Hyperaldosteronism Presenting as Pre-syncope: A Case Report

Primary Aldosteronism (PA) is a common but often underrecognized cause of secondary hypertension. While typically associated with hypokalemia, profound muscle weakness is rarely a presenting symptom, especially in the absence of significant electrolyte derangement. We present a case of a 65-year-old male with hypertension and dyslipidemia who presented with transient acute attacks of profound weakness and presyncope, without loss of consciousness or other focal neurologic signs. Initial evaluation, including cardiac, neurologic, and metabolic testing, was unrevealing. Mild hypokalemia (potassium 3.2 mmol/L) was noted on admission. Further endocrine workup revealed a suppressed plasma renin activity (0.5 ng/mL/hr) and elevated plasma aldosterone concentration (28.3 ng/dL) with a high plasma aldosterone concentration/plasma renin activity (PAC/PRA) ratio (56.6), suggestive of PA. Imaging identified two left adrenal gland nodules (4 mm and 6 mm) consistent with adenomas, and adrenal venous sampling demonstrated left-sided predominance. The patient underwent a unilateral retroperitoneoscopic adrenalectomy with complete resolution of symptoms. Prior to surgery, he was treated with amlodipine 10 mg daily and prazosin 1 mg twice daily for blood pressure control. Following adrenalectomy, he maintained normotension without antihypertensive therapy, which persisted at five-year follow-up. This case highlights a rare presentation of PA with episodic severe muscle weakness in the absence of profound hypokalemia. It underscores the importance of considering PA in patients with unexplained episodic weakness and resistant or moderate-to-severe hypertension, even when potassium levels are within normal or mildly low ranges.