SUN-470 Unilateral Disease Bilateral Consequences A Case of Persistent Hyperkalemia After Unilateral Adrenalectomy for an Aldosterone Secreting Adenoma

Abstract Disclosure: L.J. Adams: None. P. Ginier: None. Background: The bilateral consequences after a unilateral adrenalectomy for Cushing’s syndrome is well described in the literature, but not so with aldosterone secreting adenoma as this is very rare.57-year-old male with long standing hypertension, hypokalemia, and 1.6 cm right adrenal gland nodule. Aldosterone level of 108.7 (normal range 1.0-16.0 ng/dL), renin <0.5 (normal range <0.5 - < 3.4 ng/ml/hr.), BUN 13 (normal range 7-24 mg/dL), creatinine 0.9 (normal range 0.6-1.3 mg/dL), sodium 140 (normal range 136-145 mmol/L) potassium 3.5 (normal range 3.5-5.1 mmol/L) (while taking spironolactone and potassium supplements). Spironolactone and potassium supplements discontinued serum potassium at discharge post adrenalectomy 3.5. Potassium level initial post adrenalectomy clinic visit was 5.9 slight increase in BUN/Creatinine. Blood pressure 143/84 pulse 81 (only on metoprolol 200 mg per day). Patient verified he was not taking potassium supplements, spironolactone, salt substitutes, freeze dried coffee or other high potassium content foods. Sent to the Emergency department for hyperkalemia repeat potassium 6.3 treated with hydration and kayexalate post treatment potassium 5.4 aldosterone 5.8 renin <0.5 blood pressure 145/80 pulse 52 only taking metoprolol 200 mg per day (may contribute to hyperkalemia), but no other obvious cause. Hyperkalemia management (tapering down the dose of metoprolol, adding chlorthalidone to waste potassium, giving kayexalate when needed, and using calcium acetate to shift potassium intracellularly) to give time for the contralateral gland to recover functionally (arduous task for both patient and endocrinology staff). Potassium continued to be elevated renal function and bicarbonate levels were also declining (relative hypoaldosteronism and hyporeninemia) about 6 months after surgery aldosterone level of 8.5, renin <0.5, BUN 33, creatinine 2.0, sodium 139, potassium 5.8 continues to be in a state of relative hypoaldosteronism the decision was made to initiate low dose fludrocortisone. He remains on fludrocortisone with potassium levels mostly in the normal range now serval years post adrenalectomy. In conclusion: Adrenal insufficiency post unilateral adrenalectomy for aldosterone secreting adenomas is rare with little mention of this consequence in the literature or guidance for management other than monitor weekly potassium and if potassium continues to be elevated start fludrocortisone. Presentation: Sunday, July 13, 2025