H2O coma

Water intoxication is a rare cause of coma. The leading causes of excessive hydration are endurance exercise, drug abuse, iatrogenic, cerebral salt wasting, or psychiatric conditions. Self-induced water intoxication in an otherwise healthy person is exceedingly rare.

Single patient case report and review of the literature.

We describe a previously fit and healthy 13-year-old girl who was admitted to the Accident and Emergency department in a comatose state following an unwitnessed seizure. On examination she had a fluctuating Glasgow Coma Score, bilateral mydriatic pupils that responded poorly to light, and an upgoing right plantar. Blood pressure, pulse rate, and oximetry, as well as body mass index, were normal. Routine blood examination revealed hyponatremia, hypochloremia, and a low hematocrit. Water intoxication was suspected and confirmed by reduced urine sodium, serum, and urine osmolality. The computed tomographic brain scan, lumbar puncture opening pressure, and cerebrospinal fluid examination were all normal. She regained consciousness and was fully orientated within 24 hours following intravenous NaCl administration. In this case, thirst without any other apparent pathology led to voluntary water intoxication.

Our case illustrates the classic picture of self-induced water intoxication in a previously fit and healthy patient.