Microscopic colitis is an inflammatory condition that affects the large intestine (colon) and causes persistent watery diarrhea. Microscopic colitis must be diagnosed with a microscope. There are two forms of microscopic colitis. Lymphocytic colitis results from abundant white cells in the superficial colon lining causing inflammation. Collagenous colitis occurs when protein (collagen) material accumulates in the colon lining causing symptoms.
Microscopic colitis causes profuse watery diarrhea 4-8 times per day. Fecal incontinence, abdominal pain, and weight loss are less common complaints. Diarrhea can resolve spontaneously without medical intervention. Symptoms may occur regularly then remit or go away for long periods of time (spontaneous remission).
The cause of microscopic colitis is not certain. Many believe that medications can contribute and may cause inflammation of the colon lining. Medications such as non-steroidal anti-inflammatory agents (NSAIDS) or aspirin and ibuprofen can contribute. Other medications reported causing lymphocytic colitis include proton pump inhibitors for such as omeprazole and lansoprazole, depression medications such as sertraline (Zoloft), and carbamazepine Bacterial or viral toxins have been implicated as a potential cause. Autoimmune disease such as celiac disease occurs more commonly in lymphocytic colitis. Middle-aged women (50-70 years old) are more commonly affected than men.
Diagnosis involves testing to exclude other causes of diarrhea. Stool studies are recommended. A colonoscopy with biopsies is diagnostic. Treatment includes stopping offending medications such as aspirin or ibuprofen. Anti-diarrheal medications are used to control diarrhea. Anti-inflammatory medications such as melamine or gut-specific steroid medications are given and very helpful.