A 60 year old woman with no medical history of note except pan-proctocolectomy and ileostomy for Crohn's disease was admitted with a week's history of dizziness, lethargy, anorexia, vomiting, and confusion. She was found to have increased stoma volumes for a few days before admission and was on no particular medication. On examination, she was afebrile, dehydrated, and slightly disorientated with a pulse of 110 beats/min and blood pressure 100/60 mm Hg (no postural drop). Her abdomen was soft and stoma site intact but there was diffuse abdominal tenderness with intact peristaltic sounds. The rest of the general and systemic examination was unremarkable.

Investigations revealed a normal full blood count, C reactive protein, plasma glucose, liver function, arterial blood gas, and lipid profile. Her serum sodium concentration was low at 107 mmol/l, potassium 6.0 mmol/l, urea 8.5 mmol/l, and creatinine 80 mmol/l. Electrocardiography and radiography of the abdomen and chest were normal and blood culture was negative. An ultrasound scan of the abdomen was unremarkable. She was given intravenous fluids and treated symptomatically with antiemetics.