Management and outcome of symptomatic hyponatremia in emergency department

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Introduction

Severe symptomatic hyponatremia was thought to be extremely dangerous. It is recommended that acute hyponatremia should be treated without delay and rapidly at a rate of at least 1 mmol/l/hour. Symptomatic hyponatremia was said to lead to death or permanent brain damage. However, some authors did not support quick correction and suggested that most deaths were caused by underlying diseases. We evaluated the clinical outcome of cases with symptomatic hyponatremia in terms of different management strategies in the emergency department.

Method

In the emergency outpatient department of a community hospital, Okinawa, Japan, we retrospectively collected adult cases of symptomatic hyponatremia (serum sodium <130 mmol/l) from April 1995 to October 1999. Etiology, treatment and clinical outcomes were evaluated. Neurological sequelae were assessed in all cases.

Result

Eighty-two cases of hyponatremia were determined (mean age, 54 years old, 48 males and 34 females). The mean sodium level was 118 mmol/l (the lowest 104 mmol/l). There were 45 cases with consciousness disturbance and 33 cases with seizure. Fifty-three cases were acute and 29 chronic. Underlying etiology included water intoxication, SIADH and hypoadrenalism. Death occurred in four cases and all were caused by underlying diseases. Thirty-five cases were treated with isotonic saline, 15 cases with hypertonic saline, and 32 cases with no active fluid treatment. Although correction rate for hyponatremia was not rapid (<0.6 mmol/l/h) for all cases, there were no cases of mortality and neurological sequelae from hyponatremia.

Conclusions

Slow correction of serum sodium was not complicated with permanent brain damage from acute symptomatic hyponatremia. Rapid correction is not necessary for treatment of symptomatic hyponatremia just because the serum concentration is extremely low.