Diagnosing pericarditis.

Pericarditis, or inflammation of the pericardium, is most often caused by viral infection. It can also develop as a result of bacterial or other infection, autoimmune disease, renal failure, injury to the mediastinal area, and the effects of certain drugs (notably hydralazine and procainamide). The clinical features of pericarditis depend on its cause, as well as the volume and type of effusion. Patients with uncomplicated pericarditis have pleuritic-type chest pain that radiates to the left shoulder and may be relieved by leaning forward. Chest radiographs, Doppler studies, and laboratory tests confirm the diagnosis and provide information about the degree of effusion. In most patients, pericarditis is mild and resolves spontaneously, although treatment with a nonsteroidal anti-inflammatory drug or a short course of a corticosteroid may be helpful. When a large pericardial effusion is produced, cardiac function may be compromised, and cardiac tamponade can occur. In patients with longstanding inflammation, the pericardium becomes fibrous or calcified, resulting in constriction of the heart. Drainage or surgical intervention may be necessary in patients with complicated pericarditis.