What is the recommended diagnostic workup and management for primary hyperaldosteronism?

Primary Hyperaldosteronism: Diagnostic Workup and Management

Screen all hypertensive patients who have resistant hypertension, hypokalemia, adrenal incidentaloma, family history of early-onset hypertension, or stroke before age 40 using the plasma aldosterone-to-renin activity ratio, then proceed with confirmatory testing and adrenal venous sampling to guide definitive treatment with either unilateral laparoscopic adrenalectomy for unilateral disease or mineralocorticoid receptor antagonists for bilateral disease. 1

Who to Screen

Target screening to high-risk hypertensive patients to reduce cardiovascular morbidity and mortality, as primary aldosteronism causes disproportionate cardiovascular and kidney damage compared to essential hypertension 1:

• Resistant hypertension (uncontrolled BP on 3+ medications) 1
• Spontaneous or substantial diuretic-induced hypokalemia 1
• Adrenal incidentaloma discovered on imaging 1
• Family history of early-onset hypertension or stroke at young age (<40 years) 1

Critical caveat: Hypokalemia is absent in the majority of primary aldosteronism cases and has low negative predictive value, so do not rely on its presence for screening decisions 1.

Screening Test

Use the plasma aldosterone-to-renin activity ratio (ARR) as the initial screening test 1:

• Cutoff value: ARR >30 (when aldosterone in ng/dL and renin activity in ng/mL/h) 1
• Plasma aldosterone must be ≥10 ng/dL to interpret positive result, as very low renin levels can falsely elevate the ratio 1

Pre-test Preparation Requirements

Optimize testing conditions to avoid false results 1:

• Withdraw mineralocorticoid receptor antagonists (spironolactone, eplerenone) for at least 4 weeks before testing 1
• Ensure unrestricted salt intake 1
• Normalize serum potassium before testing 1

Confirmatory Testing

Perform confirmatory testing after positive screening to reduce false-positives 1:

• Intravenous saline suppression test 1
• Oral salt-loading test 1

Specialist Referral

Refer all patients with positive screening tests to a hypertension specialist or endocrinologist for further evaluation and treatment 1. This ensures appropriate confirmatory testing, subtype differentiation, and treatment planning 1.

Subtype Differentiation

Adrenal Venous Sampling

Perform adrenal venous sampling (AVS) in confirmed primary aldosteronism patients who are surgical candidates to distinguish unilateral from bilateral disease 1, 2:

• AVS is the gold standard for lateralization, as CT/MRI imaging alone is unreliable 3, 4
• Exception: May reasonably omit AVS in patients <40 years with imaging showing only one affected gland, as bilateral hyperplasia is rare in this population 3
• Be aware that AVS carries risk of adrenal hemorrhage 5

Imaging

Obtain CT or MRI to assess adrenal anatomy 1:

• Helps identify adenomas vs hyperplasia 1
• Suspect malignancy if: irregular morphology, lipid-poor appearance, poor contrast washout, size >3 cm, or multi-hormone secretion 3

Treatment Algorithm

Unilateral Disease (Adenoma or Unilateral Hyperplasia)

Perform unilateral laparoscopic adrenalectomy for unilateral aldosterone production 1, 2:

• Improves BP in virtually 100% of patients 1
• Cures hypertension in approximately 50% 1
• Reverses left ventricular hypertrophy and reduces cardiovascular complications 1
• Minimally invasive surgery should be performed when feasible 2
• For suspected malignancy: perform open adrenalectomy due to rupture risk 3

Bilateral Disease or Non-surgical Candidates

Treat with mineralocorticoid receptor antagonists as first-line therapy 1:

Spironolactone (Preferred Agent)

• Dose: 50-100 mg once daily, titrate up to 300-400 mg daily if needed 6, 7
• Most widely available and cost-effective 7
• Monitor and titrate to unsuppress renin for optimal cardiovascular protection 5, 7
• Side effects: gynaecomastia and erectile dysfunction in men 6

Eplerenone (Alternative)

• Less potent than spironolactone, requires twice-daily dosing 6
• Advantage: fewer androgen/progesterone receptor-mediated side effects (less gynaecomastia, erectile dysfunction) 6, 7
• Consider when spironolactone not tolerated 6, 7

Monitoring Treatment Efficacy

In patients on MRA therapy with uncontrolled hypertension, monitor renin levels and titrate MRA dose to increase renin into the normal range 7. Suppressed renin despite MRA therapy is associated with higher mortality, atrial fibrillation, and stroke risk 5, 7.

Special Considerations

Familial Hyperaldosteronism Type 1 (Glucocorticoid-Remediable)

Treat with low-dose dexamethasone in patients with family history of early-onset hypertension/stroke and confirmed genetic diagnosis 1, 6:

• Can be safely used during pregnancy 6
• Use doses low enough to avoid glucocorticoid side effects 6

Autonomous Cortisol Co-secretion

Perform 1-mg overnight dexamethasone suppression test in all patients with PA and adrenal adenoma to screen for concurrent autonomous cortisol secretion 2.

Key Pitfalls to Avoid

• Do not dismiss primary aldosteronism based on normal potassium levels – most patients are normokalemic 1
• Do not rely on imaging alone for lateralization – proceed with AVS in surgical candidates 3, 4
• Do not continue mineralocorticoid receptor antagonists during screening – withdraw for 4 weeks minimum 1
• Do not accept suppressed renin as adequate treatment response – titrate MRA to normalize renin for cardiovascular protection 5, 7