Abstract
Background: Hyponatremia, defined as a serum sodium concentration <135 mmol/l. It may be asymptomatic or present with symptoms ranging from nausea, lethargy to seizure and coma or even life threatening. Timely diagnosis can result in appropriate interventions to reduce these symptoms and mortalities.

Aims and Objective: To evaluate the causes and clinical features of hyponatremia in hospitalized patients.

Material and Methods: Present study was observational study. Patient aged 14 years and above with serum Na+≤130 meq/l were included in study. Based on history and clinical examination patients were classified as hypovolemic hyponatremia, hypervolemichyponatremia and euvolemic hyponatremia. Patients with clinical euvolemia, Urine Na+>20 mmol/l, Serum uric acid ≤4 mg/dl, normal renal function (serum creatinine and blood urea) and absence of thyroid or pituitary insufficiency were classified as having Syndrome of inappropriate antidiuresis (SIAD). The sodium estimation was done in the randox automated analyser which measures sodium by ion selective electrode technology.

Results: A total of 100 patients with hyponatremia (serum Na+≤130 mEq/L) were included in the study. The mean age of presentation was around 51.5 ± 17.5 years with male to female (M:F) ratio 1.8:1. Severe hyponatremia was detected in 56 patients and the mean sodium level was 118.2 ± 8.1 mEq/L. 43 patients had altered level of consciousness in form of drowsiness, confusion, irrelevant talking or coma, 6 patients had seizure, 38 patients had vomiting, 7 patients had hiccups and 38 hyponatremic patients were asymptomatic. The commonest type of hyponatremia noted in our study was euvolemic hyponatremia (71%) followed by hypervolemic (27%) and hypovolemic hyponatremia (2%). Most the euvolemic hyponatremiain in our study were due to SIAD (94.4%).

Conclusion: Commonest age group for hyponatremia was 60–69 years. Majority of the patients fell in euvolemic group followed by hypervolemic. Most common presentation of hyponatremia was altered sensorium, vomiting and few patients had seizure.

Key words: Hyponatremia; Syndrome of Inappropriate Antidiuresis; Altered Sensorium; Electrolyte