MON-274 Primary Aldosteronism in a Patient with 20 Years of Uncontrolled Hypertension: A Case of Non-Lateralizing Adrenal Adenoma

Abstract Disclosure: V. Florova: None. K. Mercene: None. P. Oli: None. E. Georges: None. Primary aldosteronism (PA) accounts for 10–25% of secondary hypertension cases but remains underdiagnosed due to variable clinical presentations, often reaching recognition later in life. Early identification is critical to preventing complications such as cardiovascular and chronic kidney disease. Notably, hypertensive patients with obstructive sleep apnea (OSA) are at increased risk of PA, further complicating management. We present a 48-year-old female with resistant hypertension, end-organ damage (chronic kidney disease), PA, and OSA in the setting of a 20-year history of poorly controlled postpartum hypertension. Initially diagnosed at 28 years old, she responded well to enalapril monotherapy. Two years later, her hypertension became refractory, necessitating the addition of hydrochlorothiazide. She remained normotensive for nearly 18 years but later developed uncontrolled hypertension despite maximized doses of enalapril, hydrochlorothiazide, amlodipine, and carvedilol. Re-evaluation revealed OSA, and she was started on weight management and positive airway pressure therapy. Despite these interventions, her hypertension continued to be resistant, and she developed a decline in kidney function (GFR 58–62 mL/min/1.73m²) without albuminuria secondary to hypertensive nephrosclerosis.For further assessment, she was referred to nephrology, where repeat secondary hypertension workup revealed an aldosterone-to-renin ratio of 14.1/0.4, consistent with PA. Abdominal CT and MRI identified a 1.8 cm left adrenal nodule, appearing as a benign adenoma. Adrenal venous sampling (AVS) failed to demonstrate lateralization, ruling out surgery. She was started on spironolactone, achieving blood pressure control with spironolactone 400 mg daily and nifedipine 60 mg daily. Biochemical testing excluded autonomous cortisol secretion and pheochromocytoma.This case underscores the importance of comprehensive evaluation in resistant hypertension and OSA, including repeat imaging and biochemical testing. It also highlights the importance of AVS in patients older 35 years old as risk of non-secretory adrenal adenoma increases. In non-lateralizing PA, mineralocorticoid receptor antagonists remain the cornerstone of treatment. Through this report, we emphasize the importance for timely involvement of multidisciplinary care to optimize outcomes and mitigate long-term complications associated with PA. Presentation: Monday, July 14, 2025