GI Tract Infection Flashcards
What is the range of presentations of C. difficile?
- Asymptomatic colonization
- Mild-moderate diarrheal illness
- Severe pseudomembranous colitis
Outline C. difficile pathogenesis
- Transmission and colonization
- Antibiotic use
- Disruption of normal intestinal flora
- Release of Toxin A and Toxin B
- Mucosal injury and inflammation
- C. diff colitis
What type of toxins does C. difficile produce?
- Toxin A = enterotoxin
- 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?
- Clindamycin
2. Fluoroquinolones
Clinical presentation of C. diff colitis
Symptoms begin during or within 2 weeks after antibiotics
- Watery diarrhea > 3 stools/day
- Elevated WBC
- Low grade fever
Clinical presentation of Toxic Megacolon
- Abdominal pain/distension
- Lactic acidosis
- Hypovolemia
- High WBC
- May not have diarrhea
Tx of C. diff colitis
- Mild-moderate disease –> Metronidazole
2. Severe disease –> Vancomycin PO
What are the 2 most common causes of Traveler’s Diarrhea?
- ETEC
2. EAEC
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?
- Shigella
- Campylobacter
- Salmonella
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?
TRUE
When may it be necessary to identify the causative agent of diarrhea?
- Severe symptoms
2. Persistent symptoms (beyond 72 hours)
List the appropriate investigations for diarrhea
- Stool culture - CAN identify Shigella, Salmonella, and Campylobacter. Do for: immunocompromised, dysentery, outbreaks
- Stool microscopy (O/P) - Do for symptoms lasting > 10 days
- EIA for Giardia and Cryptosporidium
Tx for diarrhea
- FLUIDS
- Antibiotics for moderate-severe symptoms
- 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.
- Fluoroquinolone - shortens duration of diarrhea from 3 to 1 day
- Azithromycin - best for kids and Campylobacter
What are 3 guidelines for the use of anti-motility agents in the Tx of diarrhea?
- DO NOT use in dysentery
- Always use with an antibiotic
- Don’t forget to hydrate
Prevention of Traveler’s diarrhea may include:
- Boil it, peel it, cook it
- Bottled water
- Avoid salad and peeled fruits/vegetable
- Bismuth subsalicylate
- Probiotics
- Prophylactic antibiotics: immunocompromised, IBS, or those at risk of dehydration
What is the leading cause of diarrhea in children?
Rotavirus
The majority of diarrheal deaths are due to:
- Unsafe water
- Inadequate sanitation
- 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?
- ELISA
2. PCR
What is the Tx for rotaviral diarrhea
- Oral rehydration
- Zinc
- Continued breast-feeding
How can rotaviral infection be prevented?
ROTARIX vaccine
What is the major source of a bacterial liver abscess?
Biliary (60%)
Describe the aspirate from a bacterial liver absess
Purulent, green/yellow, foul odor
Outline the Tx of a bacterial liver abscess
- Empiric coverage for enteric GNRs, Enterococcus and anaerobes for 4-6 weeks.
- Percutaneous drainage essential
List some adaptations that H. pylori has for its host
- Urease - hydrolyzes urea to ammonium to neutralize stomach acid
- Spiral shape, flagella, and mucolytic enzymes allow it to swim thru mucus to epithelium
- Adhesions bind to epithelial receptors
What is the most common cause of gastritis?
H. pylori - also gives an increased risk of gastric cancer
Who should be tested for H. pylori?
- Pt’s with gastric cancer
- Active peptic ulcer disease
- Hx of peptic ulcer disease
- Symptoms of dyspepsia
What testing is available for H. pylori?
- Urease breath test
- Serology
- Stool Ag
- Endoscopy + biopsy
Tx for H. pylori
- HP-Pac: Lansoprazole + Clarithromycin + Amoxicillin
Tx for oropharyngeal candidiasis
- Nystatin
- Clotrimazole troches
- Fluconazole
- Anti-retroviral therapy (HIV)
Tx for esophageal candidiasis
- ALWAYS systemic anti-fungals
- Fluconazole OR
- Echinocandins OR
- Amphotericin B
Liver abscess is a serious condition which requires:
- Prompt hospitalization
- CT scan
- Empiric antibiotic therapy (enteric Gram -ve, enterococcus, and anaerobes)
How is C. difficile transmitted?
Fecal-oral route
