Diarrheal Diseases

Celiac sprue (Gluten-sensitive enteropathy):

• Flattening villi of proximal small bowel (jejunum)
• HLA DQ2\DQ8
• 50% have iron deficiency anemia
• Associated with: Dermatitis herpetiformis (papulovesicular lesions on extensor surface), DM type 1, other autoimmune, IgA deficiency
• Diagnosis:
  • Anti-endomysial antibody, Tissue tranglutaminase (tTG), Antigliadin antibody
  • Biopsy to exclude bowel wall lymphoma (minimum of 6 taken from 2^nd and 3^rd part of duodenum)
  • Gold standard: repeat endoscopy w\biopsy after gluten-free diet.
• Treatment: gluten-free diet, treat nutritional deficiencies

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Whipple disease:

• Usually in middle-aged men
• Caused by gram-positive bacillus (Tropheryma whippelii)
• Presentation: diarrhea, steatorrhea, abdominal pain, wt loss, migratory arthritis, fever, neurologic, cardiac and ophthalmologic manifestations
• Diagnosis: PAS-positive machrophages containing the bacillus in small bowel, PCR
• Treatment: trimethoprim-sulfamethoxazole for 1 year

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Bacterial overgrowth:

• Causes:
  • Small bowel stasis: due to anatomic abnormalities (post-surgical), or abnormal motility (DM)
  • Abnormal communication between small bowel and colon (Crohn fistula)
• Diagnosis:
  • Lactose: hydrogen breath test (early hydrogen peak),
  • ¹⁴C-D-Xylose breath test

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Irritable bowel syndrome (IBS):

• Sx aggravated by stress
• Dome III dx criteria:

 

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Inflammatory bowel disease (IBD):

 

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Download the PDF version: here

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References:

• USMLE step 1
• The Johns Hopkins Internal Medicine Board Review
• Step up to medicine
• Master the boards