Neonatal Hypertension

Key Points

• Underrecognized condition affecting 0.2-3% of neonates
• Higher prevalence in NICU populations (up to 3%)
• Requires careful blood pressure measurement techniques
• Often secondary to underlying conditions
• Early recognition crucial for preventing end-organ damage

Introduction

Neonatal hypertension represents a significant challenge in both diagnosis and management. Understanding normal blood pressure values and their variations with gestational age, postnatal age, and birth weight is crucial for accurate diagnosis and appropriate intervention.

Definition and Epidemiology

Blood Pressure Norms

• Term Infants
  • Systolic BP: 65-95 mmHg
  • Diastolic BP: 30-60 mmHg
  • Mean arterial pressure: 45-65 mmHg
• Preterm Infants
  • Values vary by gestational age
  • Generally lower than term infants
  • Increases with postnatal age

Diagnostic Criteria

• BP > 95th percentile for:
  • Gestational age
  • Postnatal age
  • Birth weight
• Requires multiple measurements
• Confirmation in all four extremities

Etiology and Risk Factors

Renovascular Causes (40-45%)

• Renal Artery Thrombosis
  • Umbilical artery catheterization
  • Inherited thrombophilia
• Renal Artery Stenosis
• Renal Vein Thrombosis
• Congenital Renal Anomalies

Cardiac Causes (10-15%)

• Coarctation of Aorta
• Aortic Stenosis
• Patent Ductus Arteriosus

Pulmonary Causes (5-10%)

• Bronchopulmonary Dysplasia
• Pneumothorax

Endocrine Causes (5-10%)

• Congenital Adrenal Hyperplasia
• Hyperthyroidism
• Pseudohypoaldosteronism

Iatrogenic Causes (20-25%)

• Medications
  • Dexamethasone
  • Caffeine
  • Vasopressors
• Fluid Overload
• Pain/Agitation

Clinical Features

Common Presentations

• Asymptomatic (most common)
• Cardiovascular
  • Tachycardia
  • Heart failure
  • Poor perfusion
• Neurological
  • Irritability
  • Lethargy
  • Seizures
• Respiratory
  • Tachypnea
  • Respiratory distress

Physical Examination

• Blood Pressure Measurement
  • All four extremities
  • Appropriate cuff size
  • Multiple readings
• Systemic Examination
  • Growth parameters
  • Dysmorphic features
  • End-organ damage signs

Diagnostic Approach

Initial Evaluation

• Laboratory Studies
  • Complete blood count
  • Renal function tests
  • Electrolytes
  • Blood gas analysis
• Endocrine Evaluation
  • Plasma renin activity
  • Aldosterone levels
  • Thyroid function tests
  • 17-OH progesterone

Imaging Studies

• First-Line
  • Renal ultrasonography with Doppler
  • Echocardiogram
  • Chest X-ray
• Advanced Imaging
  • MRA/CTA of renal vessels
  • Nuclear medicine studies
  • Angiography when indicated

Management Strategy

General Principles

• Treat Underlying Cause
• Monitor End-organ Function
• Gradual BP Reduction
• Regular Monitoring

Pharmacological Treatment

• First-Line Agents
  • Calcium channel blockers
    • Nicardipine
    • Amlodipine
  • ACE inhibitors
    • Captopril
    • Enalapril
• Emergency Treatment
  • Hydralazine
  • Labetalol
  • Sodium nitroprusside

Non-Pharmacological Measures

• Fluid Management
• Salt Restriction
• Pain Management
• Environmental Modification

Complications and Follow-up

Potential Complications

• Cardiovascular
  • Heart failure
  • Cardiomegaly
• Neurological
  • Intracranial hemorrhage
  • Seizures
  • Developmental delay
• Renal
  • Chronic kidney disease
  • Proteinuria

Follow-up Care

• Regular BP Monitoring
• Growth Assessment
• Developmental Screening
• Medication Adjustment
• Long-term Organ Function Monitoring

Prognosis

• Dependent on underlying cause
• Better with early recognition
• May require long-term follow-up
• Risk of recurrence