Primary hyperaldosteronism due to adrenal microadenoma: a curable cause of refractory hypertension

Abstract

Paper AbstractThe diagnosis of primary hyperaldosteronism due to microadenoma or unilateral adrenal hyperplasia can be challenging, since hypokalaemic alkalosis, high plasma aldosterone and a definite adenoma on imaging may all be absent. Method and result. We describe three cases of resistant hypertension (on > 5 antihypertensives) where hyperaldosteronism was suspected because of a suppressed plasma renin level despite treatment with multiple drugs which normally elevate renin. Renin mass was measured by a double-site chemi-immunoluminometric assay.All patients had normal plasma aldosterone levels. Hypokalaemia was present in the first two cases but computed tomography did not show clear cut adenomas.Adrenal vein sampling (AVS) revealed lateralisation (> 4 times higher aldosterone to cortisol ratio (ACR) on the affected than contra-lateral side).The third patient was normokalaemic and AVS showed only minimal lateralisation (ACR 1.3:1).The severe hypertension in all cases was reversed by adrenalectomy, with blood pressure falling to target despite withdrawal of all but one to two drugs. Conclusions. The robotic assay of renin mass permits rapid detection of patients in whom plasma renin is suppressed below the normal range.A suppressed plasma renin indicates abnormal Na + -retention, and -when not overcome by drugs such as angiotensinconverting enzyme-inhibitors or angiotensin receptor blockers -may be the only clue to a curable adrenal adenoma.AVS is required to demonstrate lateralisation of aldosterone secretion, justifying adrenalectomy.

Difficult-to-control hypertension due to bilateral aldosterone-producing adrenocortical microadenomas associated with a cortisol-producing adrenal macroadenoma

“…36, 37, 38, 39 The diagnosis of microAPA, in our view, should be histopathologically confirmed in two ways; a micronodule should be detected by HE staining, and subsequently immunohistochemically examined for expression of steroidogenic enzymes. 8, 40 The requisite for diagnosis of a microAPA should include increased expression of 3β-HSD and attenuated or negative expression of P450c17 within the lesion, which can be further supported by the presence of ‘paradoxical hyperplasia', that is, suppressed or negative expression of 3β-HSD in the zona glomerulosa of the attached adrenal tissue.…”

Platt versus Pickering: what molecular insight to primary hyperaldosteronism tells us about hypertension

“…Micronodular hyperplasia is often assumed to be bilateral, although unilateral cases are described. 24,25 But on reflection, cases are as likely as not to be unilateral if due to mutational events which occur after the first adrenal stem cell has divided left and right.…”