Which are the symptoms?
The main symptom of microscopic colitis is chronic watery diarrhoea without discharge of blood, usually developing unnoticed, acute in a minority of cases. Other symptoms include urgency on defecation, urinary incontinence, nocturnal secretions, and abdominal pain, with often reduced quality of life. Extraintestinal manifestations, including arthritis or uveitis, may occur rarely. Laboratory tests are usually non-specific: mild anaemia, increased inflammatory signs and the presence of autoantibodies are found in almost half of patients.
- Chronic watery diarrhoea with nocturnal discharge
- Abdominal pain
How is it diagnosed?
The first diagnostic task is to exclude the most common causes of chronic diarrhoea. First-line investigations include a coeliac test, co-culture and parasitological tests, as well as blood tests, electrolytes and serum albumin. Colonoscopy with biopsy of the right and left colon is the definitive diagnostic test. The two forms of the disease can be distinguished on the basis of histological examination. In cases where histological abnormalities do not meet the diagnostic criteria of one of the subforms of microscopic colitis, the term "otherwise unspecified colitis" is used.
How is it treated?
For the clinical treatment of mild diarrhoea, common anti-diarrhoeal drugs such as loperamide or cholestyramine are used, especially in the evening to reduce nocturnal secretions. These drugs are often used in combination with budesonide, a topical corticosteroid drug, with very good results. 80% of cases relapse when therapy is discontinued. Systemic corticosteroids are indicated for patients whom cannot use budesonide. If there is no clinical improvement, immunosuppressive drugs such as anti-TNF monoclonal antibodies can be used, although rarely. If there is no response to drug therapy, the last resort is surgery, including ileostomy, sigmoidostomy or colectomy.