History A 35-year-old woman has a year-long history of intermittent diarrhoea which has never been bad enough for her to seek medical help in the past. However, she has become much worse over 1 week with episodes of bloody diarrhoea 10 times a day
What is your interpretation of these results? What is the likely diagnosis and what should be the management? Answer: Bloody diarrhoea 10 times a day suggests a serious active colitis. In the absence of any recent foreign travel it is most likely that this is an acute episode of ulcerative colitis on top of chronic involvement. The dilated colon suggests a diagnosis of toxic megacolon which can rupture with potentially fatal consequences. Investigations such as sigmoidoscopy and colonoscopy may be dangerous in this acute situation, and should be deferred until there has been reasonable improvement. The blood results show a microcytic anaemia suggesting chronic blood loss, low potassium from diarrhoea (explaining in part her weakness) and raised urea, but a normal creatinine, from loss of water and electrolytes. If the history was just the acute symptoms, then infective causes of diarrhoea would be higher in the differential diagnosis. Nevertheless, stool should be examined for ova, parasites and culture. Inflammatory bowel disorders have a familial incidence but the patient’s aunt has an unknown condition and the relationship is not close enough to be helpful in diagnosis. Smoking is associated with Crohn’s disease but ulcerative colitis is more common in non-smokers. She should be treated immediately with corticosteroids and intravenous fluid replacement, including potassium. If the colon is increasing in size or is initially larger than 5.5 cm then a