What is the treatment approach for secondary hypertension?

Treatment Approach for Secondary Hypertension

The treatment of secondary hypertension must focus on identifying and addressing the underlying cause while maintaining blood pressure control to reduce morbidity and mortality. 1

Identification of Secondary Hypertension

Secondary hypertension accounts for 5-10% of all hypertension cases and requires specific clinical clues for detection:

Clinical Red Flags

• Abrupt onset of hypertension
• Hypertension onset before age 30
• Accelerated/malignant hypertension
• Sudden loss of BP control in previously controlled patients
• Use of BP-raising substances (NSAIDs, amphetamines, immunosuppressants)
• Resistant or refractory hypertension
• Unprovoked/excessive hypokalemia
• Onset of diastolic hypertension in older patients (≥65 years) 2

Diagnostic Workup

For suspected secondary hypertension, the following tests are recommended:

Suspected Cause	Recommended Screening Test
Primary aldosteronism	Aldosterone-to-renin ratio
Renovascular hypertension	Renal Doppler ultrasound, CT/MR angiography
Pheochromocytoma	24h urinary/plasma metanephrines and normetanephrines
Obstructive sleep apnea	Overnight polysomnography
Renal parenchymal disease	Renal ultrasound, urinalysis, eGFR
Cushing's syndrome	24h urinary free cortisol, dexamethasone suppression
Thyroid disease	TSH
Hyperparathyroidism	PTH, calcium, phosphate
Coarctation of aorta	Echocardiogram, CT angiogram

Treatment Strategies

1. Obstructive Sleep Apnea

• CPAP therapy for moderate to severe cases
• Weight loss program
• Continue antihypertensive medications as needed 1
• Sleep apnea is commonly encountered in resistant and refractory hypertension 2

2. Primary Aldosteronism

• Unilateral disease: Adrenalectomy is treatment of choice
• Bilateral disease (~60% of cases): Mineralocorticoid receptor antagonists (spironolactone, eplerenone) 2, 1
• Primary aldosteronism prevalence is approximately 20% in patients with resistant hypertension 2

3. Renovascular Hypertension

• Medical therapy is recommended for most patients with atherosclerotic renal artery stenosis
• Consider revascularization only in select cases with critical stenosis and specific clinical presentations 2, 1
• Medication regimen should include RAS blockers (ACE inhibitors or ARBs) unless contraindicated 1

4. Pheochromocytoma

• Surgical removal after adequate alpha-blockade
• Critical: Alpha-blockers must be initiated before beta-blockers to prevent hypertensive crisis 1

5. Medication-Induced Hypertension

• Discontinue or modify offending medications when possible
• Common culprits: NSAIDs, oral contraceptives, steroids, immunosuppressants 2, 1

Pharmacological Management During Workup

While investigating the underlying cause, blood pressure control remains essential:

• First-line agents include:

  • RAS blockers (ACE inhibitors like lisinopril or ARBs)
  • Dihydropyridine calcium channel blockers
  • Thiazide/thiazide-like diuretics 1, 3

• For resistant hypertension:

  • Add low-dose spironolactone (25 mg daily)
  • If intolerant to spironolactone, consider eplerenone, amiloride, higher dose diuretics, or addition of bisoprolol/doxazosin 1

Important Considerations

• Medication adherence should always be assessed before extensive workup for secondary causes 1
• Continue antihypertensive therapy during the diagnostic workup 1
• Regular BP monitoring (both home and office) is essential for management 1
• Even after treating the underlying cause, residual hypertension often persists due to vascular remodeling or concomitant essential hypertension 4
• For truly resistant cases, referral to specialized hypertension centers should be considered 1

Pitfalls to Avoid

• Delayed diagnosis: Secondary hypertension is often underrecognized, leading to preventable target organ damage 5
• Premature beta-blockade in suspected pheochromocytoma can precipitate hypertensive crisis 1
• Overlooking medication-induced causes: Always review all medications, including over-the-counter drugs 2
• Assuming complete cure: Despite treating the underlying cause, many patients will still require antihypertensive medications long-term 4

Remember that early detection and treatment of secondary hypertension are crucial to minimize irreversible vascular changes and reduce morbidity and mortality from hypertension-related complications.