Endocrine Abstracts

Inpatients with hyponatraemia have a high mortality and longer length of stay. We instituted a system of automatic referral to the endocrinology team where any inpatient with a serum (Na⁺) ≤125 mmol/l was referred automatically from their biochemical results.

Aims: We evaluated the diagnosis, management, and outcome of the patients referred with hyponatraemia over 6 months.

Methods: Data were prospectively captured electronically. We recorded demographics, discharge diagnoses, serum (Na⁺) level, osmolalities, urinary electrolytes, thyroid function test (TFT), and cortisol status. Patients were categorised according to their initial volume status and final endocrine diagnosis. Interventions were: fluid restriction, N/Saline, hypertonic (1.8%) saline +/− furosemide or tolvaptan. Outcomes were recorded as time to sodium correction, length of stay and discharge status.

Results: 61 patients were referred of whom 56 were actively managed by the endocrine team. ‘True’ hyponatraemia was identified in 54/56 patients. They were classified as: hypovolaemic (22.2%), hypervolaemic (25.9%), and euvolaemic (51.9%). Cortisol status was recorded or established in 81.5% and TFTs in 88.9%. Of the euvolaemic patients (28/54), 25 had SIADH-including two patients newly diagnosed with cancer; 2/28 had gluco-corticoid deficiency; one low solute intake. In patients with hypervolaemia, 42.9% were treated with fluid restriction alone and 42.9% received diuretic and hypertonic saline. 66.7% of hypovolaemic hyponatremia patients corrected with 0.9% saline alone. Amongst 25 SIADH patients, nine responded to restriction +/− drug withdrawal alone, ten were corrected with hypertonic (1.8%) saline. Glucocorticoid replacement corrected hyponatraemia in two patients. Tolvaptan was needed in four cases. Correction of sodium ((Na⁺) ≥130 mmol/l) was achieved in 64.8% after a mean of 5 days.

Conclusion: Automatic referral to a specialist team from the laboratory was appropriate in >90% and led to a prompt diagnostic evaluation and active intervention.