Severe convulsant hypomagnesaemia and short bowel syndrome

Hypomagnesaemia as a primary cause of a generalized seizure is uncommon. A 60-year-old woman with Crohn's disease who had had recent small bowel surge ry and a total colectomy 10 years previously, was admitted complaining of s evere nausea, vomiting, fatigue and thirst. Despite oral magnesium ther npy she had a generalized seizure due to severe hypomagnesaemia of 0.09 mmol/l (normal range 0.65 to 1.05 mmol/l). Her serum calcium was 1.91 mmol/l (2.0 3 to 2.63 mmol/l). Hypomagnesaemia can cause generalized convulsions but is usually associated with hypocalcaemia. This patient had an almost normal serum calcium level and therefore hypomagnesaemia would seem to have been the direct cause of h er seizure. Long-term intravenous magnesium was necessary to prevent furthe r seizures.