Diagnostic Challenges of Adrenal Venous Sampling for Primary Hyperaldosteronism in a Patient With Subclinical Cushing's Syndrome: A Case Report

Hypertension is a significant comorbidity in the New World, and its prevalence is rising. Around 5%-10% of cases with hypertension have secondary hypertension. Adrenal gland disease is among the common causes of secondary hypertension. We present a 57-year-old male with uncontrolled hypertension and a history of intracranial hemorrhage. The lab evaluation of the patient revealed a K+ of 3.8 mEq/L, Na + of 138 mEq/L, Renin of 2.6 mIU/L, Aldosterone of 47.3 ng/dL, consistent with primary hyperaldosteronism (PHA). The patient's abdominal computed tomography (CT) revealed an adrenal mass measuring 21 mm in the right adrenal gland. However, the adrenal-vein sampling showed that the mass is probably not the source of aldosterone excess, and a possible diagnosis of adrenal hyperplasia was made. To investigate the adrenal incidentaloma, the 1 mg overnight dexamethasone suppression test was performed. The 8 a.m. cortisol and ACTH levels were reported to be 5 microg/dL and 3.2 pg/mL, and a diagnosis of mild autonomous hypercortisolism was also made. CT is not an accurate method to differentiate between an adrenal-producing adenoma and bilateral idiopathic adrenal hyperplasia. Even in cases where a visible mass is detected on CT, patients aged 35 or older need to be evaluated for the cause of PHA.