“Up to 28% of patients may be defined as having resistant hypertension (not controlled on three drugs or controlled on four or more drugs). Primary aldosteronism is present in up to 5%–10% of all hypertensive patients and 7%–20% of those with resistant hypertension. This may be due to bilateral adrenal hyperplasia or a unilateral aldosterone-secreting adenoma, which can be diagnosed if there is elevated serum aldosterone in the presence of suppressed renin levels. A cortisol level and a dexamethasone suppression test are appropriate tests for Cushing syndrome. A
17-hydroxyprogesterone level tests for congenital adrenal hyperplasia. Renal ultrasonography will not adequately screen for any of these conditions.
“Hyperaldosteronism, usually caused by a hyperaldosterone-secreting adrenal mass, has to be considered in a middle-aged patient with resistant hypertension and hypokalemia. Peripheral aldosterone concentration (PAC) and peripheral renin activity (PRA), preferably after being upright for 2 hours, are the preferred screening tests for hyperaldosteronism. A PAC >15 ng/dL and a PAC/PRA ratio >20 suggest an adrenal cause. Abdominal CT may miss adrenal hyperplasia or a microadenoma. Renal CT angiography is useful for detecting renal artery stenosis. If the PAC/PRA is abnormal, an aldosterone suppression test should be ordered.” ABFM
References
Primary aldosteronism: Diagnosis and management. Am J Med Sci 2016;352(4):391-398.
Am Fam Physician 2010;82(12):1471-1478.
JAMA 2014;311(21):2216-2224.