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