What are the causes of Conns syndrome?
Conn’s syndrome, or primary hyperaldosteronism, is the most common cause of secondary hypertension, and is caused by a hyperfunctional adrenal adenoma in 65% of cases and by bilateral adrenal hyperplasia in 35% of cases. Hyperfunctional ACC and unilateral adrenal hyperplasia are rare causes of Conn’s syndrome. Patients typically have an elevated serum aldosterone level, a low serum renin level, and a low serum potassium level. This is in contradistinction to patients who have secondary hyperaldosteronism (such as in the setting of renal artery stenosis) where there is instead physiologic activation of the renin-angiotensin-aldosterone axis.
In patients with Conn’s syndrome, it is important to differentiate between unilateral versus bilateral adrenal pathologies as the underlying etiology. This is because an adrenal adenoma or unilateral adrenal hyperplasia may be treated with laparoscopic resection of the adrenal gland, whereas bilateral adrenal hyperplasia is usually managed medically. Adrenal vein sampling is also commonly performed to determine whether autonomous aldosterone production from the adrenal glands is unilateral or bilateral, as there is often discordance with cross-sectional imaging findings, particularly when the adrenal glands appear normal or when multiple bilateral adrenal gland nodules are present.