Extreme sodium derangement in a paediatric inpatient population

Objective: To determine the aetiology, symptoms and outcome of extreme sodium derangement in a paediatric inpatient population. Methodology: A retrospective study of children with extreme disturbance of their plasma sodium (greater than or equal to 165 mmol/L or less than or equal to 115 mmol/L) admitted to a tertiary referral centre during a 72-month period. Results: Twenty-seven cases of hypernatraemia and 21 of hyponatraemia were reviewed. Sodium disturbance developed after hospital admission in 27/57 cases (57%). Gastroenteritis was the most common cause of hypernatraemia (8/27; 30%), four of 27 (15%) had iatrogenic hypernatraemia. Water overload accounted for 8/21 (38%) cases of hyponatraemia. Neurologic symptoms occurred in 19/24 (79%) with hypernatraemia and in 11/19 (58%) with hyponatraemia. Ten (37%) with hypernatraemia and four (19%) with hyponatraemia died. A deterioration in functional status was seen in two patients with hypernatremia. There was no apparent deterioration in the survivors with hyponatraemia. Conclusion: Extreme sodium disturbance often develops after admission to hospital and is caused by a variety of diseases and interventions. Neurologic symptoms are common and the mortality rate is high. The outcome in survivors is most likely to be dependent on the underlying disease process.