What is the recommended diagnostic workup for a 2-year-old patient with hypertension?

Diagnostic Workup for a 2-Year-Old with Hypertension

For a 2-year-old with confirmed hypertension, perform a comprehensive laboratory and imaging evaluation to identify secondary causes, as over 85% of hypertensive children this young have an identifiable underlying etiology, most commonly renal parenchymal disease. 1

Initial Blood Pressure Confirmation

• Confirm hypertension with proper technique: Use oscillometric devices for BP measurement in toddlers who cannot cooperate with auscultatory readings, following standardized cuff sizing and positioning 2
• Obtain multiple BP readings at the same visit—discard the first oscillometric reading and average subsequent readings 2
• Repeat BP measurements at 1-2 week intervals to confirm persistent elevation before proceeding with extensive workup 2
• Categorize BP severity using age-specific normative data for infants and toddlers from the Second Task Force report 2

Mandatory Laboratory Studies

The following laboratory tests must be obtained to evaluate for secondary causes of hypertension in this age group: 2

• Serum chemistries: Including electrolytes (sodium, potassium, chloride, bicarbonate), blood urea nitrogen, and creatinine with estimated glomerular filtration rate 2
• Complete blood count: To evaluate for anemia or other hematologic abnormalities 3
• Urinalysis: Screen for blood, protein, and signs of kidney disease 2
• Urinary albumin-to-creatinine ratio: More sensitive than dipstick for detecting early kidney damage 3

Essential Imaging Studies

• Renal ultrasonography is mandatory: All children under 3 years with confirmed hypertension require renal ultrasound to evaluate for renal parenchymal disease, discrepant kidney sizes, or structural abnormalities 1
• Assess for kidney size discrepancy, hydronephrosis, cystic disease, or other structural abnormalities that suggest renovascular disease 2

History and Physical Examination Focus

Target your evaluation toward identifying specific secondary causes common in this age group: 2

Critical Historical Elements:

• Perinatal history: Prematurity, very low birth weight, or neonatal complications requiring intensive care 2
• Congenital conditions: History of congenital heart disease (repaired or unrepaired), particularly coarctation of the aorta 2
• Renal history: Recurrent urinary tract infections, hematuria, known renal disease, or urologic malformations 2
• Family history: Congenital renal disease or early-onset hypertension 2
• Medication exposure: Drugs known to raise BP 2
• Systemic conditions: Neurofibromatosis, tuberous sclerosis, or other conditions associated with hypertension 2

Physical Examination Priorities:

• Four-limb blood pressures: Essential to detect coarctation of the aorta 4
• Cardiovascular examination: Assess for heart murmurs, radio-femoral pulse delay, or differential upper/lower extremity pulses suggesting coarctation 2
• Abdominal examination: Palpate for masses, listen for renal bruits (though rare in toddlers) 2
• Fundoscopic examination: Evaluate for retinal changes, hemorrhages, or papilledema indicating hypertensive target organ damage 2

Additional Diagnostic Testing Based on Severity

For Stage 1 Hypertension (95th-99th percentile + 5 mmHg):

• Proceed with basic workup as outlined above 2
• Consider echocardiography if hypertension persists to assess for left ventricular hypertrophy 2

For Stage 2 Hypertension (≥99th percentile + 5 mmHg):

• Immediate referral to pediatric hypertension specialist within 1 week OR begin treatment while initiating workup 2
• Echocardiography is strongly recommended: Assess left ventricular mass and cardiac function, as this is the best method for detecting hypertensive target organ damage 2
• Consider advanced imaging: If renal ultrasound suggests renovascular disease (discrepant kidney sizes, abnormal Doppler flow), proceed to magnetic resonance angiography or computed tomography angiography 1

Specific Secondary Causes to Evaluate in This Age Group

Renal parenchymal disease is the most common cause in children under 3 years: 1

• Congenital anomalies of the kidney and urinary tract
• Polycystic kidney disease
• Reflux nephropathy
• Obstructive uropathy

Renovascular disease considerations: 2

• Suspect if stage 2 hypertension, significant diastolic elevation, discrepant kidney sizes on ultrasound, or hypokalemia on screening labs 2

Cardiovascular causes: 2

• Coarctation of the aorta (detected by four-limb BP and differential pulses)
• Congenital heart disease

Endocrine causes (less common in this age): 2

• Consider if hypokalemia, suppressed plasma renin, or family history of early-onset hypertension suggests monogenic forms 2

Common Pitfalls to Avoid

• Do not rely on single BP measurement: Multiple readings over multiple visits are essential to confirm true hypertension and avoid overdiagnosis 2
• Do not use wrist or forearm BP measurements: These are unreliable for diagnosis in children 2
• Do not skip renal ultrasound: This is mandatory in all hypertensive children under 3 years given the high prevalence of renal causes 1
• Do not delay specialist referral for stage 2 hypertension: These children require urgent evaluation within 1 week 2
• Do not use urine dipstick alone: Quantitative urinary albumin-to-creatinine ratio is more sensitive for detecting kidney damage 3

Follow-Up Strategy

• If workup reveals secondary cause, treat the underlying condition 2
• If stage 1 hypertension confirmed without identifiable cause, repeat BP in 1-2 weeks and consider lifestyle modifications (though limited in a 2-year-old) 2
• Follow-up every 3-6 months for patients managed with observation or lifestyle modification only 2
• If antihypertensive medication initiated, follow-up every 4-6 weeks until BP controlled 2