Circulatory collapse caused by unnoticed hypermagnesemia in a hospitalized patient.

We report a case of hypermagnesemia in a hospitalized patient after prolonged laxative use; due to preexisting impaired consciousness and digestive problems, the hypermagnesemia was difficult to detect until it almost became fatal. A 64-year-old man who was a patient at another hospital for treatment of head injury and gastric ulcer had developed circulatory collapse and was transferred to our hospital. Hypermagnesemia (serum magnesium concentration 11.0 mg.dl(-1)) was thought to be the cause of the circulatory collapse and treatments were successful. A magnesium laxative had been administered for more than a month at the previous hospital, but the patient's serum magnesium level was never measured. Care should be taken when a magnesium laxative is administered to patients who already have impaired consciousness and digestive problems that are early symptoms of hypermagnesemia.