Hyperaldosteronism Causes and Clinical Implications

Primary Aldosteronism

The American College of Cardiology notes that primary aldosteronism accounts for 5-10% of all hypertensive patients and is the most common endocrine cause of hypertension, characterized by autonomous aldosterone production from the adrenal glands 1
Primary aldosteronism results from aldosterone production that is independent of the renin-angiotensin system and cannot be suppressed with sodium loading, according to the European Society of Cardiology 2
Aldosterone-producing adenoma (APA) is the most frequent unilateral cause of primary aldosteronism, typically presenting as a solitary benign tumor that autonomously secretes aldosterone, as stated by the American Heart Association 1, 2
Unilateral adrenal hyperplasia is a rare cause of unilateral primary aldosteronism 2
Bilateral adrenal hyperplasia (idiopathic hyperaldosteronism) accounts for 50% of primary aldosteronism cases, as reported by the European Society of Endocrinology 2

The European Heart Journal states that secondary hyperaldosteronism occurs when aldosterone production is appropriately elevated in response to activation of the renin-angiotensin system, often due to renovascular hypertension, renal parenchymal disease, heart failure, or cirrhosis with ascites 3
Renovascular hypertension from renal artery stenosis stimulates renin release, leading to secondary hyperaldosteronism, according to the American College of Cardiology 3
Diuretics, ACE inhibitors, ARBs, and beta-blockers can increase renin and aldosterone levels, or alter the aldosterone-to-renin ratio, as noted by the European Society of Cardiology 3

The key to differentiating primary from secondary hyperaldosteronism is measuring both aldosterone and renin, with primary aldosteronism showing elevated aldosterone with suppressed renin (high aldosterone-to-renin ratio >30), as stated by the American Heart Association 4, 2
Primary aldosteronism causes increased heart failure, stroke, MI, and atrial fibrillation compared to primary hypertension matched for blood pressure, emphasizing the importance of identifying the underlying cause, as reported by the American College of Cardiology 5, 1
Hypokalemia is absent in 50% of primary aldosteronism cases, and should not be relied upon to suspect hyperaldosteronism, according to the European Society of Endocrinology 4, 1

The European Society of Cardiology recommends considering secondary hyperaldosteronism when both renin and aldosterone are elevated together with hypertension, as this pattern is more consistent with renovascular hypertension or renal parenchymal disease 6, 7
The American Heart Association suggests that a low Aldosterone-to-Renin Ratio (ARR) effectively rules out primary aldosteronism as the cause, with a threshold of 20-30 7, 8
The American College of Cardiology recommends screening for renovascular hypertension using renal Duplex Doppler ultrasound as the initial test, followed by MRA or CT angiography if positive or if there is high clinical suspicion 6, 7, 8

The European Society of Cardiology recommends assessing renal function by measuring serum creatinine, eGFR, electrolytes, urinalysis with microscopy, and urinary albumin-to-creatinine ratio 6, 7, 8
Renal ultrasound should be performed to assess for structural abnormalities, obstruction, or polycystic kidney disease 6, 7, 8
The American Heart Association suggests considering the effects of medications, such as diuretics and ACE inhibitors/ARBs, on the renin-angiotensin-aldosterone system and withdrawing them when feasible before definitive testing 6, 7

The American College of Cardiology warns against assuming primary aldosteronism based on elevated aldosterone alone, as the suppressed renin is the defining feature of primary aldosteronism 8
The European Society of Cardiology cautions against overlooking renovascular disease, as it is the most common cause of secondary hyperaldosteronism with this laboratory pattern and is potentially curable with revascularization in fibromuscular dysplasia 6, 7