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Microscopic Colitis: Causes and Treatment


By Steven Desautels, MD

Microscopic colitis is a chronic inflammatory disease of the colon that is characterized by watery, non-bloody diarrhea. Microscopic colitis should be suspected in patients with chronic diarrhea without a clear cause. There is a female predominance and the median age at diagnosis is approximately 65 years. Colonoscopic investigation reveals an endoscopically normal-appearing colon; however, biopsy evaluation demonstrates either a collagenous or lymphocytic colitis.

Collagenous colitis is characterized by a sub epithelial collagen band > 10 mm in thickness with lymphocytic colitis demonstrating an intraepithelial lymphocytic infiltrate (>20 per high power field).

Microscopic Colitis Causes

The cause of microscopic colitis is unknown, but it is likely to be related to a multitude of factors, including mucosal immune responses to luminal factors and various medications (e.g. non-steroidal anti-inflammatory drugs, Proton pump inhibitors, Sertraline and Clozapine).

Treating Microscopic Colitis

Antidiarrheal medications may be used in patients with mild diarrhea, but for patients experiencing greater than three stools per day or greater than one water stool daily, budesonide is usually required. The dosing of budesonide is associated based on the clinical response, and usually only requires short-term treatment courses. Patients are advised to avoid non-steroidal anti-inflammatory medications, and, if possible, discontinue medications associated with microscopic colitis. In very rare, refractory cases, anti-tumor necrosis factor (TNF) agents may be necessary.

The gastroenterology specialists at Granite Peaks Gastroenterology can evaluate patients experiencing chronic diarrhea, determine the cause of the symptoms and treat appropriately based on test results.