Cerebral swelling in severe hyponatremia caused by water intoxication in a schizophrenic patient

A 41-year-old female suffering from water intoxication showing consciousness disturbance with a serum sodium level of 104 mEq/l followed by repeated seizures is reported. She had been treated for 16 years with the drug, chlorpromazine. The computed tomography (CT) showed a bilateral hemispheric swelling. This swelling improved after spontaneous urination with an amount of 6700 ml within the first 12 h. We postulate that severe hyponatremia is possibly life-threatening, moreover, it is hardly recognized if the past history or previous prescription record was not known, because the CT appearance is sometimes misinterpreted.