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Flashcards in 03a: Infectious Deck (64)
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1
Q

Anaerobes are characterized by their ability to grow only in an atmosphere containing (X)% oxygen.

A

X = under 10

2
Q

Anaerobes are isolated in (X)% of all clinical infections.

A

X = 5-10

3
Q

Anaerobic bacteria are a component of the normal flora of:

A
  1. Skin
  2. Mouth
  3. GI tract
  4. F genital tract
4
Q

List Gram-negative anaerobes commonly identified in clinical practice.

A
  1. Fusobacterium
  2. Bacteriodes group (B. fragilis, Prevotella, etc)
  3. Veillonella
5
Q

List Gram-positive anaerobes commonly identified in clinical practice. Star the cocci.

A
  1. Peptostreptococcus*
  2. Clostridia
  3. Proprionobacterium
  4. Actinomyces
6
Q

T/F: Frequently, anaerobes are a component of polymicrobial (mixed) infections.

A

True

7
Q

T/F: Anaerobic infections commonly associated with gas in tissue and positive routine culture.

A

False in that it’s usually negative on routine culture

8
Q

Which type of bacteria associated with post-bite infections and (X) granules?

A

Anaerobes

X = sulfur

9
Q

T/F: most anaerobes will die once in contact with oxygen.

A

False - most are aerotolerant (not strict anaerobes)

10
Q

Obligate aerobes require (X)% oxygen to grow.

A

X = 15-21

11
Q

Which locations on normal person have highest anaerobes:aerobe ratio?

A
  1. Gingival surface
  2. Colon

Ratio is 1000:1

12
Q

Anaerobic infections generally arise from (X). List some exceptions.

A

X = endogenous flora

  1. Food poisoning from C. perfringens
  2. C. tetani infections
13
Q

Many anaerobic bacteria have (slow/fast) growth rates, making β-lactam antibiotics (more/less) effective.

A

Slow; less

14
Q

T/F: Anaerobes seldom involved in acute/chronic sinusitis and otitis media.

A

False - seldom in acute, but frequent in chronic

15
Q

T/F: Anaerobes seldom involved in meningitis.

A

True

16
Q

List some GI infections in which anaerobes seldom play a role.

A
  1. Acute cholecystitis
  2. Spontaneous peritonitis
  3. Cystitis
17
Q

T/F: Your diabetic patient has a foot ulcer that is now infected. The culprit is likely anaerobic.

A

True

18
Q

Between your patient with UTI/pyelonephritis and another with appendicitis, which is likely infected with anaerobe?

A

Appendicitis

19
Q

What are key things to keep in mind when collecting and processing anaerobic bacteria?

A
  1. Aspirate using needle and syringe
  2. Expulsion of air and sealing of syringe
  3. Prompt processing (under 2-3h)
20
Q

How could a swab be used to collect sample for anaerobe culture?

A

Place swab in Stuarts Transport Medium during 1-2h transport

21
Q

T/F: Room T is more conducive for anaerobe survival than refrigeration.

A

True

22
Q

While waiting for gram stain, which findings in bacterial specimen leads to suspicion of anaerobes?

A
  1. Foul odor
  2. Gas
  3. Necrotic tissue
  4. “Sulfur” granules
23
Q

Above diaphragm treatment for anaerobes typically involves:

A

Beta-lactam/beta-lactamase inhibitor combos

24
Q

Below diaphragm treatment for anaerobes typically involves:

A

Metronidazole

25
Q

Which antibiotics have proven active against both “arms” (above and below diaphragm) of anaerobic infections?

A

New beta-lactams (ex: piperacillin/tozobactam) and tigecycline

26
Q

Most common reasons for failure of therapy in anaerobic infections:

A
  1. Undrained pus

2. Insufficient duration of antibiotics

27
Q

Gut anaerobes (commensals) are important in (X) metabolism.

A

X = CHO, vitamin K, bile acids, and some drugs

28
Q

What are the most common anaerobes involved in infectious states (immuno-competent host).

A
  1. Peptostreptococcus
  2. Prevotella
  3. Bacteriodes
  4. Fusobacterium
29
Q

(X) species are the most

commonly isolated microorganisms in intra-abdominal infections.

A

X = E. coli (aerobic) and Bacteriodes (anaerobic)

30
Q

Two major causes of visceral pain in GI.

A
  1. Distension (stool, fluid, gas)

2. Obstruction

31
Q

T/F: GI viscera are relatively insensible to most stimuli, so pain is fairly indicative of tissue damage.

A

False - despite being relatively insensible, pain in GI viscera will occur even in absence of tissue damage

32
Q

(X) is a GI disorder characterized by chronic abdominal pain and altered bowel habits in the absence of any organic cause.

A

X = IBS (irritable bowel syndrome)

33
Q

Patients with IBS have changes in (X), which is what causes their Sx.

A

X = neurologic processing of bowel sensation and motor function

34
Q

List the three characteristics of IBS pathophysiology.

A
  1. Altered GI motility (increased reactivity to meals, stress, distention, CCK)
  2. Altered visceral sensation (hypersensitivity)
  3. CNS-Enteric NS dysregulation
35
Q

IBS patients have an (absent/exaggerated) gastrocolic response, so (X) immediately causes (Y).

A

Exaggerated;
X = gastric distention after meals
Y = fecal urgency and diarrhea

36
Q

(X) is the primary NT of the GI tract, released from (Y).

A
X = serotonin (5-HT)
Y = ECC (enterochromaffin cells)

95% of serotonin in body found in GI tract!

37
Q

Serotonin role in GI tract.

A

Initiates peristaltic, secretory, vasodilatory, vagal, and nociceptive reflexes

38
Q

T/F: Serotonin regulates nausea/vomiting in CNS.

A

True

39
Q

Which NT receptors in GI tract are implicated in pathophysiology of IBS? Therapeutic agents target these receptors for (activation/inactivation).

A

Serotonin (5-HT3 and 5-HT4)

Inactivation (antagonizing)

40
Q

Rome IV Criteria is for diagnosing (X).

A

X = IBS

41
Q

Rome IV Critera: 3 months of (X) at least (1/3/5) days per week and associated with 2 or more of following:

A

X = abdominal pain (recurrent)
1 day/week

  1. Defacation
  2. Change in stool frequency
  3. Change in stool appearance/form
42
Q

IBS Subtypes:

A
  1. IBS with constipation
  2. IBS with diarrhea
  3. Mixed IBS
  4. Unsubtyped IBS (doesn’t meet criteria for other subtypes)
43
Q

Patient meets criteria for IBS diagnosis and reports that over 50% of her stools are watery and she never has hard/lumpy stools. Which subtype would you place her in?

A

IBS with diarrhea (over 25% are loose/watery and under 25% are hard)

44
Q

Patient meets criteria for IBS diagnosis and reports that he never has normal stools - they’re always either hard/lumpy or watery. He reports the ratio is about 1:1. Which subtype would you place him in?

A

Mixed IBS (over 25% are loose and over 25% are hard)

45
Q

Most recent estimates yield IBS rates around (X)% with F:M ratio of (Y).

A
X = 10
Y = 3:1
46
Q

First IBS presentation typically occurs around ages (X) and prevalence decrease after age (Y).

A
X = 30-50
Y = 60
47
Q

T/F: A diagnosis of IBS is life-long.

A

True - chronic disease, though symptoms wax and wane

48
Q

Diagnosis of IBS made when which 3 criteria are met?

A
  1. Rome criteria fulfilled
  2. No “alarm symptoms”
  3. Negative screening studies
49
Q

Patient may meet Rome criteria for IBS, but presence of “alarm symptom” such as (X) would prompt additional workup.

A

X = weight loss, blood in stool, nocturnal Sx, abnormal PE, FHx of colon cancer

50
Q

Patient presents with IBS-like symptoms, but he has cousin with Crohn’s. Which screening test(s) could you do to rule out IBD?

A

ESR and CRP

51
Q

Patient presents with IBS-like symptoms. You run a TTG serology to screen/exclude (X) etiology.

A

X = Celiac

52
Q

T/F: Workup for diagnosing IBS includes screening for infectious pathogens.

A

True - stool for ova/parasites

53
Q

List the three symptom groups of IBS.

A
  1. Abdominal pain/bloating
  2. Diarrhea
  3. Constipation
54
Q

Abdominal pain/bloating Rx for IBS includes which agents?

A
  1. Anticholinergic

2. 5-HT3 R antagonism (SSRIs commonly used instead)

55
Q

T/F: Opioids are commonly prescribed to relieve abdominal pain/bloating in IBS.

A

False - prescribed for diarrheal symptoms

56
Q

List two opioids used in IBS when (X) is the predominant symptom.

A

X = diarrhea

  1. Loperamide
  2. Diphenoxylate
57
Q

Aside from opioids, (X) drug has been shown to improve (Y) symptom in IBS. What’s the likely mechanism?

A
X = rifaximin (antibiotic)
Y = diarrhea

Likely alters gut flora composition

58
Q

First line therapy for severe IBS constipation is (X), which is effective in (minority/majority) of cases.

A

X = fiber supplementation

Minority

59
Q

What could you try next if fiber supplementation, for treating (X) symptom of IBS, fails? What’s the mechanism behind this?

A

X = constipation

Surfactants (docusate Na) - impair small intestinal water absorption

60
Q

Your patient with IBS-constipation is relieved to find that OTC senna (a stimulant laxative) has significantly helped her symptoms. What advice do you give her?

A

Stimulant laxatives not recommended for chronic use - you can prescribe osmotic laxatives and other effective therapies

61
Q

Most effective therapies for severe IBD constipation:

A
  1. Osmotic laxatives (Mg salts, lactulose, sorbitol)
  2. Miralax (polyethylene glycol)
  3. Bowel retraining
62
Q

Prostaglandin analogues are being used to treat (X) symptom of IBS.

A

X = constipation

63
Q

A new drug, (X), is used for (diarrhea/constipation) IBD and mimics which bacterial toxin?

A

X = linaclotide
Constipation

ETEC (diarrhea-induction via cGMP production and increased fluid/electrolyte secretion)

64
Q

IBS patient with (X) symptoms is candidate for tricyclic antidepressant therapy.

A

X = diarrhea, nausea, abdominal pain