Pericarditis for USMLE Step 3 & COMLEX-USA Level 3

• Definition: Inflammation of the pericardium, the fibrous sac surrounding the heart.

• Causes:
• Infectious: Most commonly viral (e.g., coxsackievirus, echovirus).
• Non-infectious: Autoimmune disorders (e.g., lupus), post-myocardial infarction (Dressler syndrome), uremia, radiation.
• Idiopathic: Often presumed viral when no specific cause is identified.

• Chest Pain: Sharp, pleuritic, worse with deep breathing or lying flat, improves with sitting up or leaning forward.
• Pericardial Friction Rub: Scratchy sound heard best at the left lower sternal border, often heard with the patient leaning forward.
• Other Symptoms: Dyspnea, fever, malaise.

• ECG Findings:
• Stage 1(First hours to days): ST elevation in most leads and PR depression in others. PR often elevated in aVR.
• Stage 2 (First week): ST and PR segments normalize.
• Stage 3 (Subacute phase): T-wave inversions after ST segments return to normal.
• Stage 4: ECG normalizes fully, often after treatment or as the condition resolves.

The TP segment is used as the baseline for measuring PR and ST changes.

• Echocardiography:
• Detects pericardial effusion and assesses for complications like cardiac tamponade.
• Laboratory Tests:
• Elevated CRP and ESR are commonly seen.

• Medical Treatment:
• NSAIDs: First-line therapy to reduce pain and inflammation.
• Colchicine: Prevents recurrence and reduces inflammation.
• Corticosteroids: Reserved for refractory cases, patients with NSAID contraindications (e.g., renal failure, pregnancy <20 weeks), or autoimmune conditions.
• Monitoring and Follow-Up:
• Regular assessment for cardiac tamponade and constrictive pericarditis is essential, especially in severe or recurrent cases.

• First-Line Therapy: NSAIDs and colchicine effectively reduce inflammation and recurrence.
• Complications:
• Be vigilant for cardiac tamponade—a life-threatening complication that presents with hypotension, muffled heart sounds, and jugular venous distention (Beck’s triad). This requires immediate intervention with pericardiocentesis to drain the fluid.
• Constrictive Pericarditis: Presents with signs of right heart failure (e.g., peripheral edema, hepatomegaly, ascites). Initially managed with diuretics to control fluid overload, but severe cases may require pericardiectomy for definitive treatment.
• ECG Findings: Diffuse ST elevation without reciprocal changes distinguishes pericarditis from myocardial infarction, where reciprocal depression is usually seen.
• Complication Awareness: Always consider both cardiac tamponade and constrictive pericarditis in your differential, as these complications may require immediate or surgical intervention.