Pericarditis for USMLE Step 1 & COMLEX-USA Level 1
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Overview of Pericarditis
- Definition: Inflammation of the pericardium, the fibrous sac surrounding the heart.
Etiology
- Causes:
- Infectious: Most commonly viral (e.g., coxsackievirus, echovirus).
- Non-infectious: Autoimmune disorders (e.g., lupus, rheumatoid arthritis), uremia, following myocardial infarction (Dressler’s syndrome), or radiation therapy.
Pathophysiology
- Inflammatory Response: Leads to the production of fibrinous exudate or serous fluid in the pericardial space.
- Complications: Can progress to pericardial effusion or constrictive pericarditis.
Clinical Presentation
- Chest Pain: Sharp, worsens with inspiration and improves when sitting up and leaning forward.
- Pericardial Friction Rub: A scratchy, high-pitched sound heard best at the left sternal border when the patient leans forward.
Diagnosis
- ECG Findings:
- Widespread ST elevation and PR depression in the acute phase.
- Echocardiogram:
- May show pericardial effusion.
Management
- Medical Treatment:
- NSAIDs for pain and inflammation.
- Colchicine to reduce inflammation and prevent recurrence.
- Corticosteroids in refractory or severe cases.
Essential Points for Step 1
- ECG Changes: Remember that ST elevation in pericarditis is diffuse and not localized to specific leads as in myocardial infarction.
- Differentiation: Distinguish from acute myocardial infarction based on pain characteristics, ECG changes, and lack of cardiac enzyme elevation.
- Complication Awareness: Be aware of potential complications like tamponade and constrictive pericarditis, which may require more aggressive interventions.