• Approach to Diarrhea
  • Acute vs. Chronic
    • Acute is more likely to be infectious and self-limited
  • Chronic Diarrhea
    • inflammatory - lower volume, bloody with mucous, relieved by defecation, tenesmous
    • Fatty - lower volume, floats, smells really bad
    • Osmotic - medium volume, watery, improves with fasting
    • Secretory - high volume, watery, no change with fasting
  • History gives you the diagnosis
    • Ask patients about frequency to assess volume of diarrhea
    • Patients usually define diarrhea as loose stool so treating with fiber can help bulk up diarrhea
    • Also ask about associated systemic symptoms such as fevers, rash, joint pain and eye symptoms
  
  

  Posted 10/17/16 10:03:58 AM by Ying Liu

• Workup
  • Serological Workup
    • Basic labs to look at bicarb/electrolytes and potential anemia as well as albumin
    • Anti-transglutaminase antibodies (Anti-TTG, IgA) to rule out Celiac's. Send Quantitative Immunoglobulins and Anti-Gliadin antibodies to rule out IgA deficiency (can lead to false negative on TTG testing) and get definitive answer
    • ESR/CRP to assess for IBD
  • Stool Tests
    • C. Diff is low yield and can lead to false positives
    • Fecal fat for fatty diarrhea
    • Fecal Leukocytes for IBD
    • Stool Osmolar to differentiate between secretory and osmotic diarrhea
      • Gap 290 − 2 * (stool Na + stool K)
      • High osmotic gap (>100 mosm/kg) suggest Osmotic diarrhea (Celiac sprue, chronic pancreatitis, lactase deficiency, laxative use/abuse, and Whipple's disease)
        • Molecules such as unabsorbed carbohydrates are more significant contributors to stool osmolality leading to high osmotic gap
      • Low osmotic gap (<50 mosm/kg) suggests secretory diarrhea (Toxin mediated such as cholera and ETEC, secretagogues such as vasoactive intestinal peptide from VIPomas, gastrinomas, medullary thyroid carcinoma which produces excess calcitonin, and villous adenoma)
        •  Secreted sodium and potassium ions make up a greater percentage of the stool osmolality in secretory diarrhea so osmotic gap is low
  • Invasive Testing
    • Endoscopy is indicated to definitively rule out Celiac's and help with management
    • Colonoscopy is indicated to evaluate for IBD and malignancy. Biopsies are needed to rule out microscopic colitis
  
  

  Posted 10/17/16 10:13:28 AM by Ying Liu

• Lactose Intolerance
  • Can be caused by lactase deficiency
  • Lactase becomes deficient as we age
  • Lactase is present in villi of intestines and can be destroyed during any illness that affects intestinal lining, so concomitant diarrheal disorder and exacerbate or reveal and underlying lactose intolerance
  
  

  Posted 10/17/16 10:14:50 AM by Ying Liu

• Microscopic Colitis
  • Chronic, inflammatory disease of the colon that's characterized by watery diarrhea
  • Occurs in middle-age with female preponderance (3-5 cases per 100,000 people per year)
  • Two types:
    • Lymphocytic: intraepithelial lymphocytic infiltrate
    • Collagenous: colonic sub-epithelial collagen band
  • Triggers include NSAIDs and PPIs
  • Treat with steroids (budesonide) and cessation of NSAIDs and PPI's
  
  

  Posted 10/17/16 10:16:30 AM by Ying Liu

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Created by Christopher Kelly

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