Incidence of hyponatraemia in the emergency unit

Hyponatraemia is an electrolyte disorder, defined as a serum sodium concentration (Na) <136 mmol/L. It occurs in up to 30% of hospitalised patients. The purpose of this study was to evaluate the frequency of hyponatraemia among all patients during a one month period in the emergency unit. During the one month period in 2014, 570 patients were included in this study. The study was approved by local ethics com-mittees and patients provided written in-formed consent. Out of the 570 patients, 41 (7%) had hy-ponatraemia. The median age was 67 (65.02±14.09) years and the majority of the patients were men (M:F = 23:18; 56.1:43.9%). Mild hyponatraemia (serum Na 130-135 mmol/L) was found in 71% (29/41), moderate (serum Na 125-129 mmol/L) in 17% (7/41), severe (serum Na 120-124 mmol/L) in 5% (2/41), and ex-tremely severe (serum Na< 120 mmol/L) in 7% (3/41) of patients. The treatment options included the restriction of fluid intake by administering hypertonic saline and loop diuretics.We should be alert to acute hyponatraemia, especially in elderly patients with neuro-logical manifestations and poor progno-sis. The presented data are an important contribution to the better understanding of the epidemiology of hyponatraemia in Croatia.