Microscopic Colitis

In patients that complain of long-standing, watery diarrhea, consider Microscopic Colitis.


Microscopic Colitis

  • 10-15% of patients with aforementioned symptoms.
  • Typical profile:  Old people with unrevealing gross colonoscopy exam.
  • MUST biopsy, since the differential includes Celiac and IBS.
  • Subtypes
    • Lymphocytic and Collagenous colitis
  • Pathophysiology
    • Unknown, may be due to PPIs or NSAIDs
    • Important!  Test for other concomitant diseases, as MC can be found with:
      • Autoimmune:  Diabetes (A1C) and/or Psoriasis (look for lesions)
      • Malabsorption:  Celiac Sprue
  • Diagnosis
    • Histology of tissue sample:  intraepithelial lymphocytosis ( > 20 lymphocytes per 100 epithelial cells)
    • Collagenous colitis:  beefier subepithelial collagen band.
  • Treatment
    • If medication temporally associated, discontinue offending agent.
    • Antidiarrheal – diphenoxylate or loperamide
    • Bismuth subsalicylate in moderate disease
    • Budesonide in severe/refractory cases.
      • Do not abruptly discontinue due to relapse.


  • ACP MKSAP 17:  Gastroenterology and Hepatology, pgs. 41-42
  • Image source:  https://en.wikipedia.org/wiki/Microscopic_colitis

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