ID Flashcards

1
Q

MC etiologies of meningitis?

A
  • bacterial:
    strep pneumo
    N. meningitidis
    H. flu
  • viral: enteroviruses, HSV, HIV, West Nile, VZV, mumps
  • fungal: cryptococcus
  • noninfectious: tumor, trauma, brain abscess, subdural empyema, pharm rxn
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2
Q

Community acquired vs health care assoc etiologies of meningitis?

A
- community:
Strep pneumo
N. meninigitis
H flu
Listeria monocyotgenes (immune compromised)
  • healthcare:
    staph and aerobic gram neg bacilli
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3
Q

Sxs of meningitis?

A
  • abrupt onset
  • classic triad: fever, nuchal rigidity, change in mental status
  • intense HA
  • photophobia, lethargy, nausea, vomiting, jt pain, seizures
  • mediation duration of sxs b/f presentation: 25hrs (bacterial)
  • petechial rash = N. Meningitidis
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4
Q

Dx issues w/ CNS infections in elderly?

A
  • hard to initially separate meningitis from encephalitis:
    both present w/ mental status changes, elderly w/ meningitis less likely to have fever
  • any infection in elderly can cause delirium in elderly
  • if personality change think encephalitis
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5
Q

What are red flags in elderly pop when thinking about meningitis?

A
  • behavioral changes/personality changes
  • seizures
  • lack of there source of infection
  • HA, nuchal rigidity, exposure to infected persons
  • low threshold to do LP
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6
Q

Indications for head CT prior to LP?

A
  • immunocompromised
  • hx of seizure w/in 1 wk prior to presentation
  • any of following neuro abnorm:
    abnorm LOC
    hx of CNS disease (lesion, stroke, focal infection)
    PAPILLEDEMA
    focal neuro deficit
  • mandatory in pts w/ possible focal infection
    ** any evidence of papilledema or focal neuro findings - don;t perform LP b/f getting STAT CT to r/o sig ICP
  • perform LP immediately in absence of papilledema or focal neuro findings
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7
Q

W/U for meningitis? Tx?

A
  • blood cultures, CBC, chem 7
  • send CSF to lab for cell count, gram stain, culture, glucose, and total protein:
    Any + gram stain is dx, WBC in CSF over 1000 if PMNs make up 85% is dx, CSF glucose less than 50% of serum glucose is suggestive
  • as soon as LP is completed (b/f labs are even back) give 2 gm rocephin IV
  • all admitted and rocephin cont at 2 G IV q 12 hrs
  • many even w/ proper, rapid tx will die or have permanent CNS deficits
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8
Q

Normal CSF values?

A
  • pressure: 70-180 mm H2O
  • appearance: clear, colorless
  • CSF total protein: 15-45 mg/100 ml
  • CSF glucose: 50-80 mg/100 ml (or greater than 2/3 of blood sugar level)
  • CSF cell count: 0-5 WBCs (all mononuclear) and no RBCs
  • chloride: 110-125 mEq/L
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9
Q

Bacterial meningitis clues in peds?

A
  • occurs MC b/t 2 mo- 2 yrs
  • uncomon to develop meningitis form OM and spread is not from direct extension but from systemic spread
  • irritability and poor feeding may be only clues in infants
  • paradoxical irritability: crying worsens when being held - suggestive of meningitis
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10
Q

MC etiologic agents of meningitis in peds pts? How can we prevent this?

A
  • strep pneumo
  • N. meningitidis
  • H flu
  • in neonates: consider gram - causes, group B strep
  • primary prevention of meningitis:
    S. pneumo vaccine
    H. flu vaccine
    Meningococcal vaccine now available for teens and adults
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11
Q

What is menigoencephalitis?

A
  • overlap of meningitis + encephalitis
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12
Q

What is encephalitis? MC etiology?

A
  • inflammation of the brain
  • MC caused by viral infections:
    HSV-1, HSV-2 are rapidly progressing and life threatening
  • West Nile, CMV, mumps, EBV
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13
Q

What is the diff b/t encephalitis and meningitis?

A
  • encephalitis has alt brian fxn and neuro findings: personality changes, paralysis, hallucinations, alt smell, problems w/ speech
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14
Q

Sxs of encephalitis?

A
  • mild: flu like sxs
  • severe:
    severe HA, fever, alt consciousness, confusion, agitation, personality changes, seizures, loss of sensation, paralysis, muscle weakness, hallucinations, double vision, perception of foul smells, problems w/ speech or hearing, LOC
  • children: bulging of fontanels, N/V, body stiffness, inconsolable crying, crying that worsens when picked up, poor feeding
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15
Q

W/U and tx of encephalitis?

A
  • CT and/or MRI of head
  • CBC, CMP
  • LP: usual cultures, PCR for HSV1, serology: IgM ab for west nile virus, mumps, EBV
    note if RBCs in CSF and nontraumatic tap it is HSV until proven otherwise
  • tx: Acyclovir 10 mg/kg IV q 8 hrs (empiric tx for HSV b/c it is most deadly)
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16
Q

Septic arthritis progression? What jts are most commonly affected?

A
  • It is an emergency!!
  • when left untx - can destroy a jt in 12-24 hrs
  • usually affects only one or few asymmetrical jts
  • more commoly affects large jts, esp knee
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17
Q

S/S of septic arthritis?

A
  • acute or subacute onset of pain
  • erythema, swelling and limiting jt motion
  • systemic sx (fever, malaise) may be present or absent
  • Must do arthrocentesis on any: red, hot, swollen jt
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18
Q

What will jt fluid analysis show in septic jt tap?

A
  • over 40,000 WBCs in most cases
  • send jt fluid for crystals, glucose, cell count, culture
  • have to specific culture + sensitivity + r/o gonorrhea
  • gram stain of jt fluid will show causative organism in most cases except gonoccal arthritis (80% false negative)
  • if GC arthritis is suspected in sexually active pt: do cervical, urethral, or rectal GC cultures as approp for over 90% sensitivity
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19
Q

Tx for septic arthritis?

A
  • High dose IV abx
  • no indication for intra-articular abx
  • Rocephin good choice
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20
Q

Sxs of bacteremia? Source of infection?

A
  • fever, +/- chills, rigors may suggest bacteremia, disorientation, hypotension, resp failure, sepsis, septic shock, skin lesions
  • source of infection: resp tract, central venous cath, urinary tract, GI tract, biliary tract, skin, soft tissues
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21
Q

Tx for gram - bacteremia?

A
  • 25-50% of all blood stream infections (worse off than gram +)
  • tx for severe sepsis +/- shock:
    gentamicin or tobramycin or amikacin + antipseudomonal cephalosporin like cefepime +/- vanco until cultures come back
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22
Q

Tx for gram + bacteremia?

A
  • staph aureus leading cause
  • empiric tx: vanco
  • MSSA: PCN, nafcillin, oxacillin, vanco
  • MRSA: vanco or daptomycin
  • w/u should include TEE to r/o infectious endocarditis (IV drug use hx)
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23
Q

What is sepsis?

A
  • clinical syndrome from dysreg inflammatory response to an infection
  • infection + some of the following:
    temp greater than 38.3, or less than 36C
    HR over 90
    RR over 20
    AMS
    sig edema
    hyperglycemia w/o hx of DM (glucose over 140)
    or
  • infection + some of the following:
    inflammatory: WBC over 12K, or below 4K, WBC w/ over 10% of bands, elevated CRP, elevated procalcitonin
  • hemodynamic:
    hypotension often w/ wide pulse pressure
  • poor urine output, elevated creatinine, elevated INR, and PTT, low platelets
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24
Q

Another definition of sepsis?

A
- infection + some of the following:
ileus
elevated bili
elevated lactate
decreased cap refill
arterial hypoxemia
25
Q

Tx of sepsis?

A
  • supportive and tx most likely source of infection such as bacteremia
26
Q

What is cellulitis? When is it considered an emergency? Tx?

A
  • superficial soft tissue infections are rarely emergencies w/ 3 exceptions:
    infection around face and hand, cellulitis in presence of diabetes or PVD, local infection w/ presence of leukemia or HIV
  • cellulitis: acute spreading infection of skin to and through dermis
  • all cellulitis, folliculitis, furnuculosis is due to MRSA until proven otherwise, DOC is bactrim and alt = clinda
27
Q

What is impetigo? Tx?

A
  • superficial skin infection usually seen in kids due primarily to strep, uncommonly staph
  • small vesicles which quickly ruptures and form honey colored crusts
  • tx: bactroban
28
Q

What is endocarditis?

A
  • infection of endothelial surface of heart, most often the valves
  • tough to dx
  • may present as acute or subacute
  • pts at high risk are those w/ previous valve damage, replacement, or hx of IVDU
  • subacute may present w/ anorexia, night sweats and wt loss
  • acutely: cardiac failure, stroke due to septic emboli, or cold extremity due to septic emboli
  • IVDU: may have tricuspid valve endocarditis and may present w/ bilateral embolic pneumonia
29
Q

What are characteristic but not specific cutaneous lesions of endocarditis?

A
  • conjunctival and palatal petechiae
  • subungual (splinter) hemorrhages
  • osler nodes = tender, erythematous nodules w/ opaque centers which appear on pulp of fingers/toes
  • janeway lesions: nontender red or maroon macules or nodules on palms and soles
  • dilated eye exam: roth spots (pale oval areas surrounded by hemorrhage) near optic disc
30
Q

Dx tests for endocarditis?

A
  • echo: may show valvular vegitation TEE better than TTE
  • normocytic, normochromic anemia may be present
  • elevated ESR almost always present
  • obtain blood cultures and start empiric abx
31
Q

What is TSS?

A
  • results from absorption of toxin from localized staph aureus colonization or infection:
    hx - tampon use, increasing number of cases now seen from wound or sinus infections
32
Q

S/S of TSS?

A
  • short prodrome: fever, myalgias, V/D, pharyngitis
  • rapidly develop fulminate shock (SBP less than 80 mmHg) and fever over 102.2 w/ mult organ failure
  • a diffuse blanching, macular erythema appears w/ signs of pan-mucosal inflammation, rash fades in 2-3 days, desquamation of hands and feet occurs in all 5-12 days after rash disappears
33
Q

Labs for TSS?

A

nonspecific but represent mult organ system involvement:

  • leukocytosis, thrombocytopenia (bone marrow toxicity)
  • elevated BUN and Cr (renal toxicity)
  • elevated LFTs and bili (liver toxicity)
  • sterile pyuria
  • elevated CPK (muscle damage)
  • decrease serum albumin and total protein due to leaking caps
  • blood cultures: will be negative and this is toxin induced
  • cultures of source: vagina, wound or sinus: will grow S. aureus
  • max supportive care and tx to prevent additional toxin production
34
Q

Presentation of RMSF?

A
  • incubation 1 wk
  • sudden onset of fever, chills, malaise, myalgias, severe frontal HA
  • on the 2nd-5th day: rash appear - pink, macular 1-4 mm in diameter appears on palms, soles, hands feet, wrists and ankles
  • over next 24-48 hrs becomes petechial, purpuric, and even gangrenous
  • **spreads centripetally
  • diffuse edema due to cap leakage, hypotension, splenomegaly, and delirium
  • labs may all be normal
  • tx: early TCN or doxy (kids: chloramphenicol)
35
Q

Stages of Lyme disease?

A
  • stage 1: rash = erythema migrans, gradually expanding area of redness w/ central clearing from bite site, may be accomp by fever, chills, malaise, regional adenopathy
  • stage 2: days to weeks after infection, multisystem involvement (heart, liver, neuropathy, muscular), fatigue, lethargy may persist for months
  • stage 3: lingers for months to yrs w/ arthritis, neuropathy, acrodermatitis chronica atrophicans
  • only lab proof is rising titer seen in paired sera
  • best approach is empirical tx: Doxy!!
36
Q

Sxs of malaria?

A
  • parasitic infection secondary to plasmodium falciparum (90% of cases)
  • sxs occur 12-35 days after exposure and can wax and wane due to parasite load
  • uncomplicated cases, sxs: fever, malaise, myalgias, arthralgias, HA
  • fevers may be predictable and occur at regular intervals (cyclical fever)
  • complicated cases: fever, anemia, splenomegaly, alt consciousness, seizures, ARDS, circulatory collapse, metabolic acidosis, renal failure, liver failure, coagulopathy, DIC, severe anemia, intravascular hemolysis, hypoglycemia
  • sxs: can progress rapidly and can be fatal
  • PE: pallor, petechiae, jaundice, hepatomegaly, splenomegaly, splenic rupture
37
Q

Dx malaria?

A
  • anemia, elevated WBC, low platelets
  • dx is clinical and based on parasite dx w/ either giemsa stained visualization of parasites in periph blood smear, antigen or ab tests, molecular techniques for extracting parasite genetic material
38
Q

Tx of malaria?

A
  • depends on location where infection was acquired

- chloroquine, quinine, doxy

39
Q

Describe botulism?

A
  • it is in soils and marine sediment worldwide
  • gram +, rod shaped, spore forming obligate anaerobic bacteria
  • 5 forms:
    foodborne, infant, wound, adult enteric and inhalation
40
Q

Key features of botulism?

A
  • classically described as acute onset of bilateral cranial neuropathies assoc w/ symmetric descending weakness
  • other key features:
    absence of fever, pt remains responsive, normal or slow HR and norm BP, no sensory deficits w/ exception of blurred vision
41
Q

Testing for botulism?

A
  • infants: neg in serum, eval stool for spores and toxin
  • foodborne: serum analysis for toxin
  • wound: cultures of wound should be +, likely negative serum assays
  • adult enteric: eval stool for spores and toxin
42
Q

Tx of botulism?

A
  • any s/s or hx suspicious for botulism should be hosp immediately and monitored for signs of resp failure
  • 2 botulism-a antitoxin therapies:
    equine serum heptavalen bolulism antitoxin (older than 1 yo)
    or
    botulism immune globin for infants (younger than 1)
  • abx are only helpful for wound botulism: PCN G and metronidazole
43
Q

Epidemiology of smallpox?

A
  • only disease known to be eradicated
  • droplet, contact, airborne transmission from person to person
  • doesn’t occur until onset of rash
  • max infectiousness: days 7-10 of rash
  • increased infectiousness if pt coughing or has hemorrhagic form
  • anyone under 26 has no immunity
  • vaccine b/f or w/in 2-3 days of exposure over 99% effective
  • spreads more readily during cool, dry winter
  • variola (family poxviridae) - part of orthopoxviruses (including chickenpox)
  • humans only reservoirs
44
Q

Clinical features of smallpox?

A
  • incubation period: 12 days (7-17 days)
  • non-specific prodrome (2-4 days) of fever, myalgias
  • rash most prominent on face and extremities (including palms and soles) in contrast to truncal distribution of varicella
  • rash scabs at 1-2 wks
  • variola rash has synchronous onset (in contrast to varicella - comes in crops)
45
Q

Dx of smallpox?

A
  • rash
  • hemorrhagic smallpox may be mistaken for meningococcemia or severe acute leukemia
  • culture of lesions
  • should be obtained by immunized person, place specimen in vacutainer tube, tape juncture of stopper and tube, place in second durable watertight container
  • alert lab!
46
Q

Disease course of smallpox?

A
  • day 12-14: fever, malaise, non-prod cough, HA, backache, jt pain
  • 14-16: papular rash on face and extremities
  • 16-18: papular rash w/ vesicular and pustular lesions
  • 22-26: crusted lesions
  • 28-30: resolving
  • 10% will develop malignant disease and die 5-7 days after incubation
47
Q

control of smallpox?

A
  • clothing/fomites: decontaminate
  • prophylaxis
  • pre-exposure: vaccine
  • post-exposure: vaccine w/in 4 days or vaccine + VIG (if past 4 days), potential use of cidofovir (antiviral agent)
  • isolation: contact + airborne
48
Q

diff b/t variola and varicella?

A
  • variola: rash starts on face, lesions all same stage, deep lesions, often palms and soles affected, centrifugal rash, back more than abdomen, mulitloculated vesicles
49
Q

Dx testing for smallpox?

A
  • r/o other vesiculating dz

- when in doubt: quarantine/isolate

50
Q

Tx of smallpox?

A
  • supportive
  • must isolate and immunize contacts
  • Cidofovir tx may help
  • mortality is age dependent and ranges from 30-95%
51
Q

What is anthrax? 3 clinical forms?

A
  • caused by spore forming bacterium, Bacillus anthracis
  • human infection typically acquired through contact w/anthrax infected animals or animal products or atypically through intentional exposure
  • forms:
    cutaneous
    inhalational
    GI
52
Q

Clinical course of anthrax?

A
  • begins as papule, progresses through vesicular stage to depressed black necrotic ulcer (eschar)
  • edema, redness, and or necrosis w/o ulceration may occur
  • form MC encountered is naturally occurring
    -incubation: 1-12 days
  • case fatality: w/o abx - 20%
    w/ abx - 1%
53
Q

DDx of cutaneous anthrax?

A
  • spider bite
  • Ecthyma gangrenosum
  • ulceroglandular tularemia
  • plague
  • staph or strep cellulitis
  • HSV
  • cutaneous anthrax is painless
54
Q

Dx testing for cutaneous anthrax?

A
  • gram stain, PCR, or culture of vesicular fluid, exudate, or eschar
  • blood culture if systemic sxs present
  • bx for immunohistoschemistry, esp if person taking antimicrobials
55
Q

Presentation of inhalational (pulm) anthrax?

A
  • brief prodrome resembling viral like illness, characterized by myalgia, fatigue, fever, w/ or w/o resp sxs, followed by hypoxia, and dyspnea, often w/ radiographic evidence of mediastinal widening (due to hilar adenopathy)
  • meningitis: 50% of pts
56
Q

DDx for inhalational anthrax?

A
  • mycoplasmal pneumonia
  • legionnaires disease
  • Psittacosis
  • tularemia
  • Q fever
  • viral pneumonia
  • histoplasmosis
  • coccidioidomycosis
  • malignancy
57
Q

Presentation of GI anthrax?

A
  • abd distress, usually accompanied by bloody vomiting or diarrhea, followed by fever, and signs of septicemia
  • GI illness sometimes seen as oropharyngeal ulcerations w/ cervical adenopathy and fever
  • develops after ingestion of contaminated, poorly cooked meat
  • incubation: 1-7 days
  • case fatality: 25-60%
58
Q

DDx of GI anthrax?

A
  • acute appendicitis
  • ruptured viscus
  • diverticulitis
  • diseases that cause acute cervical lymphadenitis or acute gastritis
  • dysentery
59
Q

Anthrax tx protocol for cases assoc w/ bioterrorist events?

A
  • adults: cipro or doxy for 60 days

- kids: cipro or doxy (if older than 8 or weigh over 45 kg - diff dose than if under, also if under 8 - cipro)