A Rare Find of Glucocorticoid-Remediable Aldosteronism

Introduction: Glucocorticoid remediable aldosteronism (GRA), is a rare genetic form of hyperaldosteronism caused by an unequal cross-over of steroid 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, leading to an increased aldosterone synthesis driven by ACTH. Here, we present a case of GRA diagnosed by ACTH stimulated adrenal vein sampling (AVS) and confirmed by genetic testing. Case Description: A 24-year-old female was referred for hypertension. She was found to have elevated blood pressure (BP) at age 16 after falling from a horse ride. At age 20, she was again hypertensive and developed mild hypokalemia. Since then, her BP has not been controlled on maximum doses of amlodipine, chlorthalidone, and lisinopril. She has no other medical history, is a nonsmoker, rarely drinks alcohol, never used illicit drugs. She was adopted. Her only compliant was involuntary 80 lbs weight gain over the past three years. Vitals: BP 150/98, heart rate 88 bpm; physical exam was unremarkable. Laboratory tests showed normal renal and liver functions, normal thyroid function, normal electrolytes except potassium 3.1 mEq/L, plasma renin activity was <0.1 ng/mL/hr, serum aldosterone was19.4 ng/dL; CT showed normal adrenal glands. Shortly after, ACTH-stimulated adrenal vein sampling (AVS) was performed which showed dramatic aldosterone responses to ACTH without lateralization (see Table). Genetic test confirmed pathogenic CYP11B1 and CYP11B2 fusion. She responded to low dose prednisone and spironolactone 50 mg twice a day. Discussion: GRA diagnosis is often overlooked due to fluid clinical presentations. Work up starts by confirming hyperaldosteronism. In this case, AVS was very helpful in securing the diagnosis with dramatic aldosterone response to ACTH. A prompt diagnosis of GRA is crucial to establish an effective treatment regimen. ACTH-stimulated adrenal vein sampling result - Pre-ACTH Post-ACTH IVC R Adrenal Vein L Adrenal Vein IVC R Adrenal Vein L Adrenal Vein Aldosterone (ng/dL) 1 14 14 41 5505 5279 Cortisol (mcg/dL) 1.7 5 4.3 10.5 321.6 320.7