GI Tract Infection

Question 1

What is the range of presentations of C. difficile?

Answer 1

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

Question 2

Outline C. difficile pathogenesis

Answer 2

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

Question 3

What type of toxins does C. difficile produce?

Answer 3

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

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

Question 4

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

Answer 4

1. Clindamycin

2. Fluoroquinolones

Question 5

Clinical presentation of C. diff colitis

Answer 5

Symptoms begin during or within 2 weeks after antibiotics

1. Watery diarrhea > 3 stools/day
2. Elevated WBC
3. Low grade fever

Question 6

Clinical presentation of Toxic Megacolon

Answer 6

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

Question 7

Tx of C. diff colitis

Answer 7

1. Mild-moderate disease –> Metronidazole

2. Severe disease –> Vancomycin PO

Question 8

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

Answer 8

1. ETEC

2. EAEC

Question 9

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

Answer 9

Giardia or Entamoeba histolytica

Question 10

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

Answer 10

1. Shigella
2. Campylobacter
3. Salmonella

Question 11

In general, how does “food poisoning” present?

Answer 11

Brief episode of vomiting and diarrhea that resolves within 12 hours

Question 12

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

Answer 12

TRUE

Question 13

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

Answer 13

1. Severe symptoms

2. Persistent symptoms (beyond 72 hours)

Question 14

List the appropriate investigations for diarrhea

Answer 14

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

Question 15

Tx for diarrhea

Answer 15

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

Question 16

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

Answer 16

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

Question 17

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

Answer 17

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

Question 18

Prevention of Traveler’s diarrhea may include:

Answer 18

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

Question 19

What is the leading cause of diarrhea in children?

Answer 19

Rotavirus

Question 20

The majority of diarrheal deaths are due to:

Answer 20

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

Question 21

When is rotavirus infection most common?

Answer 21

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

Question 22

How might you Dx rotavirus infection?

Answer 22

1. ELISA

2. PCR

Question 23

What is the Tx for rotaviral diarrhea

Answer 23

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

Question 24

How can rotaviral infection be prevented?

Answer 24

ROTARIX vaccine

Question 25

What is the major source of a bacterial liver abscess?

Answer 25

Biliary (60%)

Question 26

Describe the aspirate from a bacterial liver absess

Answer 26

Purulent, green/yellow, foul odor

Question 27

Outline the Tx of a bacterial liver abscess

Answer 27

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

Question 28

List some adaptations that H. pylori has for its host

Answer 28

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

Question 29

What is the most common cause of gastritis?

Answer 29

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

Question 30

Who should be tested for H. pylori?

Answer 30

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

Question 31

What testing is available for H. pylori?

Answer 31

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

Question 32

Tx for H. pylori

Answer 32

1. HP-Pac: Lansoprazole + Clarithromycin + Amoxicillin

Question 33

Tx for oropharyngeal candidiasis

Answer 33

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

Question 34

Tx for esophageal candidiasis

Answer 34

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

Question 35

Liver abscess is a serious condition which requires:

Answer 35

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

Question 36

How is C. difficile transmitted?

Answer 36

Fecal-oral route