Treatment of Acute Pericarditis Post-MI
For acute pericarditis following myocardial infarction, initiate acetaminophen for symptomatic relief in early cases (1-3 days post-MI), and if symptoms persist or for late pericarditis (Dressler's syndrome), escalate to high-dose aspirin (500-1,000 mg every 6-8 hours) combined with colchicine (0.5-0.6 mg once or twice daily for 3 months). 1
Initial Conservative Management
Early post-MI pericarditis (occurring 1-3 days after transmural MI) is typically transient and inflammatory in nature due to adjacent myocardial necrosis. 1
- Start with acetaminophen for symptomatic relief as first-line therapy for early pericarditis 1
- These cases usually resolve within several days with conservative therapy alone 1
- Monitor for symptom resolution and avoid unnecessary escalation if improving 1
Escalation to Anti-Inflammatory Therapy
If symptoms persist despite acetaminophen or for late pericarditis (Dressler's syndrome) occurring weeks after MI, escalate treatment:
High-Dose Aspirin
- Dose: 500-1,000 mg every 6-8 hours until symptoms improve 1, 2
- This anti-inflammatory dose is substantially higher than antiplatelet dosing (81-325 mg daily) 2
- Aspirin is the only NSAID that should be used post-MI 1, 2
- Provide gastroprotection with this regimen 2, 3
Add Colchicine
- Dose: 0.5-0.6 mg once daily if <70 kg, or twice daily if ≥70 kg 1, 2
- Duration: 3 months to reduce recurrence risk 1, 2
- Further dose adjustment required for stage 4-5 kidney disease, severe hepatic impairment, or with P-glycoprotein/CYP3A4 inhibitors 1
- Colchicine reduces recurrence rates from 30% to 15% 2
Diagnostic Criteria
Diagnosis requires pleuritic chest pain PLUS at least one of the following: 1
- Pericardial friction rub on auscultation (pathognomonic finding) 1, 4
- ECG changes: PR-segment depression, diffuse concave ST-elevations, or persistent ST-elevations/dynamic T-wave changes in MI setting 1
- New or growing pericardial effusion on echocardiography 1
Critical Pitfalls to Avoid
Absolutely Contraindicated Medications
Never use non-aspirin NSAIDs (ibuprofen, indomethacin, etc.) in post-MI pericarditis as they:
- Impair myocardial healing 1, 2
- Increase risk of ventricular rupture 1, 2
- Increase mortality and reinfarction risk 4
Avoid glucocorticoids due to:
- Increased risk of recurrent MI 1, 2
- Impaired myocardial healing and rupture risk 1, 2
- Should only be considered as second-line if NSAIDs/colchicine fail or are contraindicated, and only after excluding infection 2, 3
Common Dosing Errors
- Do not use low-dose "antiplatelet" aspirin (81-325 mg) for pericarditis—this dose is ineffective for inflammation 2
- Do not treat asymptomatic pericardial effusions with high-dose aspirin or colchicine routinely 1
- Pericardial effusions occur in up to 28-43% of post-MI patients but most are small and resolve spontaneously 5, 6, 7
Monitoring and Duration
- Guide treatment duration by symptom resolution and CRP normalization 2, 3
- Taper aspirin gradually (by 250-500 mg every 1-2 weeks) only when symptoms absent and CRP normalized 2, 3
- Continue colchicine for full 3-month course regardless of symptom resolution 1, 2
- Exercise restriction until symptoms resolve and CRP, ECG, and echocardiogram normalize 3
Distinguishing Early vs. Late Pericarditis
Early pericarditis (1-3 days post-MI):
- Due to inflammatory response to myocardial necrosis 1
- Typically transient, lasting several days 1
- Often responds to acetaminophen alone 1
Late pericarditis/Dressler's syndrome (weeks to months post-MI):
- Immune-mediated response to pericardial irritation 1
- Incidence now 0.1-0.5% in era of early reperfusion 1
- Requires more aggressive therapy with high-dose aspirin and colchicine 1
- May present with fever, malaise, and larger effusions 5
When to Consider Cardiac Tamponade
Cardiac tamponade is extremely rare in post-MI pericarditis absent cardiac rupture 6