Endocrine Abstracts

Hyponatraemia is the commonest electrolyte abnormality in hospitalised patients. It is often seen in patients with complex medical problems and in the critically ill. We determined the outcome for patients identified to have hyponatraemia over a one month period.

Methods: We reviewed all in-patients with severe hyponatraemia, defined as serum sodium <125 mmol/l (135–146) at Hope Hospital during April 2005. Patients were identified retrospectively from laboratory computer data and case notes retrieved.

Results: We identified 336 patients with serum sodium <135 mmol/l of whom 40 had serum sodium <125 mmol/l. 36 were available for study, 4 from general surgical, 2 from neurosurgical and 30 from general medical wards. The median age was 66.5 years, range 43–90 years and median serum sodium was 113 mmol/l, range 102–124 mmol/l. Heart rate, blood pressure and chest examination were recorded in 100% but jugular venous pressure was assessed in only 17/36 (47.2%). 5/36 (13.9%) were stated to be ‘dry/dehydrated’ but there was no evidence that the patient’s tissue hydration had been assessed in any reliable way. Fluid balance was charted in 18/36 (50%). 8/36 (22.2%) were clinically hypovolaemic, 6/36 (16.7%) were hypervolaemic, and the remainder 22/36 (61.1%) were assumed to be euvolaemic. There was written evidence the patient’s medication had been reviewed in 28/36 (77.8%); potentially contributing medication was identified in 14 patients but only stopped in 8 patients. Mortality rate was surprisingly high at 31% (11/36) and of those who died 91% (10/11) patients were still hyponatraemic at death.

Conclusion: Many patients had not been assessed in enough detail to guide the management of this disease, which has a high mortality. Assessment of the tissue signs of hypovolaemia and jugular venous pressure was particularly poor. Hyponatraemia persisted in many patients and had a very high mortality rate.