Diagnostic Workup for Pericarditis
The diagnostic workup for pericarditis requires a systematic two-level approach starting with basic tests for all patients, followed by more advanced investigations for those with high-risk features or inconclusive initial results. 1, 2
First-Level Diagnostic Evaluation (Required for All Patients)
Clinical Assessment
- Auscultation: Listen carefully for pericardial friction rub (may be mono-, bi-, or triphasic and often transient) 2
- ECG: Look for diffuse ST-segment elevation, PR-segment depression, and ST-segment depression in lead aVR (present in ~60% of cases) 2
- Transthoracic echocardiography: Evaluate for pericardial effusion and rule out cardiac tamponade 1
- Chest X-ray: May range from normal to "water bottle" heart shadow (visible only with effusions >300 ml) 2
Laboratory Tests
- Inflammatory markers: C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count with differential 1
- Renal function and liver tests: To assess organ function and guide therapy options 1
- Thyroid function: To rule out thyroid-related causes 1
- Cardiac injury markers: Troponins and creatine kinase (CK) to identify possible myocardial involvement 1
Second-Level Diagnostic Evaluation (For High-Risk Patients)
Advanced Imaging
- Cardiac MRI (CMR): Provides detailed assessment of pericardial inflammation and myocardial involvement 1, 2
- Chest CT: Evaluates pericardial thickness and calcification 1, 2
Invasive Procedures
- Pericardiocentesis: Indicated for:
- Cardiac tamponade
- Suspected bacterial or neoplastic pericarditis
- Symptomatic moderate to large effusions not responding to medical therapy 1
Analysis of Pericardial Fluid
- Cytology: Cell count and differential, cytological analysis for malignant cells 1
- Biochemistry: Protein, LDH, glucose, adenosine deaminase (ADA) 1
- Microbiology:
- PCR for tuberculosis
- Aerobic and anaerobic cultures
- Mycobacterium cultures 1
High-Risk Features Requiring More Extensive Evaluation
Patients with any of these features should undergo second-level testing:
- Fever >38°C
- Subacute course (symptoms developing over several days or weeks)
- Large pericardial effusion (>20 mm in diastole) or cardiac tamponade
- Failure to respond to NSAIDs
- Immunocompromised state 1, 2
Special Considerations
Regional Differences
- In developing countries with high TB prevalence (e.g., sub-Saharan Africa), TB testing should be prioritized as it accounts for 70-80% of pericarditis cases 1
- In developed countries, idiopathic/viral causes account for 80-90% of cases 3
Common Pitfalls to Avoid
- Missing the diagnosis: Remember that at least 2 of 4 criteria are required (pericarditic chest pain, pericardial friction rub, ECG changes, pericardial effusion) 2
- Inadequate follow-up: CRP should be monitored until normalization to guide treatment duration 2
- Premature corticosteroid use: Corticosteroids should be reserved as second-line therapy only after NSAIDs/colchicine failure 2
- Insufficient evaluation in high-risk patients: Full etiological workup is essential in patients with high-risk features 1
By following this systematic approach to the diagnostic workup of pericarditis, clinicians can effectively identify the cause, assess severity, and guide appropriate treatment to improve patient outcomes and reduce complications.