Diagnosis of primary aldosteronism in a patient with an incidentally found adrenal mass.

BACKGROUND: A 50-year-old woman who was complaining of abdominal pain was referred to the endocrine clinic after a small (0.8 cm by 0.8 cm) mass was found in her right adrenal gland on CT examination of the abdomen. She had a history of hypertension for 10 years, generalized anxiety disorder for 5 years and a weight increase of 18 kg over the previous 3 years. The patient did not report weakness, polyuria or excessive thirst. She had a history of hypokalemia while on hydrochlorothiazide therapy. To improve blood pressure control, a total of three antihypertensive medications had been sequentially added to her regimen. At presentation, medications included 300 mg irbesartan daily, 5 mg amlodipine daily and 100 mg sustained-release metoprolol daily.

INVESTIGATIONS: Renin activity, levels of plasma aldosterone and levels of fractionated plasma metanephrines were measured and an overnight 1 mg dexamethasone suppression test was performed. In addition, measurements of urine aldosterone excretion on a high-salt diet, MRI-examination of the adrenal glands and bilateral adrenal vein sampling were conducted.

DIAGNOSIS: An aldosterone-secreting adrenal adenoma.

MANAGEMENT: The patient underwent laparoscopic resection of the right adrenal gland, which led to normalization of aldosterone excretion, lowering of her blood pressure on a single antihypertensive medication (50 mg sustained-release metoprolol daily) and resolution of hypokalemia.