Primary hyperaldosteronism: Challenges in subtype classification

Background: Primary hyperaldosteronism (PA) is a serious and potentially debilitating disease. Detailed guidelines have been written to guide endocrinologists in establishing the diagnosis of PA as well as in subtype classification of PA. The objective of this case report is to present a case where subtype classification of PA was challenging and repeated imaging of the adrenal glands helped establish the diagnosis in a patient with initial normal adrenal glands on CT and MRI images. Case presentation. We report a case of a 29-year-old woman with an established diagnosis of PA, but unclear subtype, who presented to us for further management. She initially presented for medical evaluation of uncontrolled hypertension and spontaneous hypokalemia 4years prior. In the investigation of secondary causes of hypertension, plasma aldosterone-to-plasma renin activity ratio was elevated on two separate occasions, and primary hyperaldosteronism was confirmed by saline infusion test. Also during this time, she had adrenal venous sampling done 3 times at multiple institutions yielding confusing results. Initially, imaging by CT and MRI showed normal adrenal glands. To help establish the subtype of PA, we reimaged this patient's adrenal glands one year later revealing a 2cm left adrenal adenoma. Laparoscopic left adrenalectomy improved her hypertension and was curative of her hypokalemia. Conclusion: This case presents an unusual case where reimaging of the adrenal glands led to the discovery of a single adenoma, initially not observed on imaging studies.