SAT298 Adrenal Insufficiency Presenting With Isolated Severe Hyponatremia: A Case Series

Disclosure: A. Shafi: None. J. Berardo: None. J. Hwang: None. Background: Adrenal insufficiency (AI) is an overlooked cause of severe hyponatremia (defined as serum Na <120); especially when it is not accompanied by other classic features (i.e., hypotension, hypoglycemia or other electrolyte dysfunction) leading to delayed diagnosis, treatment and increased length of hospital stay (LOS).Case series: We report 14 cases (9 distinct patients) of hospital admission for severe hyponatremia either on presentation or during course of hospitalization attributable to adrenal insufficiency. Four of the nine patients had multiple admissions. These cases were divided into 2 groups based on if they were newly diagnosed (n=6) or had a known diagnosis (n = 8) of AI. Mean age was 56 for both groups, serum Na was 117 vs 114, systolic BP was 126 vs 123. Endocrine was consulted on day 4.5 vs 1.8 and hydrocortisone was started on day 4.8 vs 1.3 resulting in length of stay 8 vs 5 days, respectively. 80% of the subjects also had hypothyroidism with a mean free T4 of 0.87 vs 0.71. In the newly diagnosed group, cortisol was checked on day 3.5. The majority (86%) of admissions were attributed to a secondary adrenal insufficiency crisis. Conclusion: This case series presents several important conclusions which impact endocrine consultation, treatment and length of hospital stay. A) Despite various hyponatremia guidelines suggesting ruling out AI and hypothyroidism before empirical diagnosis of SIADH, there can still be delay in checking cortisol status. B) AI presentation can lack hemodynamic instability or other electrolyte abnormalities so a high clinical index of suspicion should be exercised in diagnosing this potentially fatal condition when encountering isolated severe hyponatremia. C) There is a significant rate of readmission in cases of severe hyponatremia related to adrenal insufficiency. Presentation: Saturday, June 17, 2023