Pericarditis is inflammation of the pericardial sac. In some patients, it is triggered by a viral infection, but in most cases, the etiology is unknown. Table 1 lists common causes of acute pericarditis.

The incidence of acute pericarditis is 27 cases per 100,000. ²⁴

Patients with acute pericarditis have the following signs and symptoms:

1. Sharp chest pain that improves by sitting up and leaning forward
2. Pericardial friction rub—a superficial scratchy or squeaky sound on auscultation
3. Pericardial effusion—the accumulation of > 50 mL of plasma ultrafiltrate within the pericardial sac
4. ECG changes—widespread ST elevation or PR depression in up to 90% of patients

Pericarditis Illustration