In microscopic colitis, the colon appears normal with endoscopy, but the inflammation is apparent in the biopsy specimens collected in connection with it. Microscopic colitis can be further specified as collagenous colitis or lymphocytic colitis. The cause of the disease is unknown, but hereditary factors are considered to affect the risk of developing the disorder. Previous infections, anti-inflammatory painkillers, some antidepressants and proton pump inhibitors may also be triggering factors. In addition, other autoimmune diseases, such as type I diabetes, thyroid diseases and celiac disease, increase the risk of developing microscopic colitis.
Microscopic colitis symptoms include prolonged watery diarrhoea and abdominal pain. Chronic diarrhoea refers to situations where bowel movements occur several times a day and produce loose stools for more than three weeks. In microscopic colitis, haematochezia is rarely present. Blood may, of course, be observed due to haemorrhoids or if diarrhoea has irritated the anus. Particularly severe diarrhoea may also cause weight loss. Tenesmus and bowel incontinence may be involved for some patients. Symptoms may also occur at night, which usually differentiates microscopic colitis from irritable bowel syndrome (IBS). Symptoms are typically chronic, but sometimes symptoms may come about suddenly. It is common for the disease to involve fluctuations between acute and calmer periods. In some cases, the condition may calm down by itself, in which case medication is not required.
Diagnosis requires colonoscopy and the collection of several biopsy specimens in which the inflammation is microscopically visible. When the disease is diagnosed, it is worth reviewing any current medication to assess whether any administered anti-inflammatory painkillers or proton pump inhibitors could be replaced with alternative pharmaceutical products because they may trigger microscopic colitis. Symptoms often settle once the medication is discontinued. Primary pharmaceutical treatment includes antidiarrheals, and their occasional administration benefits many patients. Some patients benefit from fibre supplements. In some cases, various medications and cortisone courses may be used. Extremely rarely, a J-pouch surgery may be carried out.