What are the characteristic clinical findings associated with aldosteronoma?

Aldosteronoma Clinical Features

Aldosteronoma is associated with hypertension, hypokalemia, high aldosterone and low renin levels (option d). 1, 2, 3

Pathophysiology of Aldosteronoma

• Aldosteronoma (aldosterone-producing adenoma) is characterized by excessive and autonomous production of aldosterone by the adrenal glands, independent of the renin-angiotensin system 1
• This excessive aldosterone production leads to:
  • Sodium retention and volume expansion 1
  • Suppression of plasma renin activity 1, 3
  • Increased potassium excretion, which can cause hypokalemia if prolonged and severe 1, 3
• Approximately 50% of patients with primary aldosteronism have unilateral increased aldosterone production, usually due to an aldosterone-producing adenoma 1

Key Clinical Features

• Hypertension: Patients with aldosteronoma typically present with moderate to marked hypertension that is often resistant to treatment 4, 3
• Hypokalemia: A classic finding in aldosteronoma, though it may be absent in up to 50% of cases, especially in early stages 4, 1, 5
• High aldosterone levels: Elevated plasma and/or urinary aldosterone is a hallmark of aldosteronoma 1, 5
• Low renin levels: Plasma renin activity is suppressed due to the autonomous production of aldosterone 1, 2, 3

Diagnostic Approach

• The aldosterone-to-renin ratio (ARR) is the most accurate and reliable screening test for aldosteronoma 4, 2
• A positive ARR is defined as:
  • Ratio >30 (when aldosterone is measured in ng/dL and renin activity in ng/mL/h) 2
  • Plasma aldosterone concentration should be at least 10 ng/dL 2
• Confirmatory testing is required after a positive screening test to demonstrate autonomous aldosterone production 2
• Adrenal imaging (CT or MRI) and adrenal venous sampling help differentiate between unilateral adenoma and bilateral hyperplasia 4, 2

Clinical Impact and Complications

• Aldosteronoma causes greater target organ damage than primary hypertension, including: 4, 3
  • 3.7-fold increase in heart failure
  • 4.2-fold increase in stroke
  • 6.5-fold increase in myocardial infarction
  • 12.1-fold increase in atrial fibrillation
• Increased left ventricular hypertrophy and diastolic dysfunction 4
• Increased stiffness of large arteries and widespread tissue fibrosis 4
• Increased remodeling of resistance vessels and kidney damage 4

Common Pitfalls in Diagnosis

• Relying solely on hypokalemia as a marker, as it is absent in many cases 2, 5
• Not screening high-risk patients with resistant hypertension 2
• Failing to consider medication effects on the aldosterone-renin ratio 2
• Proceeding with adrenalectomy based on imaging alone without adrenal venous sampling 4, 2

Treatment

• Unilateral laparoscopic adrenalectomy is the treatment of choice for aldosteronoma 1, 2
• Surgery improves blood pressure in nearly 100% of patients and achieves complete cure of hypertension in approximately 50% of cases 1, 2
• Medical therapy with mineralocorticoid receptor antagonists (spironolactone or eplerenone) is an alternative when surgery is not possible 1, 2