What is the treatment for pericarditis and myopericarditis, particularly in cases with elevated troponin levels indicating myocardial involvement?

Treatment of Pericarditis and Myopericarditis

The treatment of myopericarditis should follow similar guidelines as pericarditis, with NSAIDs as first-line therapy, but potentially at reduced dosages compared to pure pericarditis due to myocardial involvement, along with mandatory physical activity restriction for 6 months. 1

Understanding the Difference Between Pericarditis and Myopericarditis

Myopericarditis is distinguished from pericarditis by the presence of myocardial involvement, which is indicated by:

• Elevated cardiac biomarkers (troponin I or T, CK-MB fraction)
• Clinical signs of pericarditis (pericardial rubs, ST-segment elevation, pericardial effusion)
• Preserved left ventricular function (if LV function is impaired, it's considered "perimyocarditis") 1

Treatment Algorithm for Pericarditis

First-Line Therapy:

• NSAIDs at high doses:
  • Aspirin 1500-3000 mg/day (especially if ischemic heart disease is present)
  • Ibuprofen 1200-2400 mg/day
  • Indomethacin 75-150 mg/day 1
• Colchicine as adjunctive therapy:
  • 0.5 mg twice daily (or 0.5 mg daily for patients <70 kg)
  • Continue for 3 months for first episode
  • Continue for at least 6 months for recurrent cases 1, 2

Second-Line Therapy:

• Corticosteroids when NSAIDs are contraindicated, not tolerated, or ineffective
  • Prednisone 0.2-0.5 mg/kg/day 3
  • Taper slowly after symptom resolution and CRP normalization 1

Special Considerations for Myopericarditis

1. Anti-inflammatory therapy:

   • Similar to pericarditis but some experts recommend reduced NSAID dosages 1
   • Caution with NSAIDs as animal models suggest they may enhance inflammation in myocarditis, though human evidence is limited 1

2. Physical activity restrictions:

   • Mandatory rest and avoidance of physical activity beyond normal sedentary activities for 6 months 1
   • More restrictive than for isolated pericarditis (which allows return to activity after symptom resolution) 1
   • This is critical as sudden cardiac death cases have been reported in athletes and military personnel after strenuous exertion 1

3. Hospitalization:

   • Recommended for all patients with myopericardial involvement for diagnosis and monitoring 1
   • Essential to rule out acute coronary syndromes with coronary angiography when appropriate 1

4. Diagnostic evaluation:

   • Cardiac magnetic resonance is recommended to confirm myocardial involvement 1
   • Serial CRP measurements to guide treatment duration 1

Prognosis

Myopericarditis generally has a good prognosis with:

• No evolution to heart failure in most cases 1
• Low mortality rates 4
• Recurrences occurring in approximately 13% of cases, mainly as recurrent pericarditis 4
• Cardiac tamponade and constrictive pericarditis occurring in less than 1% of cases 4

Common Pitfalls and Caveats

1. Avoid corticosteroids as first-line therapy:

   • Associated with higher recurrence rates 1, 2
   • Use only when NSAIDs and colchicine fail or are contraindicated

2. Don't underestimate the importance of activity restriction:

   • Premature return to physical activity can lead to complications including sudden cardiac death 1

3. Don't discontinue therapy too early:

   • Continue until complete symptom resolution and CRP normalization 1
   • Taper medications gradually to prevent recurrence

4. Don't miss underlying etiologies:

   • While most cases in developed countries are idiopathic or viral, consider tuberculosis in endemic areas 2
   • Rule out systemic autoimmune diseases and malignancies in appropriate clinical contexts

5. Avoid NSAIDs in patients with renal dysfunction:

   • Consider corticosteroids as primary therapy when NSAIDs are contraindicated 3

By following these evidence-based guidelines, most patients with pericarditis and myopericarditis can be effectively managed with good outcomes and minimal complications.