Treatment of Hypertension During Investigation of Secondary Causes
During the investigation of secondary hypertension, blood pressure should be controlled with appropriate antihypertensive medications while maintaining a focus on identifying and treating the underlying cause. 1
Initial Approach to Treatment
When secondary hypertension is suspected, a systematic approach is needed:
Maintain BP control during diagnostic workup:
Choice of antihypertensive medications:
Special considerations for medication selection:
- Avoid medications that may interfere with diagnostic testing
- For suspected primary aldosteronism: Consider calcium channel blockers or alpha-blockers initially, as they minimally affect aldosterone testing
- For suspected pheochromocytoma: Alpha-blockers should be initiated before beta-blockers to prevent hypertensive crisis
- For young adults (<40 years): Comprehensive screening for secondary causes is recommended 2
Diagnostic Evaluation While Treating
While maintaining BP control, proceed with appropriate diagnostic testing based on suspected secondary causes:
| 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 |
Medication Adherence Assessment
Before extensive workup for secondary causes, always assess medication adherence 1. Poor adherence is a common cause of apparent treatment resistance and can be mistaken for secondary hypertension.
Lifestyle Modifications
Implement lifestyle modifications alongside pharmacological treatment:
- Weight loss for overweight/obese patients
- DASH diet pattern
- Sodium restriction (<2g/day)
- Regular physical activity (150 minutes/week)
- Alcohol moderation 1, 4
Treatment Adjustments Based on Findings
If secondary cause is identified:
- Target the underlying cause with specific therapy 1
- Continue BP management during treatment of the underlying condition
If no secondary cause is found:
- Optimize antihypertensive therapy
- Consider resistant hypertension management strategies if BP remains uncontrolled on ≥3 medications 1
Follow-up and Monitoring
- Regular BP monitoring (home and office) 1
- Monitor for medication side effects, particularly hyperkalemia and renal function deterioration with ACE inhibitors or ARBs 3
- Periodic assessment of target organ damage 1
Pitfalls and Caveats
Avoid therapeutic inertia: Don't delay appropriate BP control while waiting for diagnostic results 5
Medication interference with testing: Some antihypertensive medications can affect diagnostic test results for secondary hypertension:
- ACE inhibitors and ARBs can affect renin and aldosterone levels
- Beta-blockers can mask symptoms of pheochromocytoma and affect renin levels
- Diuretics can affect electrolyte levels and renin-aldosterone measurements
Medication-induced hypertension: Always review all medications (prescription and over-the-counter) that could contribute to hypertension, including NSAIDs, decongestants, stimulants, oral contraceptives, and certain antidepressants 1
Target organ damage: Assess for evidence of hypertensive damage to heart, kidney, brain, and blood vessels, as this may influence treatment urgency and approach 6
By following this approach, you can effectively manage blood pressure while conducting a thorough investigation for secondary causes of hypertension, ultimately improving patient outcomes through appropriate diagnosis and targeted treatment.