Flashcards in GI Tract Infection Deck (36)
How is C. difficile transmitted?
What is the range of presentations of C. difficile?
1. Asymptomatic colonization
2. Mild-moderate diarrheal illness
3. Severe pseudomembranous colitis
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
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
All antibiotics can lead to C. diff colitis, but which 2 are the worst?
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
Clinical presentation of Toxic Megacolon
1. Abdominal pain/distension
2. Lactic acidosis
4. High WBC
5. May not have diarrhea
Tx of C. diff colitis
1. Mild-moderate disease --> Metronidazole
2. Severe disease --> Vancomycin PO
What are the 2 most common causes of Traveler's Diarrhea?
In general, a gradual onset or chronic low-grade diarrhea indicates what as a likely cause?
Giardia or Entamoeba histolytica
In general, bloody diarrhea with fever (dysentery) can be caused by which organisms?
In general, how does "food poisoning" present?
Brief episode of vomiting and diarrhea that resolves within 12 hours
Intestinal helminths are usually asymptomatic and not a cause of traveler's diarrhea, T or F?
When may it be necessary to identify the causative agent of diarrhea?
1. Severe symptoms
2. Persistent symptoms (beyond 72 hours)
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
Tx for diarrhea
2. Antibiotics for moderate-severe symptoms
3. Anti-motility agents
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
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
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
6. Prophylactic antibiotics: immunocompromised, IBS, or those at risk of dehydration
What is the leading cause of diarrhea in children?
The majority of diarrheal deaths are due to:
1. Unsafe water
2. Inadequate sanitation
3. Poor hygiene
When is rotavirus infection most common?
6-24 months - occurs with weaning. Baby is protected by IgA in breast milk
How might you Dx rotavirus infection?
What is the Tx for rotaviral diarrhea
1. Oral rehydration
3. Continued breast-feeding
How can rotaviral infection be prevented?
What is the major source of a bacterial liver abscess?
Describe the aspirate from a bacterial liver absess
Purulent, green/yellow, foul odor
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
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