Hypertension is the Characteristic Feature of Primary Hyperaldosteronism
The correct answer is (c) hypertension, which is the most common and characteristic feature of primary hyperaldosteronism.
Pathophysiology of Primary Hyperaldosteronism
Primary hyperaldosteronism (also called primary aldosteronism) is characterized by:
- Excessive and autonomous production of aldosterone by the adrenal glands, independent of the renin-angiotensin system 1, 2
- Hypertension, which is present in virtually all patients and is often resistant to conventional treatment 1
- Suppressed plasma renin activity (hypo-reninism, not hyper-reninism) due to negative feedback from excess aldosterone 1, 2
- Sodium retention and increased potassium excretion 1, 3
Why Hypertension is the Correct Answer
Hypertension is the hallmark clinical manifestation of primary hyperaldosteronism for several reasons:
- Recent studies indicate that primary aldosteronism is present in approximately 5-10% of all hypertensive patients, with prevalence increasing to 13% among patients with severe hypertension (180/110 mmHg) 1
- Among patients with resistant hypertension, the prevalence of primary aldosteronism is even higher at approximately 20% 1
- Hypertension occurs due to excessive aldosterone causing increased sodium and water retention, leading to expanded plasma volume and increased peripheral vascular resistance 2, 4
Why the Other Options are Incorrect
(a) Hyperkalemia: Primary hyperaldosteronism typically causes hypokalemia (low potassium), not hyperkalemia, due to increased urinary potassium excretion driven by excess aldosterone. However, hypokalemia is a late manifestation and is absent in the majority of cases 1, 5
(b) Hyper-reninism: Primary hyperaldosteronism causes hypo-reninism (suppressed renin), not hyper-reninism. The excessive autonomous aldosterone production suppresses renin release through negative feedback 1, 2
(d) Hyperplasia of zona reticularis: The zona reticularis produces androgens, not aldosterone. Primary hyperaldosteronism involves the zona glomerulosa, which is the site of aldosterone production 2
(e) Hyperplasia of zona fasciculata: The zona fasciculata produces cortisol, not aldosterone. In primary hyperaldosteronism, the pathology involves the zona glomerulosa 2
Clinical Implications
- Screening for primary hyperaldosteronism is recommended in patients with resistant hypertension, hypokalemia, adrenal incidentaloma, family history of early-onset hypertension, or stroke at a young age 1, 5
- The aldosterone-to-renin ratio is the recommended screening test, with a common cutoff value of 30 when plasma aldosterone concentration is reported in ng/dL and plasma renin activity in ng/mL/h 1, 2
- Compared to primary hypertension, primary aldosteronism causes more end-organ damage and is associated with excess cardiovascular morbidity, including heart failure, stroke, myocardial infarction, and atrial fibrillation 1, 6
Treatment Approach
- Unilateral laparoscopic adrenalectomy is the treatment of choice for unilateral disease (usually aldosterone-producing adenoma), which improves blood pressure in nearly 100% of patients and achieves complete cure of hypertension in approximately 50% 1, 4
- Medical therapy with mineralocorticoid receptor antagonists (MRAs), particularly spironolactone, is the cornerstone of treatment for bilateral disease (idiopathic hyperaldosteronism) 4
- Spironolactone dosing for primary hyperaldosteronism typically ranges from 100 mg to 400 mg daily 4
Understanding that hypertension is the characteristic feature of primary hyperaldosteronism is crucial for proper clinical recognition and management of this common but often underdiagnosed cause of secondary hypertension.