Pseudomembranous collagenous colitis: an unusual cause of chronic diarrhoea.

An 81-year-old woman presented with a history of severe chronic diarrhoea resulting in an admission with syncope and electrolyte abnormalities. Imaging studies of the bowel were normal. However, biopsies taken during colonoscopy enabled a diagnosis to be made and effective treatment to be initiated. This case report details the presentation, diagnosis and management of a rare injury pattern affecting the bowel: pseudomembranous collagenous colitis.