What are the diagnostic criteria and treatment options for pericarditis?

Diagnosis and Treatment of Pericarditis

The diagnosis of pericarditis requires at least 2 of 4 key criteria: pericarditic chest pain, pericardial friction rub, new widespread ST-elevation or PR depression on ECG, and pericardial effusion (new or worsening). 1, 2

Diagnostic Criteria

Primary Diagnostic Criteria

• Pericarditic chest pain: Sharp, retrosternal, pleuritic chest pain that typically worsens with inspiration and improves with sitting forward (present in ~90% of cases) 2, 3, 4
• Pericardial friction rub: Highly specific but transient auscultatory finding (present in 18-84% of cases), best heard with the patient sitting upright and leaning forward while briefly holding their breath 2, 3, 5
• ECG changes: New widespread ST-segment elevation (concave upward) or PR depression in multiple leads (present in 25-60% of cases) 1, 2, 5
• Pericardial effusion: New or worsening fluid collection around the heart detected by imaging (present in ~60% of cases) 1, 2, 4

Supporting Diagnostic Tests

• Inflammatory markers: Elevated C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count 1, 2, 6
• Cardiac biomarkers: Should be assessed to evaluate for myocardial involvement (myopericarditis) 2, 6
• Imaging studies:
  • Transthoracic echocardiography: Recommended in all patients with suspected pericarditis 2, 5
  • Chest X-ray: Often normal unless pericardial effusion exceeds 300 ml 2
  • Cardiac MRI: Useful for distinguishing myopericarditis from other causes 3

Risk Stratification

High-Risk Features (Requiring Hospitalization)

• Fever >38°C (>100.4°F) 2, 7
• Subacute onset 2, 7
• Large pericardial effusion or cardiac tamponade 2, 7
• Failure to respond to NSAIDs within 7 days 2, 7
• Elevated cardiac biomarkers (indicating myopericardial involvement) 2, 3

Low-Risk Features (Outpatient Management)

• Absence of high-risk features 2
• Good response to initial anti-inflammatory therapy 2

Treatment Algorithm

First-Line Treatment

• NSAIDs: Mainstay of therapy for idiopathic and viral pericarditis 2, 4, 5
  • Continue at high doses until pain resolves and CRP normalizes, then taper over several weeks 4
• Colchicine: Should be added to NSAIDs to improve response and reduce recurrence rates (from ~37.5% to 16.7%) 2, 4, 8
  • For first episode: 3-month course 4
  • For recurrent episodes: At least 6-month course 4

Second-Line Treatment

• Corticosteroids: Reserved for patients with:
  • Contraindications to NSAIDs and colchicine 2, 5
  • Pregnancy beyond 20 weeks' gestation 5
  • Systemic inflammatory conditions 5
  • Failure to respond to first-line therapy 4, 9

Refractory/Recurrent Pericarditis

• IL-1 blockers: Demonstrated efficacy for multiple recurrences and may be preferred to long-term corticosteroids 4

Etiological Considerations

Common Causes

• Idiopathic/viral: 80-90% of cases in developed countries 4, 9
• Post-cardiac injury syndromes: Following cardiac procedures or operations 4
• Tuberculosis: Leading cause in endemic areas 4, 9
• Autoimmune: Systemic lupus erythematosus, rheumatoid arthritis, etc. 1, 6
• Neoplastic: Primary tumors (rare) or secondary metastatic tumors 1

Common Pitfalls and Caveats

• ECG changes may be absent in up to 40% of cases 2
• Pericardial friction rubs are transient and may require multiple examinations 3, 5
• Normal inflammatory markers do not exclude pericarditis, especially if the patient is already on anti-inflammatory treatment 2, 6
• Cardiac biomarker elevation may indicate concomitant myocarditis rather than primary pericardial disease 2, 6
• A normal echocardiogram does not exclude the diagnosis of pericarditis 3