title: A case of water intoxication with prolonged hyponatremia caused by excessive water drinking and secondary SIADH.
abstract: Water intoxication is a life-threatening disorder accompanied by brain function impairment due to severe dilutional hyponatremia. We treated a 22-year-old man without psychotic illness who had been put in a detention facility. He drank 6 liters of water over a 3-hour period at the facility as a game's penalty, and he showed progressive psychiatric and neurological signs including restlessness, peculiar behavior and convulsions. On his admission, 15 h after the discontinuation of the water drinking, he was in a coma, showing intermittent convulsions and remarkable hyponatremia (120 mmol/l). Because his laboratory tests showed hypertonic urine and normal sodium excretion, the diagnosis of secondary development of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) was strongly suggested and later confirmed by the suppression of the renin-aldosterone system and the inappropriately elevated secretion of ADH. Saline infusion and an initial administration of furosemide in addition to dexamethasone as treatments for the patient's brain edema successfully improved his laboratory data and clinical signs by the 3rd hospital day, and he was returned to the facility without physical or psychiatric abnormalities on the 6th day. The secondary SIADH might have been due to the prolonged emesis, recurrent convulsions and rapid elevation of intracranial pressure.
authors.affiliation: Sekishinkai Sayama Renal Clinic, Sayama, Saitama Medical University, Kawagoe, Ranzan, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Yamashiro
authors.affiliation: Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Ranzan, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Hasegawa
authors.affiliation: Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Ranzan, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Matsuda
authors.affiliation: Faculty of Health Science, Tokyo Metropolitan University, Tokyo, Ranzan, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kinoshita
authors.affiliation: Musashi-Ranzan Hospital, Ranzan, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsumura
authors.affiliation: Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Ranzan, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Isoda
authors.affiliation: Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Ranzan, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mitarai
keywords: Free water clearance; Hyponatremia; SIADH; Water intoxication