What is the role of corticosteroids (e.g. prednisone) in myocarditis?

Corticosteroids in Myocarditis

Primary Recommendation

Corticosteroids are NOT recommended for routine treatment of acute viral myocarditis and should generally be avoided unless specific high-risk features or non-viral etiologies are present. 1, 2

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When to AVOID Corticosteroids

Viral Myocarditis (Most Common)

• Do not use corticosteroids in typical viral myocarditis - they do not reduce mortality (RR 0.93,95% CI 0.70-1.24) and can reactivate viral infections, perpetuating inflammation rather than resolving it 1, 2
• The European Society of Cardiology gives a Class III (harm) recommendation against corticosteroids in viral pericarditis/myocarditis due to risk of viral reactivation 1
• NSAIDs and corticosteroids may actually increase inflammation and mortality in isolated myocarditis without pericardial involvement 3, 1

Myopericarditis (Pericarditis-Predominant)

• When myocardial involvement is minor (elevated troponins but preserved LV function), treat as pericarditis with aspirin (1500-3000 mg/day) or NSAIDs (ibuprofen 1200-2400 mg/day) as first-line 3
• Corticosteroids are second-line only after contraindication, intolerance, or failure of aspirin/NSAIDs 3
• If corticosteroids must be used in myopericarditis, reduce dosages compared to pure pericarditis (start 0.25-0.50 mg/kg/day prednisone) 3

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When to CONSIDER Corticosteroids

Specific High-Risk Scenarios

1. COVID-19 Myocarditis with Pneumonia

• Use corticosteroids if patient has both myocarditis AND COVID-19 pneumonia requiring supplemental oxygen 3

2. Hemodynamic Compromise or Fulminant Myocarditis

• Intravenous corticosteroids may be considered in suspected/confirmed COVID-19 myocarditis with hemodynamic instability or multisystem inflammatory syndrome in adults (MIS-A) 3
• Empiric corticosteroids may be considered with biopsy evidence of severe myocardial infiltrates or fulminant presentation, balanced against infection risk 3, 1

3. Immune Checkpoint Inhibitor Myocarditis

• Emergent high-dose corticosteroids (1 mg/kg methylprednisolone IV) should be initiated immediately in suspected or confirmed cases 1, 4
• This is a medical emergency with approximately 20% mortality risk 4
• Continue for several days until improved to grade ≤1, then taper over at least 4-5 weeks 4

4. Non-Viral Myocarditis Etiologies

• Giant cell myocarditis: Immunosuppression indicated 1, 5
• Cardiac sarcoidosis: Immunosuppression indicated 1, 5
• Eosinophilic myocarditis: Corticosteroids are standard treatment 1, 5, 6
• Systemic autoimmune disorders (e.g., lupus): Immunosuppression appropriate 5

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Recommended Treatment Approach Instead

Standard Management for Viral Myocarditis

• Guideline-directed medical therapy for heart failure: ACE inhibitors/ARBs, beta-blockers (if hemodynamically stable), aldosterone antagonists 1
• Supportive care with hemodynamic monitoring and arrhythmia management 1
• Activity restriction for 3-6 months - sustained aerobic exercise during acute viral myocarditis increases mortality and sudden death risk 3, 1
• Mechanical circulatory support if cardiogenic shock develops despite optimal medical management 1

Diagnostic Workup Required

• Cardiac troponin (troponin I preferred over T when skeletal muscle disease present) 4
• ECG to detect conduction abnormalities, ST-T changes 4
• Echocardiogram for wall motion abnormalities, LV function 3
• Cardiac MRI recommended in hemodynamically stable patients with suspected myocarditis for definitive diagnosis 3
• Consider endomyocardial biopsy if diagnosis unclear or to guide immunosuppression decisions 3

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Critical Pitfalls to Avoid

FDA Warning on Post-MI Use

• Literature reports suggest association between corticosteroids and left ventricular free wall rupture after recent myocardial infarction - use with great caution in these patients 7

Infection Risk

• Corticosteroids suppress immune system and increase risk of infection with any pathogen (viral, bacterial, fungal, protozoan, helminthic) 7
• Can reduce resistance to new infections, exacerbate existing infections, increase disseminated infection risk, and mask signs of infection 7
• Monitor for tuberculosis reactivation in latent TB patients 7

Distinguishing Myopericarditis from Perimyocarditis

• Myopericarditis (pericarditis-predominant): Elevated troponins WITHOUT new LV dysfunction - treat as pericarditis 3
• Perimyocarditis (myocarditis-predominant): Elevated troponins WITH new focal/diffuse LV dysfunction - avoid corticosteroids unless specific indications 3

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Prognosis Considerations

• Myopericarditis (pericarditis-predominant) has excellent prognosis with no evolution to heart failure or mortality in observational series 3
• Uncomplicated myocarditis has approximately 0% mortality in hospitalized patients 5
• Myocarditis with acute heart failure or ventricular arrhythmias has 12% in-hospital mortality or transplant rate 5
• Fulminant myocarditis with hemodynamic instability has 28% mortality or transplant rate at 60 days 5