Acute hyponatriemia in a patient with schizophrenia: Case report water intoxication induced acute hyponatriemia

Introduction: Hyponatremia is defined as a serum sodium level higher than 135 mmol/L, while serum sodium level lower 125 mmol/L is considered as severe hyponatremia and can lead to coma, death, rhabdomyolysis, and neurologic damage. Case report: We present the case of a 34 year old male with history of schizophrenia with multiple seizures followed by loss of consciousness after intake of 6 liters of water. Diagnostic CT scan revealed cerebral edema. Laboratory tests revealed severe hyponatremia (109 mmol/l), hypokalemia and hypocalcemia. The patient was treated with 10% hypertonic NaCl 120 ml per day, 7.4% KCl and calcium gluconate. He was sedated and mechanically ventilated. Antiedematous therapy with mannitol 20% was started. The biochemical results improved slowly with gradual correction of the sodium level: 112 mmol/l, 119 mmol/l and 127 mmol/l respectively. CT scan showed cerebral edema regression was showed on repeated brain scan. On the 6th day sodium level was 131 mmol/l, and the patient was awake, oriented and extubated. Discussion: Psychogenic polydipsia occurs in 20% of the psychiatric patients which could lead to severe hyponatremia. Second generation antipsychotics intake could also lead to severe hyponatremia. According guidelines hyponatremia treatment consists of hypertonic NaCl 3% 150 ml infusion and frequent sodium levels measurements. The sodium level correction should be gradual and should not exceed more than 10 mmol/l for the first 24 hours neither more than 8 mmol/L for every next 24 hours. Conclusion: In our patient, serum sodium level correction was successfully and safely performed with hypertonic saline (NaCl 10%) in absence of hypertonic NaCl 3%. Strict control of serum sodium levels is a must in order to avoid osmotic demielinisation and rhabdomyolysis.