Unmasking Secondary Hypertension: Renal Artery Stenosis Concealing Primary Hyperaldosteronism

Introduction: In young adults with new onset hypertension, complete secondary workup is warranted. We present a patient ultimately found to have an aldosterone-secreting adenoma after a complex diagnostic journey. Case Description: A 21-year-old woman with no medical history was found to have elevated blood pressures (BP) in both the home and office setting. Lab values were significant for hypokalemia and metabolic alkalosis with elevated plasma aldosterone concentration (PAC) of 16.1, plasma renin activity (PRA) of 0.442, and aldosterone to renin ratio (ARR) of 36.4. Subsequent values were non-diagnostic (Table 1) with normal 24-hour urine aldosterone and CT abdomen negative for adrenal adenoma. Additionally, renovascular workup revealed focal right renal artery stenosis of 40% concerning for fibromuscular dysplasia. One year later, due to increasing BP, angiogram revealed ~73% stenosis therefore angioplasty was performed. This did not improve her HTN, thus she sought opinion from an outside renovascular specialist re-visiting the possibility of primary hyperaldosteronism. Reassessment of primary hyperaldosteronism revealed elevated PAC and ARR levels with Adrenal MRI revealing a 1.7cm left adrenal adenoma. Adrenal venous sampling (AVS) confirmed the presence of a hyperfunctioning adenoma. Surgical removal of the adrenal gland resulted in successful weaning of all BP medications. Discussion: We present a case with multiple confounders representing diagnostic dilemmas encountered with complex testing. Although the gold standard for diagnosing RAS is invasive angiography, the non-invasive tests such as doppler ultrasound and magnetic resonance angiography have reasonably high sensitivity and specificity. However, these tests are operator dependent which may impact reliability. Additionally, interpreting the plasma aldosterone and renin is nuanced with many factors affecting results including time of day, medications, and positioning of the patient. A multidisciplinary approach ultimately led to the diagnosis after an arduous evaluation. Table 1 - Date Aldosterone Renin Aldosterone/Renin Ratio 04/28/2020 16.1 0.442 36.4 05/18/2020 4.2 1.621 2.6 06/10/2020 10.7 0.402 26.6 04/15/2022 8.3 0.468 17.7 06/12/2023 23.1 1.783 13 07/10/2023 2.4 3.118 0.8