Profile of hyponatremia in a tertiary care centre in North India

Abstract

INTRODUCTION Hyponatremia defined as serum sodium less than 135 meq/l is the most common electrolyte disorder among hospitalized patients. 1-5 It is associated with mortality and morbidity ranging from 5-50 % depending on severity and acuity of onset. 6 Hyponatremia occurs in a broad spectrum of patients. It affects all age groups and both sexes equally but is most commonly found in elderly persons because of an increase frequency of comorbidities, that can lower serum sodium levels (example cardiac ,hepatic or renal failure). 7-9 Patients in whom the serum sodium concentration is greater than 130 mEq/L are usually asymptomatic, whereas those in whom these values are lower may have symptoms. Symptoms occurring early in hyponatremia are usually anorexia, nausea, vomiting. Some patients may have headache and irritability. As serum sodium levels falls further patients develop neuropsychiatry symptoms. These symptoms range from restlessness, altered consciousness, lethargy, seizures to coma. There ABSTRACT Background: Hyponatremia is the commonest electrolyte imbalance. Hyponatremia is a heterogenous disorder and classified into hypovolemic, euvolemic and hypervolemic types depending on the volume status of the patient. Approach is based on etiology and type of hyponatremia. The aim of the present study was to determine the profile of hyponatremia in adult patients including underlying etiology, type, clinical features and outcome Methods: The study was conducted at BRD medical college Gorakhpur, India between July 2014 to August 2015 after approval by the ethical committee. Consenting patients >18 years of age with hyponatremia (<130meq/l) were included and investigated as per protocol. Based on volume status and urinary sodium patients were classified as euvolemic, hypervolemic and hypovolemic. Results: N = 250, mean age 53.9 years. 56% males, 154(61.6%) patients had euvolemic, 53 (21.2%) hypervolemic and 43(17.2%) hypovolemic hyponatremia. The most common causes for euvolemic, hypervolemic, hypovolemic hyponatremia were CNS infections, CLD and acute gastroenteritis respectively. Neurologic symptoms were more common in severe as compared to mild hyponatremia (69.7% versus 8.1%). Seizures attributable to hyponatremia were seen in 44 patients (17.6%), all with severe hyponatremia. Overall mortality was 14%. Deaths were more frequently seen in patients with severe hyponatremia as compared to patients with mild hyponatremia (25.5% vs. 4.7% P = 0.035). Conclusions: Euvolemic hyponatremia is the most common type seen in hospitalized patients and is associated mainly with intracranial pathologies. Severe hyponatremia is significantly associated with neurological manifestations and higher mortality.