A patient develops chest pain and fever two weeks after an MI, with a new friction rub found on examination. What is the most likely diagnosis?

The most likely diagnosis in this scenario is Dressler's syndrome, which is characterized by the development of chest pain, fever, and a pericardial friction rub occurring weeks to months after a myocardial infarction (MI). Dressler's syndrome is classified as a type of post-myocardial infarction syndromic reaction and is believed to be an autoimmune response to the necrotic myocardium.

The presence of a friction rub is particularly significant as it indicates inflammation of the pericardium, which aligns with the findings of Dressler's syndrome. The timing—two weeks after the MI—further supports this diagnosis, as Dressler's syndrome typically presents several weeks following the event rather than immediately. This condition is often self-limiting but may require non-steroidal anti-inflammatory drugs (NSAIDs) for symptom relief.

Congestive heart failure could also present with chest pain, but it is generally associated with signs of fluid overload rather than a friction rub or a post-MI inflammatory response. New myocardial infarction would typically present more acutely rather than two weeks post-event. Pneumonia could cause fever and chest pain but would not typically produce a pericardial friction rub, making Dressler's syndrome the