Clinical features

The main symptoms are frequent, and often, urgent passage of bloody diarrhoea, pus and mucus accompanied by abdominal pain. These symptoms occur in exacerbations lasting several days or weeks at a time. The severity of the symptoms varies between individuals and reflects the amount of the bowel that is affected. Fever, poor appetite, weight loss and feelings of lassitude accompany episodes. In severe attacks diarrhoea with bleeding can occur many times throughout the day and at night.

There are often few symptoms on examination apart from some mild abdominal tenderness. Some people may be pale due to anaemia. Diagnosis is confirmed by direct examination of the bowel via sigmoidoscopy and/or colonoscopy, when a small sample of the bowel mucosa can be removed and examined under the microscope (biopsy).

In a minority of cases hospital admission occurs because of severe illness and/or development of complications. Complications include dehydration, collapse, severe bleeding, swelling and perforation of the bowel (toxic mega colon).

The development of cancer of the colon is a late complication.

Amended April 2008