Endocrine Abstracts

Introduction: Hyponatraemia is the commonest inpatient electrolyte abnormality and its severity correlates with inpatient mortality, length of stay and use of hospital resources. Frequently, hyponatraemia is not sufficiently acknowledged in the acute medical setting. The aim of this audit was to evaluate the investigation and management of hyponatraemia in a district general hospital.

Methods: Seventy-seven hyponatraemic patients (Na<135 mmol/l) were identified retrospectively over six consecutive months from medical admissions take lists, where the inclusion criteria were those coded as ‘hyponatraemia’. The cohort comprised 12 males and 15 females, with a mean age of 70 years. Key diagnostic investigations to determine the cause of hyponatraemia were evaluated and subsequent management was reviewed. The data were compared with the standard investigations and management of the European Society of Endocrinology guidelines.

Results: 7.4% of the cohort had mild hyponatraemia (130–135 mmol/l), 18.52% had moderate hyponatraemia (125–129 mmol/l), 74.07% had severe hyponatraemia (<125 mmol/l). Only 48.15% were assigned an aetiology, the commonest being drug-induced hyponatraemia. Urinary sodium, plasma osmolality and urinary osmolality were measured in 7 (25.93%), 12 (44.44%) and 8 (29.63%) patients, respectively. Serum cortisol and thyroid function tests were measured in 10 (37.04%) and 21 (77.78%) patients, respectively. 81.48% were discharged hyponatraemic (<135 mmol/l), with half of these less than 130 mmol/l. None of the patients were referred to endocrinology (excluding two who were admitted under the endocrinology take). Only one patient had a follow-up blood test to re-check serum sodium post discharge.

Discussion: In a hospital population, only a minority of patients with hyponatraemia were appropriately investigated according to standard guidelines. This audit has identified hyponatraemia, a clinical entity associated with prolonged hospital stay, as poorly managed. Education of all medical staff, accompanied by practical guidelines highlighting investigation and management, are pivotal.