Diagnosis and management of primary aldosteronism

Identifying primary aldosteronism within the hypertensive population is an important clinical challenge, as most patients with a unilateral source of excess aldosterone secretion are amenable to surgical cure. At least 20% of patients with primary aldosteronism have normal serum potassium levels. Therefore, screening tests should not be based on recognition of hypokalemia alone. Rather, the diagnosis should depend on identifying renin suppression and measuring the ratio of plasma ahlosterone concentration to plasma renin activity. The diagnosis may be confirmed by performing an aldosterone suppression test after oral salt loading. Once primary aldosteronism has been established, it is necessary to exclude glucocorticoid-remediable aldosteronism and then proceed to localization studies. Detecting a unilateral source of aldosterone, usually due to an adenoma (Conn syndrome), is achieved by postural hormonal testing and confirmed by selective venous sampling (SVS) with measurement of aldosterone concentrations (expressed as the aldosterone/cortisol ratio) in each adrenal vein. SVS is enjoying a revival in many institutions as it is more sensitive and specific than either cross-sectional imaging or scintigraphy and has the potential to influence significantly both the diagnosis and clinical decision-making. Patients with unilateral disease are ideally treated by laparoscopic adrenalectomy. Patients in whom localization is not achieved usually have bilateral adrenal hyperplasia and are treated medically.