How to diagnose and manage acute pericarditis in a patient presenting with chest pain that worsens when lying supine?

Diagnosis and Management of Acute Pericarditis

Diagnose acute pericarditis when at least 2 of 4 clinical criteria are present: characteristic pleuritic chest pain worsening when supine, pericardial friction rub, new widespread ST-elevation or PR depression on ECG, or new/worsening pericardial effusion. 1

Diagnostic Approach

Clinical Presentation

• Sharp, pleuritic chest pain that worsens with inspiration, coughing, and lying supine, improving when sitting up or leaning forward occurs in approximately 90% of cases 1, 2, 3
• Pain is typically retrosternal and may radiate to the trapezius ridge, neck, or back 4, 5
• The positional nature of the pain (worse supine, better leaning forward) is the hallmark distinguishing feature from acute coronary syndrome 2

Mandatory Initial Testing

Perform these tests immediately in all patients with suspected pericarditis:

• ECG within 10 minutes to identify diffuse concave upward ST-segment elevation and PR-segment depression (present in 25-60% of cases) 1, 4
• Transthoracic echocardiography to detect pericardial effusion (present in ~60% of cases) and evaluate for tamponade 1, 6
• Chest X-ray to assess for cardiomegaly (suggests large effusion >300mL) and rule out other intrathoracic causes 1, 4
• Inflammatory markers (CRP, ESR, white blood cell count) to confirm inflammation and monitor treatment response 1
• Cardiac biomarkers (troponin, CK) as troponin elevation occurs in up to 50% of cases, indicating myopericarditis 1, 4, 6

Physical Examination

• Pericardial friction rub is highly specific but only audible in 18-33% of patients 1, 6, 3
• Listen with the patient sitting upright, leaning forward, during brief breath-hold at the left lower sternal border 4
• The rub can be mono-, bi-, or triphasic and is often transient, requiring repeated examinations 4

Advanced Imaging When Indicated

• Cardiac MRI has 94-100% sensitivity for detecting pericardial inflammation and is useful when diagnostic uncertainty exists or myopericarditis is suspected 1, 4
• CMR can distinguish between acute myopericarditis, other cardiomyopathies, and myocardial infarction 1
• Cardiac CT is a reasonable second-line study showing pericardial thickening or enhancement with 54-59% sensitivity and 91-96% specificity 1

Risk Stratification

High-Risk Features Requiring Hospitalization

Admit patients with any of the following 1:

• High fever >38°C (>100.4°F)
• Subacute course (symptoms developing over several days)
• Large pericardial effusion (diastolic echo-free space >20mm)
• Cardiac tamponade
• Failure to respond to NSAIDs within 7 days
• Elevated troponin indicating myopericarditis
• Immunosuppressed state
• Trauma or anticoagulation therapy

Low-Risk Patients

Patients without high-risk features can be managed as outpatients with empiric anti-inflammatory therapy and follow-up within 1 week to assess treatment response 1

Management

First-Line Treatment

NSAIDs are the cornerstone of therapy: 1, 6, 3

• Ibuprofen 600-800mg three times daily for 1-2 weeks, then taper over several weeks once chest pain resolves and CRP normalizes 1, 3
• Alternative: Aspirin or indomethacin at equivalent anti-inflammatory doses 3, 7

Colchicine must be added to reduce recurrence risk: 1, 6, 3

• Colchicine 0.6mg twice daily for 3 months reduces recurrence from 37.5% to 16.7% (absolute risk reduction 20.8%) 3
• This combination therapy is superior to NSAIDs alone and should be standard practice 6, 7

Second-Line Treatment

Corticosteroids should be reserved for specific situations: 1, 6, 3

• Use only when contraindications to NSAIDs exist, pregnancy beyond 20 weeks, or other systemic inflammatory conditions are present 6
• Avoid as first-line therapy as they increase recurrence risk 7
• Consider for patients failing NSAIDs and colchicine combination 3, 7

Recurrent Pericarditis

• First recurrence: Continue colchicine for at least 6 months (not just 3 months) 3
• Multiple recurrences: Consider IL-1 blockers (anakinra) as steroid-sparing therapy for patients dependent on corticosteroids 3, 7
• Surgical pericardiectomy is reserved for patients refractory to all medical therapy 7

Follow-Up and Monitoring

• Reassess at 1 week to evaluate response to anti-inflammatory therapy 1
• Monitor CRP levels to guide treatment duration and tapering 1
• Continue NSAIDs until chest pain resolves and CRP normalizes, typically over several weeks 3
• Recurrence occurs in 15-30% of patients, most commonly within 18-24 months 3, 7

Critical Pitfalls to Avoid

• Do not use nitroglycerin response as a diagnostic test - it relieves esophageal spasm and other non-cardiac conditions 2
• Do not delay transfer for troponin testing in the office if high-risk features are present; send immediately to emergency department by EMS 2
• Do not dismiss the diagnosis based on absent friction rub - it is only present in less than one-third of confirmed cases 4, 6
• Do not use corticosteroids as first-line therapy - they increase recurrence risk and should be reserved for specific indications 6, 7
• Normal echocardiogram does not exclude pericarditis - effusion is only present in 60% of cases 4

Prognosis

With appropriate treatment, 70-85% of patients have a benign course 3. The risk of constrictive pericarditis is <0.5% for idiopathic acute pericarditis, and cardiac tamponade occurs in <3% of cases 3, 7.