Endocrine Abstracts

Objective: To audit the investigation and diagnosis of severe hyponatraemia (serum sodium ≤125 mmol/l) in elderly (age ≥65 years) medical in-patients admitted with this problem.

Method: Standards for the investigation and diagnosis of hyponatraemia were designed after literature review and discussions with local endocrinologists. Elderly patients with hyponatraemia on admission were identified retrospectively over a 12 month period from the laboratory database. Data from notes and computer records were extracted on to proformas and analysed.

Results: Thirty-six of 48 patients identified (75%) were studied. The mean age was 79.8 years, 66.7% were female and 6 month mortality was 47%. Serum osmolality, urine osmolality and urine sodium were investigated in 61, 53 and 31% of patients, respectively. Further tests such as thyroid function tests (50%), cortisol levels (44.4%), synacthen tests (2.8%), triglyceride (16.7%) and immunoglobulin levels (16.7%), were underperformed. Fifty-six percent of patients did not have a cause for hyponatraemia diagnosed in their medical notes with medication, pneumonia and fluid overload being attributed to 25, 6 and 3% of cases, respectively. On retrospective analysis, the cause of hyponatraemia was diagnosed in 75% cases and was attributed to medications, pneumonia and fluid overload in 31, 19 and 14% of cases, respectively. In 41.7% of patients, there were no documentation of hyponatraemia in their discharge summary.

Discussion: Adequate investigations for hyponatraemia were under performed. The causes of hyponatraemia were under reported highlighting the diagnostic challenge that this condition poses to clinicians. Poor documentation of this condition in medical notes and discharge letters was noted.

Conclusion: Severe hyponatraemia is a serious but poorly investigated and often ignored condition. We hope to improve our performance of investigating, diagnosing and documenting this common condition by using our audit findings to target education and develop local guidelines.