Endocrine Abstracts

Introduction: Hyponatraemia is the commonest electrolyte disturbance occurring in 15–20% of inpatients (1), with significant clinical implications if mismanaged. We conducted a retrospective audit of our current management of hyponatraemia in our 1000 bedded trust.

Method: Data of patients with severe hyponatraemia (Na<125 mmol/l) admitted to hospital over 4 weeks (Aug 2011) was collected. Twenty randomly selected cases were reviewed focusing on initial assessment, management plan and associated morbidity.

Results: 218 cases were identified during the study period. Among the 20 selected cases, the lowest admission sodium was 112 mmol/l, the mean age was 73 years (29–90) with 30% female, the cohort was also noted to have multiple co-morbidities (M=4.56). Assessment of hyponatraemia was only mentioned in 10 (50%) cases on the consultant post take ward round. Fluid balance was recorded only in eight (44%) cases and no patient was assessed for postural hypotension. Aetiologies identified were as follows; idiopathic (42%), drug induced (26%), SIADH (26%) and hypervolaemic causes (6%). Of the SIADH group the following investigations were performed; urinary sodium (60%), urine osmolality (60%) and serum osmolality (80%), thyroid function tests (20%) and 0900 h cortisol (14%). In relation to outcomes, fall in serum sodium was seen in 25%, with a rise evident in 65%, one case having >10 mmol rise in 24 h. The mean length of hospital stay (LOS) was 16 days (4–56 days) in comparison with a trust mean of 5 days, with 15% of prolonged LOS documented to be attributable to hyponatraemia. Mean sodium on discharge was 130 mmol/l (121–137 mmol/l), one death occurred post discharge (Na 122 mmol/l).

Conclusion: Hyponatraemia is commonly seen in patients with multiple co-morbidities. Management remains challenging and attributes to prolonged LOS. A clear local guideline is needed and is currently under development, to improve the standard of care.

Reference

Huda MSB, Boyd A, Skagen K, Wile D, Van Heyningen C, Watson I, Wong S & Gill G. Investigation and management of severe hyponatraemia in a hospital setting. Postgrad Med J 2006 82 (965) 216–219.