At autopsy, changes of pericarditis appear in 2 to 6 percent of cases. The majority of cases are idiopathic or postviral, but acute myocardial infarction, uremia, bacterial infection, tuberculosis, collagen-vascular disease, neoplasm, and trauma must be considered. Recumbency increases the pain, which often radiates to the trapezius ridge. Swallowing may exacerbate pain. Dyspnea results from pleural irritation or, on occasion, accumulation of a large pericardial effusion.
Symptoms typically occur with an ongoing or preceding upper respiratory infection.
Exertion may exacerbate chest pain, but the pleuritic nature and positional component persist. When pericarditis follows myocardial infarction, ischemic chest pain precedes. Coexistent symptoms of pneumonitis suggest a bacterial etiology, especially with high fever. Recurrent fevers, sweats, and weight loss suggest tuberculosis. Malignant pericarditis is usually metastatic with other clinical evidence of malignancy.