What is the treatment for influenza pericarditis?

Treatment of Influenza Pericarditis

The treatment of influenza pericarditis primarily consists of NSAIDs as first-line therapy, with the addition of colchicine for prevention of recurrences, while corticosteroids should be avoided due to risk of viral reactivation. 1

Diagnosis and Assessment

Before initiating treatment, confirm the diagnosis through:

• ECG (look for widespread ST-segment elevation and PR depression)
• Echocardiography (to assess for pericardial effusion)
• Laboratory tests (inflammatory markers like CRP, CBC, cardiac biomarkers)
• PCR testing for influenza virus (from respiratory specimens and, when possible, pericardial fluid)

Treatment Algorithm

First-Line Treatment

1. NSAIDs/Aspirin:

   • High-dose regimen until symptom resolution and normalization of inflammatory markers
   • Examples: Ibuprofen 600-800mg every 8 hours or Aspirin 750-1000mg every 8 hours

2. Colchicine (add to NSAIDs):

   • 0.5-1.0mg twice daily for 3-6 months
   • Reduces recurrence rates from 15-30% to 8-15%
   • Adjust dose for patients <70kg (0.5mg once daily)

3. Antiviral Therapy:

   • Oseltamivir should be administered when influenza is confirmed
   • Standard dosing: 75mg twice daily for 5 days
   • Start as early as possible in the disease course 2, 3

Management of Complications

1. For Hemodynamic Compromise:

   • Pericardiocentesis is indicated for cardiac tamponade or large effusions (>20mm)
   • Monitor for signs of tamponade: hypotension, tachycardia, pulsus paradoxus, distant heart sounds 2

2. For Persistent Symptoms:

   • Continue NSAIDs and colchicine until complete resolution of symptoms and normalization of inflammatory markers
   • Extend treatment duration if symptoms persist

What to Avoid

1. Corticosteroids:
   • NOT recommended in viral pericarditis (Class III recommendation)
   • Can reactivate viral infections and lead to ongoing inflammation 1

Special Considerations

• Activity Restriction: Limit physical activity beyond ordinary sedentary life until symptoms resolve and CRP normalizes (minimum 3 months for athletes)
• Monitoring: Regular follow-up with echocardiography and CRP levels to assess treatment response
• Recurrence: If symptoms recur, restart first-line therapy at full doses

Evidence Quality and Caveats

The European Society of Cardiology (ESC) guidelines provide the strongest evidence for management of viral pericarditis, including influenza. While specific studies on influenza pericarditis are limited, case reports demonstrate that standard viral pericarditis treatment protocols are effective 1.

Case reports highlight that influenza pericarditis can range from mild to life-threatening with potential for cardiac tamponade, which occurs in approximately 36% of cases 4. Influenza A appears to be more commonly associated with pericarditis than influenza B, but both can cause significant disease 4.

The mortality rate for influenza myopericarditis has been reported at 14.7%, with cardiogenic shock being more common in patients with myocardial involvement (64%) 4. Therefore, early recognition and appropriate management are critical.

Key Points to Remember

• Influenza pericarditis is an inflammatory condition that typically responds well to NSAIDs and colchicine
• Antiviral therapy with oseltamivir should be included when influenza is confirmed
• Avoid corticosteroids due to risk of viral reactivation
• Monitor closely for complications such as cardiac tamponade, which requires immediate intervention
• Continue treatment until complete symptom resolution and normalization of inflammatory markers