What diagnostic tests are indicated for a 24-year-old patient newly diagnosed with hypertension?

Diagnostic Testing for a 24-Year-Old with Hypertension

A 24-year-old with newly diagnosed hypertension requires both routine baseline testing and heightened screening for secondary causes, given that age <30 years is a major red flag for underlying pathology.

Mandatory Baseline Laboratory Tests

All young hypertensive patients require a comprehensive initial workup to assess cardiovascular risk, detect target-organ damage, and screen for secondary causes:

• Serum creatinine and estimated glomerular filtration rate (eGFR) to evaluate kidney function and detect chronic kidney disease 1
• Serum electrolytes (sodium and potassium) – spontaneous or diuretic-induced hypokalemia strongly suggests primary aldosteronism 1, 2
• Urinalysis with urine albumin-to-creatinine ratio (not dipstick alone) to detect early kidney damage and cardiovascular risk 1, 3
• Fasting blood glucose or HbA1c to identify diabetes mellitus, which significantly increases cardiovascular risk 1, 3
• Fasting lipid profile (total cholesterol, LDL, HDL, triglycerides) for cardiovascular risk stratification 1, 3
• Thyroid-stimulating hormone (TSH) to screen for hypothyroidism and hyperthyroidism, both remediable causes of hypertension 1, 2, 3
• Complete blood count (hemoglobin/hematocrit) to detect anemia or other hematologic abnormalities 1, 3
• 12-lead electrocardiogram to detect left ventricular hypertrophy, arrhythmias (including atrial fibrillation), and ischemic heart disease 1, 3

Screening for Secondary Hypertension (Critical in Young Adults)

The 2024 ESC guidelines now recommend measuring plasma aldosterone-to-renin ratio in ALL adults with confirmed hypertension (Class IIa recommendation), representing a major paradigm shift from selective screening. 1, 2, 4 This is particularly important in a 24-year-old, where secondary causes account for a much higher proportion than in older adults.

Key Clinical Red Flags Already Present

• Age <30 years is itself a major red flag for secondary hypertension, especially fibromuscular dysplasia, coarctation, or endocrine disorders 2, 4, 5, 6
• Young patients warrant heightened suspicion for secondary causes given the absence of typical risk factors like gradual onset with family history 3

Additional Physical Examination Maneuvers

• Measure thigh blood pressure – if lower than arm pressures, consider coarctation of the aorta 3
• Assess for radio-femoral delay – suggests coarctation 1, 2
• Auscultate for abdominal bruits – indicates renovascular disease 1, 2
• Measure neck circumference – >40 cm suggests obstructive sleep apnea 1, 2
• Examine for Cushing features – central obesity, wide purple striae, easy bruising, proximal muscle weakness, moon facies, buffalo hump 2

Optional Advanced Testing (Based on Clinical Suspicion or Resources)

• Echocardiography should be performed if ECG shows abnormalities, cardiac symptoms are present, or in all newly diagnosed hypertensive patients if resources allow, as it detects left ventricular hypertrophy and diastolic dysfunction that predict cardiovascular events even in young adults 1, 3
• Renal ultrasound with Doppler if renovascular disease is suspected based on clinical features 1, 4
• 24-hour ambulatory blood pressure monitoring to exclude white-coat hypertension (occurs in 20-30% of apparent hypertension) and detect non-dipping patterns suggestive of secondary causes 2, 5

Confirmatory Testing When Screening is Positive

If the aldosterone-to-renin ratio is elevated (>20 with elevated aldosterone and suppressed renin):

• Intravenous saline suppression test or oral sodium-loading test for biochemical confirmation of primary aldosteronism 2, 4
• Adrenal CT imaging for lesion localization after positive biochemical testing 2, 4
• Adrenal vein sampling when surgical intervention is contemplated 2, 4

Critical Pitfalls to Avoid

• Do not skip the aldosterone-to-renin ratio – the 2024 ESC guidelines now recommend this for all confirmed hypertension, and primary aldosteronism accounts for 8-20% of resistant hypertension 1, 2
• Use urine albumin-to-creatinine ratio, not dipstick alone – it is more sensitive for detecting early kidney damage 3
• Review all medications and substances – NSAIDs, decongestants, oral contraceptives, stimulants can cause hypertension and must be excluded before extensive workup 2, 4
• Do not overlook coarctation of the aorta – measure thigh blood pressure in all patients ≤30 years with elevated brachial pressure 3
• Confirm hypertension with repeated measurements before extensive workup, but do not delay basic laboratory testing once hypertension is confirmed 3

When to Refer to a Specialist

Refer to a hypertension specialist or endocrinologist when:

• Screening tests are positive and require confirmatory evaluation 2
• Complex procedures such as adrenal vein sampling are needed 2
• Surgical intervention is being considered (e.g., unilateral adrenalectomy for primary aldosteronism) 2
• Blood pressure remains uncontrolled after ≥6 months of optimal medical therapy 2