Initial Approach to Treating Myocarditis in Pediatric Patients
Hospital admission is recommended for all suspected cases of pediatric myocarditis to monitor for rapid progression of cardiac involvement, with first-tier immunomodulatory treatment including IVIG at 2 g/kg based on ideal body weight. 1
Diagnostic Evaluation
- Immediate cardiac evaluation is essential, including ECG, echocardiography, and cardiac biomarkers (troponin, BNP/NT-proBNP) 1
- Sequential monitoring of inflammatory markers helps guide treatment decisions and should be established early 1
- Consider evaluating nasal swab and stool for viruses, as well as blood polymerase chain reaction to identify potential viral etiology 1
- Continuous monitoring of ECG, arterial pressure, and tissue perfusion markers should be established in patients with suspected myocarditis 2
Initial Treatment Algorithm
Step 1: Assess Severity and Stabilize
For patients without life-threatening manifestations:
For patients with life-threatening presentation (shock):
Step 2: Immunomodulatory Treatment
- First-line therapy: IVIG at 2 g/kg based on ideal body weight 1
- For patients with shock and/or organ-threatening disease: Add low-to-moderate dose glucocorticoids (1-2 mg/kg/day) as adjunctive therapy with IVIG 1
Step 3: Heart Failure Management
- Implement guideline-directed heart failure therapy including diuretics, beta-blockers, and ACE inhibitors as appropriate 1
- For cardiogenic shock, consider individualized inotropic support with epinephrine, levosimendan, dopamine, or dobutamine 2
- Use dopamine with caution at doses >7 mcg/kg/min as it may increase pulmonary vascular resistance 2
Step 4: Consider Mechanical Support for Severe Cases
- For severe acute heart failure or shock refractory to pharmacological therapy, consider mechanical assist devices and extracorporeal membrane oxygenation (ECMO) as a bridge to recovery or heart transplantation 1, 2
- Early consideration of ECMO is warranted when cardiac index <2.2 L/min/m², cardiac power output <0.6 W, and elevated lactate despite initial therapy 2
Monitoring and Follow-up
- Repeat echocardiograms should be obtained at 7-14 days and then 4-6 weeks after initial presentation 3
- For patients with cardiac involvement during acute illness, consider another echocardiogram at 1 year after diagnosis 3
- Obtain EKGs at minimum every 48 hours during hospitalization and at each follow-up visit to monitor for conduction abnormalities 3
- If conduction abnormalities are present, place patient on telemetry while hospitalized and consider Holter monitoring at follow-up 3
- For patients with moderate-to-severe LV dysfunction, cardiac MRI at 2-6 months post-acute illness allows evaluation of fibrosis and scarring 3
Special Considerations
- In cases of myocarditis associated with multisystem inflammatory syndrome in children (MIS-C), a more aggressive immunomodulatory approach may be needed 1
- Younger children with MIS-C are more likely to present with Kawasaki disease-like features, while older children tend to develop myocarditis and shock 3
- For suspected immune checkpoint inhibitor-associated myocarditis, high-dose corticosteroids (1 mg/kg methylprednisolone IV) should be administered until improvement to grade ≤1, followed by at least 4-5 weeks of tapering 1
Common Pitfalls to Avoid
- Delaying echocardiographic evaluation can lead to missed diagnosis and delayed treatment 2
- Relying solely on blood pressure for assessment without evaluating tissue perfusion markers may lead to inadequate management 2
- Anti-inflammatory therapy with steroids alone (without IVIG) is not beneficial in pediatric myocarditis according to available evidence 1
- Waiting for complete diagnostic results before initiating treatment in patients with life-threatening presentations can lead to worse outcomes 3