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SynopsisMicroscopic colitis is a subtype of inflammatory bowel disease that is characterized clinically by a chronic, watery diarrhea with normal endoscopic appearance but histologic evidence of chronic inflammation. The etiology is unknown. Microscopic colitis is subdivided into 2 primary types: collagenous colitis and lymphocytic colitis, determined by histologic appearance.
Microscopic colitis is more common in adults older than 60 years and has an incidence of approximately 8.6 cases per 100 000 person-years. Female patients are more likely to have collagenous colitis, but there is no clear gender predilection in lymphocytic colitis.
The most common symptom is a chronic, watery diarrhea. Hematochezia, melena, and bright red blood per rectum (BRBPR) are uncommon. Some patients will experience weight loss and malaise. Abdominal pain, cramps, bloating, nausea, and fecal incontinence have also been reported. Undiagnosed and untreated, symptoms from microscopic colitis are often continual, although they may not progressively worsen.
Patients with autoimmune diseases such as type 1 diabetes mellitus, celiac disease, and autoimmune thyroiditis are at increased risk of developing microscopic colitis. Additionally, smoking and many medications are associated with microscopic colitis.
K52.831 – Collagenous colitis
K52.832 – Lymphocytic colitis
K52.839 – Microscopic colitis, unspecified
235753003 – Microscopic colitis
Differential Diagnosis & Pitfalls
- Celiac disease
- Infectious gastroenteritis
- Inflammatory bowel disease (see Crohn disease, ulcerative colitis)
- Bile acid diarrhea
- Carbohydrate malabsorption (ie, lactose intolerance, fructose intolerance, sorbitol intolerance)
- Irritable bowel syndrome, diarrheal-type
- Small intestinal bacterial overgrowth
- Pancreatic insufficiency
- Laxative abuse
- Carcinoid syndrome
Drug Reaction DataBelow is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.