Endocrine Abstracts

In a retrospective cohort study, we reviewed the medical notes of patients with severe hyponatreaemia admitted to acute medical unit at Blackpool Hospital between January and March 2012. We assessed the severity, causes of hyponatraemia, length of stay and mortality in patients with hyponatraemia.

We identified 25 patients with plasma sodium ≤120 mmol/l, 5 of whom were admitted twice during the study period. Their average age was 70 (range 30–91) years, 16 were female and 9 were males. Three of them with sodium <110 mmol/l and the others had sodium 110–120 mmol/l. Twelve patients (48%) had acute hyponatraemia, eight patients (32) had subacute hyponatraemia of <6 months duration, and five patients (20%) had chronic hyponatraemia for more than 6 months duration.

Reasons for admission include confusion in 24% of patients, collapse in 20%, falls in 20%, and vomiting 8%.

Elven patients (44%) were found to have hypovolaemic hyponatraemia, nine patient had hypervolaemic hyponatraemia related to heart and liver diseases, and five patients had normovolaemic hyponatraemia related to SIADH related to drug therapy.

Hyponatraemia was corrected within a week in eight patients (32%), and was corrected between 1 and 4 weeks in seven patients (28%), and never corrected in seven patients.

Length of hospital stay was less than a week in 13 patients (56%), and 44% of patients stayed for more than a week. Mortality was 16%.

Severe hyponatraemia in acute medical admission is associated with prolonged length of hospital stay, and high mortality.