Final answer:
The most likely cause of pericarditis a few days after cardiac surgery is postpericardiotomy syndrome, a reaction to surgical trauma, rather than infection, reperfusion injury, hemorrhage, or thrombosis.
Step-by-step explanation:
The most likely cause of pericarditis a few days after cardiac surgery is postpericardiotomy syndrome. This condition is typically a reaction from the body to the surgical procedure and involves inflammation subsequent to the surgical trauma. It is not typically caused by infection, reperfusion injury, hemorrhage, or thrombosis in the immediate post-operative period, although those factors can contribute to pericardial complications at different times.
Acute pericarditis after cardiac surgery can present symptoms like chest pain, difficulty breathing, and a dry cough. It is often self-limiting, but may require medical intervention if symptoms persist or worsen. Diagnosis of pericarditis can be aided by chest radiograph, electrocardiogram, echocardiogram, or evaluation of pericardial fluid and pericardial biopsy if necessary.