Acute Pericarditis High Yield

Introduction

Pericarditis is an inflammation of the pericardium, the double-layered sac that surrounds and protects the heart.

Pathophysiology

The pericardium has two main layers: the Fibrous pericardium (outer layer)—a tough covering that anchors the heart—and the Serous pericardium (inner layer). The serous layer is further divided into the Parietal layer (lines the fibrous pericardium) and the Visceral layer (also called the epicardium, directly covering the heart).

Between these layers lies the pericardial cavity, normally containing a small amount of lubricating fluid to reduce friction during cardiac movements.

In acute pericarditis, inflammation leads to the infiltration of immune cells (mainly neutrophils and lymphocytes) and excess fluid production, forming a pericardial effusion. Depending on the cause, this fluid may be fibrinous, serous, hemorrhagic, or purulent.

Large or rapidly accumulating effusions can cause cardiac tamponade, while persistent inflammation may result in fibrosis and adhesions, limiting pericardial elasticity (leading to constrictive pericarditis).

Clinical Presentation

Classic features include:

1. Chest pain – Sharp, pleuritic, substernal pain radiating to neck, shoulders, or back.
   Key Feature: Pain worsens with inspiration or lying flat, and is relieved by sitting up and leaning forward.
2. Fever – Often low-grade due to systemic inflammation.
3. Pericardial friction rub – A high-pitched, scratchy sound best heard along the left sternal border when leaning forward; may have 3 components.
4. Pericardial effusion – If significant, signs of cardiac tamponade (hypotension, tachycardia, pulsus paradoxus) may develop.

Diagnosis

Diagnosis is mainly clinical, supported by investigations:

• ECG Findings:
  • Diffuse concave-upward ST elevation and PR depression (not localized to coronary territories).
  • Note: ST changes are typically absent in uremic pericarditis.
• Chest X-ray: Often normal; may show cardiomegaly if large effusion exists.
• Echocardiography: Detects effusion and signs of tamponade (RA/RV diastolic collapse).
• Blood Tests: Elevated ESR, Elevated CRP, leukocytosis may be seen.
• Pericardial Fluid Analysis: Performed if significant effusion, tamponade, or suspicion of bacterial/malignant disease (cytology, cultures).

Management

1. Viral / Idiopathic Pericarditis:
   • NSAID (e.g., ibuprofen or aspirin) + Colchicine → preferred combination to reduce recurrence.
   • Corticosteroids → reserved for autoimmune causes or NSAID contraindications (avoid if possible due to high recurrence risk).
2. Post-MI (Peri-infarction / Dressler’s):
   • Aspirin + Colchicine are preferred.
   • Avoid non-aspirin NSAIDs and corticosteroids as they can delay myocardial healing.
3. Uremic Pericarditis:
   • Dialysis after excluding tamponade.
4. Bacterial / Malignant Pericarditis:
   • Treat underlying cause (e.g., antibiotics, chemotherapy, or pericardial drainage).

General Advice: Strict rest and avoidance of strenuous physical activity during recovery.

Complications

• Cardiac Tamponade – Rapid effusion causing chamber compression, reduced filling, and shock.
• Recurrent Pericarditis – Returns after initial recovery (seen in approximately 15–30% of cases).
• Constrictive Pericarditis – Chronic scarring and stiffening of pericardium causing right-sided heart failure.

Prognosis

• Viral/Idiopathic cases: Excellent recovery in weeks with proper treatment.
• Non-viral causes: Prognosis depends on the underlying disease (e.g., malignancy, renal failure).

Summary Table

Feature	Details
Common Causes	Viral, Idiopathic, Autoimmune, Uremic, Post-MI
Key Symptoms	Pleuritic chest pain reduced when sitting up, fever, pericardial rub
Investigations	ECG: Diffuse ST elevation & PR depression, Echo: Effusion
Treatment	NSAID + Colchicine (± Steroids if indicated)
Major Complications	Tamponade, Recurrent, Constrictive pericarditis