SUN-427 - Life-Threatening Hypokalemia and Refractory Hypertension in A 24-Year-Old Male: A Rare Case of Unmasked Primary Aldosteronism

Background
Primary aldosteronism is a common cause of secondary hypertension, affecting an estimated 5 to 10% of adults with hypertension and up to 17 to 23% of those with resistant hypertension. In contrast, presentation with profound refractory hypokalemia, acute metabolic decompensation, and hypertensive emergency in young adults is rare in the published literature. We report a case of primary aldosteronism due to a unilateral adrenal adenoma in a 24-year-old male, unmasked by acute gastroenteritis that precipitated severe hypokalemia and hypertensive crisis, leading to definitive diagnosis and management. Primary aldosteronism presenting in childhood and early adulthood remains uncommon, with fewer than 25 cases reported, highlighting the wide but infrequently recognized spectrum of severe clinical manifestations associated with this disease.

Case Presentation
A 24-year-old male with long-standing early-onset hypertension and a known left adrenal adenoma presented with 48 hours of intractable nausea, vomiting, and diarrhea (>10 episodes), resulting in severe volume depletion, profound hypokalemia (serum potassium 1.9 mmol/L), and acute kidney injury (creatinine 1.8 mg/dL). He exhibited persistent hypertensive crisis with blood pressures up to 240/142 mmHg. Infectious and toxicologic workup was negative. Imaging showed a stable 13 mm unilateral left adrenal nodule; renal artery imaging excluded renovascular disease. Echocardiography revealed severe left ventricular hypertrophy with hyperdynamic systolic function (ejection fraction 70%) and apical cavity obliteration. Hypokalemia remained refractory to aggressive repletion (2.3–2.8 mmol/L). Endocrine evaluation revealed suppressed renin activity (0.10 ng/mL/h), aldosterone 20 ng/dL, and a markedly elevated aldosterone-to-renin ratio of 200. Plasma metanephrines, catecholamines, and a monogenic hypertension panel were normal.

Discussion
This case highlights a rare and extreme biochemical and clinical presentation of primary aldosteronism in a young adult. Although adrenal vein sampling remains the standard for subtype classification, it was deferred in this patient due to age under 35 years, spontaneous hypokalemia, a unilateral adrenal lesion, and elevated procedural risk, consistent with guideline-supported criteria. Multidrug antihypertensive therapy, mineralocorticoid receptor antagonism, and intensive potassium supplementation were required for preoperative optimization.

Conclusion
Severe manifestations of primary aldosteronism such as refractory hypokalemia and hypertensive crisis in young adults are uncommon in the literature. Early recognition and appropriate endocrine evaluation, including judicious use of adrenal vein sampling criteria, can facilitate timely diagnosis and definitive surgical management with optimized outcomes.

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