Pericarditis

Pericarditis is an inflammation of the pericardium (the fibrous sac surrounding the heart). Pericarditis is further classified according to the composition of the inflammatory exudate: serous, purulent, fibrinous, and hemorrhagic types are distinguished (images).

Acute pericarditis is more common than chronic pericarditis, and can occur as a complication of infections, immunologic conditions, or heart attack.

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Clinical presentation

Chest pain, radiating to the back and relieved by sitting up forward and worsened by lying down, is the classical presentation. Other symptoms of pericarditis may include dry cough, fever, fatigue and anxiety. Pericarditis can be misdiagnosed as myocardial infarction (heart attack), and vice versa.

The classic sign of pericarditis is a friction rub. Other signs include diffuse ST-elevation and PR-depression on EKG (all leads); cardiac tamponade (pulsus paradoxus with hypotension), and congestive heart failure (elevated jugular venous pressure with peripheral edema).

Pathophysiology

Causes

• Idiopathic No identifiable etiology found after routine testing.
• Viral infection, especially by Coxsackie virus (most common cause)
• Bacterial infection, especially by the Tuberculosis bacillus
• Immunologic conditions including Lupus erythematosus (more common among women)
• Myocardial Infarction (Dressler's syndrome)
• Trauma to the heart, e.g. puncture, resulting in infection or inflammation
• Uremia
• Malignancy (as a paraneoplastic phenomenon)
• Side effect of some medications, e.g. isoniazid, cyclosporine, hydralazine
• Radiation induced
• Aortic dissection
• Tetracyclines

Complications

Most cases of acute idiopathic pericarditis resolve without complications or recurrence. Complications may include:

• Pericardial effusion
• Constrictive pericarditis
• Cardiac tamponade [1]

Fibrinous pericarditis

Fibrinous pericarditis is an exudative inflammation. The pericardium is infiltrated by the fibrinous exudate. This consists of fibrin strands and leukocytes. Fibrin describes an amorphous, eosinophilic (pink) network. Leukocytes (mainly neutrophils) are found within the fibrin deposits and intrapericardic. Vascular congestion is also present. The myocardium has no changes. Sometimes referred to as having "Bread and Butter Appearance". Photo at: Atlas of Pathology

Pericarditis due to Tuberculosis

Pericarditis caused by tuberculosis is difficult to diagnose, because definitive diagnosis requires culturing Mycobacterium tuberculosis from aspirated pericardial fluid or pericardial biopsy, which requires high technical skill and is often not diagnostic (the yield from culture is low even with optimum specimens). The Tygerberg scoring system helps the clinician to decide whether pericarditis is due to tuberculosis or whether it is due to another cause: night sweats (1 point), weight loss (1 point), fever (2 point), serum globulin > 40g/l (3 points), blood total leucocyte count <10 x 10⁹/l (3 points); a total score of 6 or more is highly suggestive of tuberculous pericarditis.^[1] Pericardial fluid with an interferon-γ level greater than 50pg/ml is highly specific for tuberculous pericarditis.

Treatment

The treatment in viral or idiopathic pericarditis is with non-steroidal anti-inflammatory drugs. Severe cases may require:

• pericardiocentesis
• antibiotics
• steroids
• colchicine
• surgery

References

1. ^ Reuter H, Burgess L, van Vuuren W, Doubell A. (2006). "Diagnosing tuberculous pericarditis". Q J Med 99: 827–39. PMID 17121764.