How can connective tissue diseases cause pericarditis?

Connective tissue diseases, such as systemic lupus erythematosus (SLE), can cause pericarditis—the inflammation of the membranous sac surrounding the heart—as a direct manifestation of the underlying disease process.12

In the context of systemic autoimmune conditions, the body’s immune system produces antibodies that mistakenly target its own tissues, including the membranes lining body cavities. When this inflammatory response affects the pericardium, it leads to the clinical condition known as pericarditis. This inflammation may be accompanied by an outpouring of fluid into the pericardial sac. If this fluid accumulates rapidly or in excessive amounts, it can lead to cardiac tamponade, a serious condition that restricts the heart's ability to fill with blood and reduces cardiac output.213

Treatment for pericarditis associated with connective tissue disease focuses on managing the systemic inflammation using corticosteroids or nonsteroidal anti-inflammatory drugs (NSAIDs) to limit damage to vital organs.23