Resistant hypertension with adrenal nodule: are we removing the right gland?

Resistant hypertension is often difficult to treat and may be associated with underlying primary aldosteronism (PA). We describe the case of an elderly gentleman who presented with severe and resistant hypertension and was found to have a left adrenal incidentaloma during evaluation but had aldosterone excess secondary to unilateral adrenal hyperplasia (UAH) of the contralateral gland, which needed surgical intervention. A 65-year-old gentleman was evaluated for uncontrolled high blood pressure (BP) in spite of taking four antihypertensive medications. The high BP was confirmed on a 24-h ambulatory reading, and further biochemical evaluation showed an elevated serum aldosterone renin ratio (ARR) (1577 pmol/l per ng per ml per h). Radiological evaluation showed an adrenal nodule (15 mm) in the left adrenal gland but an adrenal vein sampling demonstrated a lateralization towards the opposite site favouring the right adrenal to be the source of excess aldosterone. A laparoscopic right adrenalectomy was performed and the histology of the gland confirmed nodular hyperplasia. Following surgery, the patient's BP improved remarkably although he remained on antihypertensives and under regular endocrine follow-up. PA remains the most common form of secondary and difficult-to-treat hypertension. Investigations may reveal incidental adrenal lesions, which may not be the actual source of excess aldosterone, but UAH may be a contributor and may coexist and amenable to surgical treatment. An adrenal vein sampling should be undertaken for correct lateralization of the source, otherwise a correctable diagnosis may be missed and the incorrect adrenal gland may be removed. LEARNING POINTS: Severe and resistant hypertension can often be associated with underlying PA. ARR is an excellent screening tool in patients with suspected PA. Lateralization with adrenal venous sampling is essential to isolate the source and differentiate between unilateral and bilateral causes of hyperaldosteronism. Adrenal incidentalomas and UAH may coexist and the latter may often be the sole cause of excess aldosterone secretion. Decisions about adrenalectomy should be made only after integrating and interpreting radiological and biochemical test findings properly.