The nurse is assessing a client with pericarditis. Which finding is characteristic of this condition?

Pericarditis is inflammation of the pericardial sac surrounding the heart. Its hallmark clinical feature is sharp, pleuritic chest pain that is characteristically worsened when lying supine and relieved when the client sits upright and leans forward. This positional relief occurs because leaning forward reduces the pressure of the inflamed visceral and parietal pericardial layers against each other and against adjacent structures such as the diaphragm. The nurse should also expect a friction rub on auscultation, which is pathognomonic of pericarditis. Pitting edema in the lower extremities is more consistent with heart failure or constrictive pericarditis in its chronic form, not acute pericarditis. Muffled heart sounds (S1 and S2) are characteristic of pericardial effusion or cardiac tamponade, in which fluid accumulates in the pericardial space and dampens heart sounds, rather than simple pericarditis. Hemoptysis suggests a respiratory or pulmonary vascular condition such as pulmonary embolism, tuberculosis, or lung cancer, and is not associated with pericarditis. Recognizing that the forward-leaning position relieves pain is a critical assessment finding that helps the nurse differentiate pericarditis from myocardial infarction, where pain is not positional.