An unexpected CT finding in a patient with abdominal pain.

A fit and well 16-year-old girl presented to the emergency department with signs and symptoms suggestive of appendicitis. A transabdominal ultrasound scan revealed a normal appendix but there was significant free fluid in the pelvis. Consequently, a CT scan of her abdomen was performed which showed mucosal oedema and inflammation involving virtually the entire length of her large bowel (the 'accordion sign'). Clostridium difficile colitis was thus suspected; however, the toxin was not detected in her stool. The patient was treated conservatively with intravenous fluids and antibiotics and had an uneventful recovery. She was subsequently discharged home 3 days later with a full recovery. In this case, the radiological appearance of the accordion sign which is traditionally known to be pathognomonic of pseudomembranous colitis, reveals that it may also be indicative of severe colonic luminal inflammation.