, even though the bubonic form (from which this script developed) requires the vector for transmission. Make sure to recognize the bubo in the script!
Dx: Gram stain and culture of clinical specimens for Yersinia pestis (blood, sputum, CSF, lymph node aspirates) or Wright stain of peripheral blood (may show safety pin-shaped organisms) or 4-fold rise in acute and convalescent IgG and IgM serum titers ± PCR or ELISA testing on specimens in research settings.
Tx: Streptomycin; 2nd line choices are tetracycline or quinolones + respiratory isolation.

Question 334

atient with HIV/AIDS and a CD4 count < 100/µL presents with:

Headache

Vomiting

Seizure

Contrast head CT: Multiple ring-enhancing lesions and generalized edema

Serum toxo IgM negative, IgG positive

What is the diagnosis?

Answer 334

Diagnosis is cerebral toxoplasmosis.

Explanation

Remember that CNS toxo is usually a reactivation disease, so patients are usually positive for antitoxo IgG. But not always! If the patient has ring-enhancing brain lesions and immunosuppression (and no other obvious diagnosis), you can empirically diagnose toxo even if the serum IgG is negative. Remember that herpes encephalitis and brain abscesses usually result in only a single lesion, but toxo presents with multiple lesions.
Dx: Brain imaging + IgM and IgG toxo antibodies ± brain biopsy (shows organisms on special stains) ± CSF for PCR at research institutions.
Tx: Pyrimethamine + sulfadiazine + leucovorin.

Question 335

Previously healthy menstruating female presents 3 days into her menstrual cycle with:

Fever and rigors

Headache

Diarrhea ± abdominal pain and vomiting

↓ BP

Mucosal hyperemia

Diffuse erythroderma

Nonpitting edema

↑ or ↓ WBC

Differential: ↑ Neutrophils and band forms

↓ Hgb, Hct, and Plt

± ↓ Serum Na, albumin, Ca, and PO4

± ↑ Serum AST and ALT, creatinine, and CPK

Blood cultures: No growth

What is the diagnosis?

Answer 335

staphylococcal toxic shock syndrome (TSS).

Explanation

Exam questions regarding TSS commonly present a patient with overwhelming sepsis in the context of a menstruating female or a postsurgical wound infection. The CDC definition of TSS is easy to remember and includes the triad of shock, fever, and rash, along with involvement of ≥ 3 organ systems. Blood cultures in staph TSS are usually negative, but positive in strep TSS. Epidemiology is important in making a diagnosis in this case. This is 1 of the few infections that will take a young person from healthy to deathly sick in only a couple of days. You might have suspected RMSF or meningococcemia, both of which can also cause severe disease in otherwise healthy young people, but neither presents with erythroderma. With RMSF, the history would include tick exposure and would describe a petechial rash. With meningococcemia, the history might include meningeal signs and describe petechiae and purpura. There is no special association between menstruation and RMSF or meningococcemia. You also might have suspected scarlet fever because you saw erythroderma. Recognize that scarlet fever is due to streptococcal pharyngitis, and this patient does not have a sore throat.
Dx: Clinical: CDC case definition of rash.
Tx: Supportive care + surgical drainage of pus if present + vancomycin and clindamycin.

Question 336

omeless person presents with:

Fever

Chills

Headache

Weakness

Pain and swelling in an inguinal lymph node with overlying erythema

Nodal aspirate: Gram stain shows gram-negative bacilli and cocco-bacilli

What is the diagnosis?

Answer 336

bubonic plague.

Explanation

This form of plague is transmitted via rodent fleas, so patients who have exposure to rodents may become infected. The inguinal bubo, and its Gram stain, are the biggest clues to diagnosis in this case. Sometimes Yersinia may grow in blood cultures, and organisms may be described as having a “safety pin” appearance in addition to bacilli or cocco-bacilli.
Dx: Gram stain and culture of clinical specimens (blood, sputum, CSF, lymph node aspirates) or Wright stain of peripheral blood (may show safety pin-shaped organisms) or 4-fold rise in acute and convalescent IgG and IgM serum titers ± PCR or ELISA testing on specimens in research settings.
Tx: Streptomycin; 2nd line choices are tetracycline or quinolones.

Question 337

60-year-old East Texas patient sits for hours in his front yard in the summertime. He presents with fever, severe headache, and myalgias, then develops:

Confusion

Tremors of eyelids, tongue, lips, and extremities

Myoclonus

± Unilateral facial weakness

↑ Serum AST, ALT, and CPK

↓ Serum Na

CSF: ↑ Leukocytes (< 200 cells/mm3) with ↑ monocytes, mild ↑ protein, normal glucose; Gram stain: No organisms; –HSV PCR

MRI: No abnormalities

Answer 337

rbovirus encephalitis.

Explanation

This case would most likely be St. Louis encephalitis, but most of the etiologies have similar presentations. Think about arbovirus encephalitis when you see altered mental status with tremors and clonus. The epidemiologic clue is that the patient sits outside in the summer where mosquitos linger.
Dx: Clinical and of exclusion (especially exclude HSV with CSF PCR) + CSF opening pressure, cell count, protein, glucose, viral culture, PCR for arboviruses (gold standard test) + serum and CSF for arboviral antibodies.
Tx: Supportive.

Question 338

Bovine rancher with a known bicuspid valve develops:

Prolonged fevers

Scattered lymphadenopathy

Hepatosplenomegaly

New diastolic murmur at the left upper sternal border

Increased CRP

Several sets of negative blood cultures

Echo: Aortic vegetation with regurgitation

Negative Coxiella serology

What is the diagnosi

Answer 338

rucella endocarditis.

Explanation

Brucella and Coxiella are both causes of culture-negative endocarditis.
Dx: Revised Duke Criteria, which includes bacteriologic (Gram stain and culture of clinical specimens [blood, valve, marrow aspirate, liver biopsy]) + echocardiographic findings. Brucella can be diagnosed by a 4-fold rise in acute and convalescent IgG and IgM serum titers ≥ 2 weeks apart or positive titer > 1:80 in nonendemic areas ± PCR in research settings. Coxiella causing chronic Q fever can be diagnosed by an IgG titer of > 1:800.
Tx: Doxycycline + streptomycin or gentamicin ± rifampin

Question 339

Young patient with h/o splenectomy develops fever and:

Rigors and confusion

↓ BP and ↑ HR

Petechiae and purpura

↓ WBC, Hgb, Hct, and Plt

Differential: ↑ Neutrophils and band forms

Peripheral smear: Dohle bodies and toxic granulations

↑ AST, ALT, and serum creatinine

Prolonged PT and PTT

↑ D-dimer and fibrin degradation products with ↓ fibrinogen

Buffy coat: Gram-positive diplococci

What is the diagnosis?

Answer 339

pneumococcal sepsis.

Explanation

The history of splenectomy should cause you to consider encapsulated bacteria as a cause of sepsis. Fulminant pneumococcal disease is the most common cause of sepsis in the splenectomized patient, and it can present with DIC. Sometimes no source is obvious. The clinical scenario may or may not give you “gram-positive, lancet-shaped diplococci” as a clue.
Dx: Blood cultures ± urinary pneumococcal antigen.
Tx: Vancomycin (in splenectomy patient) + either ceftriaxone or cefotaxime, then narrow coverage based on susceptibility results.

Question 340

Approximately 2–3 weeks after obtaining a new kitten, patient presents with:

Fever

Papular lesion on the forearm, present for ∼ 1 week

New painful axillary lymphadenopathy

What is the diagnosis?

Answer 340

cat scratch disease.

Explanation

Cat scratch disease is caused by Bartonella henselae. Bartonella species can cause systemic disease in patients with HIV/AIDS.
Dx: Clinical and of exclusion (exclude other bacterial causes of lymphadenitis, especially atypical mycobacteria and scrofula) + serologic test for B. henselae with ≥ 1:64 titer ± biopsy of lesions with granulomatous inflammation on pathology and organisms visible on Warthin-Starry stain.
Tx: Self-limited, so usually no treatment required, and antibiotic use in lymphadenitis is controversial; if prescribing, give azithromycin. Treat rare cases of dissemination to eye, liver, or CNS with azithromycin.

Question 341

Elderly male with h/o BPH presents with:

Scrotal pain

Tenderness limited to the posterior side of the testis with epididymal induration

Intact cremasteric reflex

U/A: ↑ WBCs

Urine culture: + E. coli

What is the diagnosis?

Answer 341

infectious epididymitis.

Explanation

This diagnosis in an older male is more often caused by enteric gram-negative rods than by sexually transmitted infections, which is what you would consider if the patient were
< 40 years of age (gonorrhea and Chlamydia). This is not torsion because the presentation is subacute, the physical exam does not show pain across the entire testis, and the cremasteric reflex is present.
Dx: Urinalysis + urine culture ± urethral swab of Gram stain and gonorrhea culture and urine for nucleic acid amplification based on risks for STIs.
Tx: Ceftriaxone 250 mg IM + doxy + FQ if ≥ 35 years of age or if practices insertive anal intercourse; severe presentation should be referred to urologist immediately.

Question 342

approximately _% of patients presenting to the emergency department with white-cell counts of 12,000 to 25,000 cells have noninfectious conditions

Answer 342

50

Lawrence YR, Raveh D, Rudensky B, Munter G. Extreme leukocytosis in the emergency department. QJM 2007;100:217-223.