What is the management approach for a newborn with elevated troponins (cardiac biomarker)?

Management of Elevated Troponins in Newborns

In newborns with elevated troponin levels, a systematic diagnostic approach should be implemented with cardiac monitoring, focused echocardiography, and ECG evaluation, as the most common causes in this population are myocarditis, perimyocarditis, and hypoxic-ischemic events rather than coronary artery disease.

Causes of Elevated Troponins in Newborns

Unlike adults where troponin elevation typically indicates coronary artery disease, troponin elevation in newborns has different etiologies:

• Cardiac causes:

  • Myocarditis/perimyocarditis 1
  • Congenital heart defects (e.g., ALCAPA) 2
  • Cardiomyopathy 3

• Non-cardiac causes:

  • Hypoxic-ischemic encephalopathy (HIE) 4
  • Sepsis
  • Respiratory distress/hypoxemia
  • Drug toxicity 1

Diagnostic Approach

1. Initial assessment:

   • Evaluate vital signs with particular attention to tachycardia, which was present in all patients with elevated troponins in pediatric COVID-19 studies 5
   • Assess for signs of respiratory distress, cyanosis, or poor perfusion
   • Check for hepatomegaly or other signs of heart failure

2. Essential diagnostic tests:

   • ECG - Look for ST-segment changes, T-wave abnormalities, arrhythmias 6, 2
   • Chest X-ray - Assess for cardiomegaly, pulmonary edema 2
   • Echocardiography - Evaluate cardiac function, structure, wall motion abnormalities 2
   • Serial troponin measurements - Establish rising/falling pattern 7

3. Additional testing based on clinical suspicion:

   • Cardiac MRI - Particularly valuable for suspected myocarditis 6
   • Right heart catheterization - May be useful in selected cases 2
   • Viral studies - If myocarditis is suspected

Important Distinctions from Adult Management

• Avoid routine coronary angiography - Left heart catheterization rarely changes diagnosis in pediatric patients with elevated troponins 2
• Do not apply adult "door-to-balloon time" protocols - These are not appropriate for newborns 2

Management Strategy

1. Monitoring:

   • Continuous cardiac monitoring with telemetry 7
   • Regular vital sign assessment
   • Serial troponin measurements to establish trend

2. Supportive care:

   • Ensure adequate oxygenation
   • Maintain hemodynamic stability
   • Treat underlying causes (e.g., antibiotics for sepsis)

3. Specific management based on etiology:

   • For myocarditis: Anti-inflammatory therapy, heart failure management
   • For HIE: Consider therapeutic hypothermia if indicated 4
   • For structural heart disease: Cardiology consultation for surgical planning

Prognostic Considerations

• Troponin levels ≥180 pg/mL in HIE have been associated with hypotension during admission and abnormal neurodevelopmental outcomes at 1 year 4
• Persistent troponin elevation suggests ongoing cardiac damage 7
• Higher troponin levels correlate with increased risk of adverse outcomes 7

Pitfalls to Avoid

• Don't assume coronary artery disease - Unlike adults, this is rare in newborns 2
• Don't rush to cardiac catheterization - This should be reserved for specific indications 2
• Don't ignore non-cardiac causes - Elevated troponins can result from systemic conditions 7, 1
• Don't miss rare but serious conditions - Such as infantile restrictive cardiomyopathy which may present with elevated troponins 3

By following this structured approach, clinicians can appropriately evaluate and manage newborns with elevated troponin levels, focusing on the most likely etiologies in this age group.