Collagenous colitis is an inflammatory colonic disease with peak incidence in the 5th decade of life, affecting women more than men. Its clinical presentation involves watery diarrhea, usually in the absence of rectal bleeding. It is often classified under the umbrella entity microscopic colitis, along with a related condition, lymphocytic colitis
Symptoms The symptoms and signs may include: * Sudden onset of chronic watery diarrhoea * The diarrhoea may be relentless or may come and go in regular cycles * The diarrhoea does not contain blood or pus * Bowel incontinence * Abdominal pain and nausea * Abdominal bloating * Persistent fatigue * Weight loss.
The exact cause of collagenous colitis is unknown, but non-steroidals such as diclofenac are commonly implicated. The other group of agents most commonly associated with collagenous colitis are the selective serotonin reuptake inhibitors used in the treatment of depression.
On colonoscopy, the mucosa of the colon typically looks normal, but biopsies of affected tissue usually show deposition of collagen in the lamina propria, which is the area of connective tissue between colonic glands. Radiological tests, such as a barium enema are typically normal.
Treatment of collagenous colitis is often challenging, and many agents have been used therapeutically: * Bismuth agents, including Pepto-Bismol * 5-aminosalicylic acid * Budesonide * Immunosuppressants, including azathioprine * Corticosteroids