From the Guidelines
Secondary hypertension workup should begin with a thorough history and physical examination to identify potential causes, followed by initial screening tests including basic metabolic panel, urinalysis, thyroid function tests, and an electrocardiogram, as recommended by the 2020 international society of hypertension global hypertension practice guidelines 1 and the 2024 esc guidelines for the management of elevated blood pressure and hypertension 1.
Key Components of the Workup
- A thorough history and physical examination to identify potential causes of secondary hypertension
- Initial screening tests:
- Basic metabolic panel
- Urinalysis
- Thyroid function tests
- Electrocardiogram
Specialized Testing Based on Clinical Suspicion
- For suspected renovascular hypertension: renal ultrasound with Doppler or CT angiography
- For primary aldosteronism: measure aldosterone-to-renin ratio after discontinuing interfering medications (like ACE inhibitors, ARBs, and diuretics) for 2-4 weeks
- For pheochromocytoma: 24-hour urine metanephrines or plasma free metanephrines
- For Cushing's syndrome: overnight dexamethasone suppression test or 24-hour urinary free cortisol
- For sleep apnea: screening should be considered in patients with obesity, snoring, or daytime somnolence
- For drug-induced hypertension: detailed medication review, including prescription drugs, over-the-counter medications, and substances like alcohol, cocaine, and herbal supplements
- For coarctation of the aorta: chest X-ray and echocardiogram
Importance of Sequential Testing
These tests should be ordered sequentially based on clinical suspicion rather than all at once, as secondary hypertension causes are relatively uncommon but important to identify since treating the underlying cause can potentially cure the hypertension or significantly improve blood pressure control, as emphasized by the 2017 acc/aha/aapa/abc/acpm/ags/apha/ash/aspc/nma/pcna guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.
From the Research
Evaluation of Secondary Hypertension
The evaluation of secondary hypertension involves a comprehensive approach to identify the underlying cause of hypertension. According to 2, the initial workup aims to establish the presence of sustained hypertension, identify curable causes, and assess target organ damage. The evaluation includes:
- A complete general medical evaluation
- Special measures to characterize the disease
- Identification of attendant risk factors such as smoking, alcohol use, and obesity
- Characterization of the hypertension in terms of its pathophysiology
- Assessment of target organ damage to the heart, brain, and kidneys
Diagnostic Approach
The diagnostic approach to secondary hypertension involves a combination of clinical evaluation, laboratory tests, and imaging studies. As noted in 3, features that aid in the diagnosis of secondary hypertension include:
- Onset of hypertension before the age of 20 or after the age of 50 years
- Markedly elevated blood pressure or hypertension with severe end-organ damage
- Specific body habitus and ancillary physical findings
- Resistant or refractory hypertension
- Specific biochemical tests that suggest the existence of certain disorders
Common Causes of Secondary Hypertension
Common causes of secondary hypertension include:
- Renal parenchymal disease
- Renovascular diseases
- Coarctation of the aorta
- Cushing's syndrome
- Primary hyperaldosteronism
- Pheochromocytoma
- Hyperthyroidism
- Hyperparathyroidism As discussed in 4 and 5, these causes can be identified through a combination of clinical evaluation, laboratory tests, and imaging studies.
Screening and Treatment
Screening for secondary hypertension is warranted in patients with specific characteristics, such as resistant hypertension or severe end-organ damage. According to 6, treatment is specific to the underlying cause and includes medications, procedures, surgery, and device therapies. The goal of treatment is to control blood pressure and prevent target organ damage.