Symptoms, causes, management and outcomes of hyponatraemia: a single centre study among hospitalised adult patients in Malaysia

Background Hyponatraemia is a common electrolyte abnormality seen in medical admissions. To date, there is no hospital-wide local study on hyponatraemia across the young, middle and older age groups. We evaluated the clinical features, aetiology, and outcomes of patients admitted in a tertiary hospital when hyponatraemia was noted as part of initial investigations. We also reviewed the documented management, aiming to promote local guideline development for hyponatraemia. Methods A retrospective study based in Hospital Sultan Ismail (HSI) Johor Bahru was undertaken between January 2020 to December 2022 on adults admitted with a serum sodium (Na) level of <135mmol/L. Patients were identified through the electronic database. Results 165 patients (mean age 64.4 ± 12.9, 52.6% females, 42.4% males) were diagnosed with mostly moderate or severe hyponatraemia. Severe hyponatraemia was significantly more prevalent among elderly patients (p= 0.002). Loss of appetite, generalised weakness and vomiting were the common presentations. 27.9% of patients were identified based on laboratory results without symptoms of hyponatraemia. The main causes of hyponatraemia were poor oral intake (20.6%), multifactorial (18.8%) and diarrhoea and vomiting (14.5%). Majority received 0.9% sodium chloride (NaCl) infusion. 18 patients (10.9%) have ≥10 mmol/L Na increment over the first day without complication. The overall mortality rate was 4.85% over 3 years. Conclusions Hyponatraemia may present with non-specific symptoms in hospitalised patients. Early recognition and management are required to avoid complications. Larger prospective studies to further explore the clinical profile of hyponatraemia among local patients will aid in protocol development to optimise patient outcome.