Profound Hyponatremia: Prevalence, Underlying Disorders and Outcome in Tertiary Care Hospital.

ABSTRACT

Background: Profound hyponatremia (<125 mmol/l) is a serious electrolyte disturbance often encountered in tertiary care setting and is associated with increased morbidity and mortality. Does hyponatremia per se or the underlying disorder contribute to increased mortality remains a controversial point. Clinical records of profound hyponatremia patients were explored with the aim of finding its cause and contribution of hyponatremia in final outcome. Materials and Methods: All the inpatients with serum sodium ≤125 mmol/L were identified from laboratory data over a period of four months in a tertiary care hospital. Outpatients and cardiac patients were not included in the study. They were classified into three groups according to serum sodium levels in mmol/l (group I 121-125, group II 116-120, group III ≤115). Clinical data was obtained from medical record office. Clinical diagnosis, extent of hyponatremia correction and mortality rates were studied. Observations One thousand and fifty patients were identified as having profound hyponatremia (sodium ≤125 mmol/l). Prevalence of profound hyponatremia was recorded as 6.35%. Majority of profound hyponatremic patients (70.54%) had sodium levels in range of 121-125 mmol/l. Very profound hyponatremia (≤115 mmol/l) was noted in 17.6% patients. Mortality rate was significantly higher than the general mortality rate of hospital during that period (8.83% vs 4.6%, p < 0.001). Mortality in group III was highest (12%) followed by patients in group-I (8.42%). Most common cause of hyponatremia was chronic liver disease (20.9%), followed by infectious disease (17.04%), chronic and acute renal disease (15.4%). Diabetes mellitus along with its complications and endocrinological cause were present in 12.1% patients. Other causes include malignancy (11%), neurological (7.04%), pulmonary and trauma (6.4% and 5.17% respectively). Some miscellaneous causes like burns, psychological, skin disease were also noted. It was observed that patients died mainly because of underlying disease as in majority of subjects (75.72%) hyponatremia was corrected either fully or partially (Na≥ 130 mmol/l and Na ≥ 125 respectively) before demise. Conclusion: High prevalence of hyponatremia was recorded in inpatients making it a common electrolyte disturbance. Underlying disease and severity of hyponatremia have a bearing on final outcome of patients.