Diagnostic Criteria for Pericarditis
Acute pericarditis is diagnosed when at least 2 of the following 4 criteria are present: pericarditic chest pain, pericardial friction rub, new widespread ST-elevation or PR depression on ECG, and new or worsening pericardial effusion. 1
Core Diagnostic Criteria (≥2 Required)
The European Society of Cardiology establishes that diagnosis requires meeting at least 2 of these 4 cardinal features: 1, 2
Pericarditic chest pain: Sharp, pleuritic, retrosternal pain that worsens with inspiration and improves when sitting forward or leaning forward; present in approximately 90% of cases 2, 3
Pericardial friction rub: Auscultatory finding representing friction between inflamed pericardial layers, heard best at the left lower sternal border; highly specific but transient, reported in 18-84% of cases (often <30% in practice) 2, 4, 3
ECG changes: New widespread ST-segment elevation (with upward concavity) or PR depression in multiple leads; present in only 25-60% of cases 1, 2, 3
Pericardial effusion: New or worsening fluid collection detected by imaging; present in approximately 60% of cases 1, 2, 3
Additional Supporting Findings
While not required for diagnosis, these findings strengthen the clinical picture: 1
Elevated inflammatory markers: C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count are commonly elevated and useful for monitoring disease activity and treatment response 1, 2, 5
Advanced imaging: CT or cardiac MRI can provide additional evidence of pericardial inflammation 1
Cardiac biomarkers: Troponin and creatine kinase (CK) may be elevated, indicating concomitant myocardial involvement (myopericarditis) rather than isolated pericarditis 1, 5
Recommended Diagnostic Workup
All patients with suspected pericarditis should undergo: 1
- ECG (Class I recommendation) 1
- Transthoracic echocardiography (Class I recommendation) 1, 2
- Chest X-ray (Class I recommendation), though typically normal unless effusion exceeds 300 mL 1, 2
- Assessment of inflammatory markers (CRP) and myocardial injury markers (troponin, CK) (Class I recommendation) 1, 5
Important Clinical Caveats
ECG changes may be absent in up to 40% of cases, so their absence does not exclude pericarditis if other criteria are met. 2, 5 The ECG reflects epicardial inflammation since the parietal pericardium itself is electrically inert. 1
Pericardial friction rubs are highly specific but often transient, disappearing within hours to days, so a single negative examination does not rule out pericarditis. 4
Normal inflammatory markers do not exclude pericarditis, particularly if the patient is already receiving anti-inflammatory treatment when tested. 2, 5
Elevated cardiac biomarkers indicate myopericarditis (concomitant myocardial involvement) rather than isolated pericardial disease and may warrant closer monitoring. 1, 2
The major differential diagnosis is acute coronary syndrome with ST-segment elevation, which must be carefully excluded given the overlapping ECG findings. 1 ST elevations in pericarditis are typically widespread with upward concavity, lack reciprocal changes, and are accompanied by PR depressions. 1, 4