GI Tract Infection Flashcards Preview

Infectious Disease and Medical Microbiology > GI Tract Infection > Flashcards

Flashcards in GI Tract Infection Deck (36)
0

How is C. difficile transmitted?

Fecal-oral route

1

What is the range of presentations of C. difficile?

1. Asymptomatic colonization
2. Mild-moderate diarrheal illness
3. Severe pseudomembranous colitis

2

Outline C. difficile pathogenesis

1. Transmission and colonization
2. Antibiotic use
3. Disruption of normal intestinal flora
4. Release of Toxin A and Toxin B
5. Mucosal injury and inflammation
6. C. diff colitis

3

What type of toxins does C. difficile produce?

1. Toxin A = enterotoxin
2. Toxin B = cytotoxin

Both cause inflammation, neutrophil activation/chemotaxis, mucosal injury, and intestinal secretion

4

All antibiotics can lead to C. diff colitis, but which 2 are the worst?

1. Clindamycin
2. Fluoroquinolones

5

Clinical presentation of C. diff colitis

Symptoms begin during or within 2 weeks after antibiotics
1. Watery diarrhea > 3 stools/day
2. Elevated WBC
3. Low grade fever

6

Clinical presentation of Toxic Megacolon

1. Abdominal pain/distension
2. Lactic acidosis
3. Hypovolemia
4. High WBC
5. May not have diarrhea

7

Tx of C. diff colitis

1. Mild-moderate disease --> Metronidazole
2. Severe disease --> Vancomycin PO

8

What are the 2 most common causes of Traveler's Diarrhea?

1. ETEC
2. EAEC

9

In general, a gradual onset or chronic low-grade diarrhea indicates what as a likely cause?

Giardia or Entamoeba histolytica

10

In general, bloody diarrhea with fever (dysentery) can be caused by which organisms?

1. Shigella
2. Campylobacter
3. Salmonella

11

In general, how does "food poisoning" present?

Brief episode of vomiting and diarrhea that resolves within 12 hours

12

Intestinal helminths are usually asymptomatic and not a cause of traveler's diarrhea, T or F?

TRUE

13

When may it be necessary to identify the causative agent of diarrhea?

1. Severe symptoms
2. Persistent symptoms (beyond 72 hours)

14

List the appropriate investigations for diarrhea

1. Stool culture - CAN identify Shigella, Salmonella, and Campylobacter. Do for: immunocompromised, dysentery, outbreaks
2. Stool microscopy (O/P) - Do for symptoms lasting > 10 days
3. EIA for Giardia and Cryptosporidium

15

Tx for diarrhea

1. FLUIDS
2. Antibiotics for moderate-severe symptoms
3. Anti-motility agents

16

Antibiotics may be given as a single dose or for 1 day in the Tx of diarrhea - name 2 agents used for this.

1. Fluoroquinolone - shortens duration of diarrhea from 3 to 1 day
2. Azithromycin - best for kids and Campylobacter

17

What are 3 guidelines for the use of anti-motility agents in the Tx of diarrhea?

1. DO NOT use in dysentery
2. Always use with an antibiotic
3. Don't forget to hydrate

18

Prevention of Traveler's diarrhea may include:

1. Boil it, peel it, cook it
2. Bottled water
3. Avoid salad and peeled fruits/vegetable
4. Bismuth subsalicylate
5. Probiotics
6. Prophylactic antibiotics: immunocompromised, IBS, or those at risk of dehydration

19

What is the leading cause of diarrhea in children?

Rotavirus

20

The majority of diarrheal deaths are due to:

1. Unsafe water
2. Inadequate sanitation
3. Poor hygiene

21

When is rotavirus infection most common?

6-24 months - occurs with weaning. Baby is protected by IgA in breast milk

22

How might you Dx rotavirus infection?

1. ELISA
2. PCR

23

What is the Tx for rotaviral diarrhea

1. Oral rehydration
2. Zinc
3. Continued breast-feeding

24

How can rotaviral infection be prevented?

ROTARIX vaccine

25

What is the major source of a bacterial liver abscess?

Biliary (60%)

26

Describe the aspirate from a bacterial liver absess

Purulent, green/yellow, foul odor

27

Outline the Tx of a bacterial liver abscess

1. Empiric coverage for enteric GNRs, Enterococcus and anaerobes for 4-6 weeks.
2. Percutaneous drainage essential

28

List some adaptations that H. pylori has for its host

1. Urease - hydrolyzes urea to ammonium to neutralize stomach acid
2. Spiral shape, flagella, and mucolytic enzymes allow it to swim thru mucus to epithelium
3. Adhesions bind to epithelial receptors

29

What is the most common cause of gastritis?

H. pylori - also gives an increased risk of gastric cancer

30

Who should be tested for H. pylori?

1. Pt's with gastric cancer
2. Active peptic ulcer disease
3. Hx of peptic ulcer disease
4. Symptoms of dyspepsia

31

What testing is available for H. pylori?

1. Urease breath test
2. Serology
3. Stool Ag
4. Endoscopy + biopsy

32

Tx for H. pylori

1. HP-Pac: Lansoprazole + Clarithromycin + Amoxicillin

33

Tx for oropharyngeal candidiasis

1. Nystatin
2. Clotrimazole troches
3. Fluconazole
4. Anti-retroviral therapy (HIV)

34

Tx for esophageal candidiasis

1. ALWAYS systemic anti-fungals
2. Fluconazole OR
3. Echinocandins OR
4. Amphotericin B

35

Liver abscess is a serious condition which requires:

1. Prompt hospitalization
2. CT scan
3. Empiric antibiotic therapy (enteric Gram -ve, enterococcus, and anaerobes)