A case of acute water intoxication showing triphasic waves on EEG

We reported a case of acute water intoxication from compulsive water-drinking, who showed triphasic waves on EEG. The patient was a 50-year-old man who had been undergoing medical treatment in a mental hospital since he was suffering from schizophrenia diagnosed at the age of 35. He had sometimes had a tendency to drink a large amount of water since 45 years old. He began to drink water compulsively since three days ago. He vomited just after he drank excessive water with his mouth directly to the tap for several minutes, and soon fell into loss of consciousness. He was transmitted to our hospital because of acute consciousness disturbance on the next day. On neurological examination, he was profoundly comatose with miosis and conjugate deviation to the right side. His extremities showed decorticate posturing. On admission, serum sodium level was 101 mEq/l, and plasma osmolality was 208 mOsm/l. Serum enzymes derived from muscle and myoglobin were markedly elevated. But there was no laboratory evidence of the other metabolic disorders such as hepatic or renal disease. Computed tomography of the brain disclosed severely diffuse swelling with largely obliterated sulci and narrowed ventricles. EEG showed triphasic waves predominantly over centro-parieto-occipital portion, behind which there was slow wave activity with a loss of normal alpha wave activity. Immediately, treatment began by a combination of saline and glyceol infusion for the purpose of correcting severe hyponatremia, subsequently removing brain edema. As serum sodium level gradually returned to normal, the brain CT findings were getting better.(ABSTRACT TRUNCATED AT 250 WORDS)