Idiopathic Hyperaldosteronism (IHA)

IHA is the most common cause of hyperaldosteronism. The over-growth of the aldosterone producing cells of the adrenal gland is usually diffuse and occurs in both glands equally. IHA causes 70% percent of hyperaldosteronism . The degree of hormone over-production is usually relatively mild. It is important to differentiate hyperaldosteronism due to IHA from hyperaldosteronism due to a discrete tumor (APA). IHA is treated medically, usually with spironolactone, a direct inhibitor of aldosterone. APA is best treated with surgical removal of the adenoma. Separating these two diseases may be challenging. Radiological imaging either with a CT scan or MRI may show an adenoma. If these imaging test are negative then sampling the venous drainage from each adrenal gland for aldosterone may show a higher level on one side suggesting a small adenoma that may be below the resolution of the imaging study. If imaging studies are negative and venous sampling does not show asymmetric secretion, then IHA is likely and surgery is not considered.