What is the initial management of secondary hypertension?

Initial Management of Secondary Hypertension

The initial management of secondary hypertension requires treating the underlying cause while maintaining blood pressure control with appropriate pharmacotherapy. 1

Diagnostic Approach

Before initiating treatment, identifying the underlying cause is essential:

1. Comprehensive evaluation for suspected causes:

   • Use targeted screening tests based on clinical presentation:
     • 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 1

2. Clinical clues suggesting secondary hypertension:

   • Severe or resistant hypertension
   • Age of onset younger than 30 years
   • Malignant or accelerated hypertension
   • Acute rise in blood pressure from previously stable readings 2

Treatment Algorithm

Step 1: Blood Pressure Control

While investigating the underlying cause, initiate BP control if severely elevated:

• For moderate-severe hypertension:

  • Start with RAS blockers (ACE inhibitors like lisinopril or ARBs) as first-line therapy 1
  • Initial dose of lisinopril: 10 mg once daily, adjusting to 20-40 mg per day based on response 3
  • Add dihydropyridine calcium channel blockers or thiazide/thiazide-like diuretics if needed 1
  • If using diuretics with lisinopril, start with 5 mg once daily 3

• For resistant hypertension:

  • Consider adding spironolactone 25 mg daily (if eGFR >50 mL/min/1.73m² and serum potassium ≤5.0 mEq/L) 1, 4
  • For spironolactone intolerance, consider eplerenone, amiloride, higher-dose thiazide diuretics, or addition of beta-blockers like metoprolol 1, 5

Step 2: Cause-Specific Management

• Primary aldosteronism:

  • Spironolactone 25-100 mg daily is the cornerstone of medical therapy 4, 6
  • Consider surgical referral for unilateral adenomas

• Renovascular hypertension:

  • Medical therapy with ACE inhibitors or ARBs (monitor for acute kidney injury)
  • Consider revascularization for fibromuscular dysplasia or severe atherosclerotic disease 1

• Pheochromocytoma:

  • Alpha-blockade before beta-blockade (to avoid hypertensive crisis)
  • Surgical referral once stabilized 1

• Obstructive sleep apnea:

  • CPAP therapy alongside antihypertensive medications
  • Weight loss and lifestyle modifications 1, 7

• Renal parenchymal disease:

  • ACE inhibitors or ARBs (with careful monitoring of renal function)
  • Treat underlying kidney disease 1

• Drug-induced hypertension:

  • Discontinue or modify offending medications when possible 7

Lifestyle Modifications

Implement these essential adjunctive measures for all patients:

• Weight loss for overweight/obese patients
• Sodium restriction (<2.3g/day)
• Regular physical activity (150 min/week moderate-intensity)
• DASH diet pattern
• Alcohol moderation (≤2 drinks/day for men, ≤1 drink/day for women) 1

Follow-up and Monitoring

• Regular BP monitoring (home and office)
• Monitor for medication side effects, particularly hyperkalemia and renal function deterioration with ACE inhibitors, ARBs, and spironolactone
• Periodic assessment of target organ damage
• If CKD is present, repeat measurements of serum creatinine, eGFR, and urine ACR at least annually 1

Important Considerations and Pitfalls

• Medication adherence: Always assess before extensive workup for secondary causes 1

• Screening timing: For new or untreated hypertension, consider screening before starting medications that affect the renin-angiotensin-aldosterone system 6

• Avoid delay: Secondary hypertension is present in approximately 10% of hypertensive adults and early recognition enables timely diagnosis and more effective management 8

• Specialist referral: Consider for complex cases or when specialized expertise is needed for treating the underlying condition 8

• ACE inhibitor caution: Monitor for acute increase in serum creatinine (>50% within one week of initiating therapy), which may suggest renovascular hypertension 2