Incidence and risk factors of overcorrection in patients presenting with severe hyponatremia to the emergency department

Background Hyponatremia is one of the most common electrolyte abnormalities. Overcorrection of severe hyponatremia can result in serious neurological complications such as osmotic demyelination syndrome, but the incidence and risk factors of overcorrection and osmotic demyelination have not been thoroughly investigated. Methods This is a single-center retrospective cohort study of 50 patients admitted through the emergency department with initial serum sodium (serum Na) < 125 mEq/L between January 2015 and December 2017. Incidence and risk factors of overcorrection and osmotic demyelination were examined. Overcorrection was defined as an increase in serum sodium concentration > 10 mEq/L at 24 h and/or > 18 mEq/L at 48 h, respectively. Results Six patients (12%) and one patient (2%) had overcorrection at 24 h and 48 h, respectively. A total of 5 (10%) patients had a brain MRI completed after overcorrection, and no patient showed radiologic evidence of osmotic demyelination. Symptomatic hyponatremia at presentation and 3% saline use were associated with the risk of overcorrection in univariable analysis (p < 0.001; p = 0.006, respectively). Conclusions Among patients admitted with severe hyponatremia, overcorrection occurred in 14%. Symptomatic hyponatremia at presentation and 3% saline use were associated with the risk of overcorrection.