Prevalence of adrenal insufficiency among patients with euvolemic hyponatremia

Abstract

Background: The diagnosis of syndrome of inappropriate anti-diuresis requires the exclusion of secondary adrenal insufficiency (AI) among patients with euvolemic hyponatremia (EuVHNa). Studies have suggested that about 2.7–3. 8% of unselected patients presenting to the emergency room with EuVHNa have undi agnosed AI and it is as high as 15% among patients admitted to specialized units for evaluation of hyponatremia. Objective: To study the prevalence of AI among in-patients with EuVHNa in a general medical ward setting. Methods: This was a prospective, single-center observational study cond ucted among general medical in-patients with EuVHNa, defined as patients wit h a serum sodium 30 mmol/ L. Additionally, patients with recent vomiting, current renal failure, diuretic use and those with uncontrolled hyperglycemia were excluded. Adrenal functions were assessed by a modified adrenocorticotropic hormone (ACTH) stimulation test c alled the Acton Prolongatum™ stimulation test (APST). A cut-off cortisol value o f <18 mg/dL after 60 min of ACTH injection was used to diagnose AI. Results: One hundred forty-one patients were included and underwent an APST. APST suggested 20/141 (14.2%) had undiagnosed AI. The commonest caus e of AI (9/20) was secondary AI because of the use of steroids including inhaled steroids and indigenous medicines contaminated with steroids. In 5 (3.5%) patients hypo pituitarism was newly diagnosed. Despite primary AI (PAI) not commonly presenting as EuVHNa, 2/20 patients had PAI. Conclusions: AI is much commoner in our country, among in-patients with EuV HNa primarily driven by exogenous steroid use and undiagnosed hypop ituitarism.

Keywords

• hyponatremia
• euvolemic hyponatremia
• adrenal insufficiency
• secondary adrenal insufficiency
• hypopituitarism