Endocrine Abstracts

Background: Hyponatraemia is the most common electrolyte abnormality, encountered in up to 30% of inpatients. Inappropriate management can have serious implications for patients; including demyelinating disease, coma, and death.

Methods: Patients (n=122) admitted to the medical admission unit of a district general hospital with a serum sodium (Na) <130 were selected for the study. All details including patient demographics, blood biochemistry, date of admission and date of death were taken from the case notes and hospital computerised system. Details on assessment of hyponatraemia including thyroid, adrenal and renal function were also recorded.

Results: Mean age was 70.4+18.1 years; 48 males. Mean serum Na on admission was 125.8+4.1 mmol/l. Of the 122 patients, 38 died (31.1%) in hospital. Patients who died were older (66.7±18.9 vs 72.3±15.3; P=0.054) Admission serum Na and plasma glucose in survivors vs died was 127.2±3.9 vs 124.2±4.7 mmol/l (P<0.001); and 7.0±3.0 vs 5.4±2.2 mmol/l (P=0.02) respectively. Patients with admission serum Na <125 in the survivors vs died was 32.1 vs 66.7%. Patients investigated for hyponatraemia were as follows: serum cortisol (n=6), plasma osmolality (n=9), urine osmolality (n=9), short synacthen test (n=0),urine sodium (n=3), thyroid function tests (n=19). Conclusions: Patients admitted with acute medical conditions with severe hyponatraemia have a high mortality and those with lower serum sodium have greater risk of death. Patients were also inadequately worked up for assessment of cause of the hyponatraemia and further education of medical specialists is urgently required to improve management and outcome. Also lower admission plasma glucose was associated with higher mortality.