Endocarditis Differential Diagnosis

The following differential diagnosis is organized into categories to help guide the thought process:

• Single Most Likely Diagnosis

  • Infective Endocarditis: This is the most likely diagnosis, given the context of the question. It is a condition where the inner lining of the heart, particularly the heart valves, becomes infected. This diagnosis is likely due to the direct reference to endocarditis in the question.

• Other Likely Diagnoses

  • Non-bacterial Thrombotic Endocarditis (NBTE): Also known as marantic endocarditis, this condition involves the formation of small sterile vegetations on the heart valves, often associated with hypercoagulable states or malignancies.
  • Libman-Sacks Endocarditis: This is a form of non-bacterial endocarditis seen in patients with systemic lupus erythematosus (SLE), characterized by the formation of vegetations on either side of the valve leaflets.

• Do Not Miss Diagnoses

  • Acute Rheumatic Fever: Although less common in areas with access to antibiotics, acute rheumatic fever can present with cardiac manifestations, including endocarditis-like symptoms, and is crucial not to miss due to its potential for long-term cardiac damage.
  • Prosthetic Valve Dysfunction: In patients with a history of valve replacement, dysfunction of the prosthetic valve can mimic endocarditis and is critical to diagnose promptly due to its implications for patient management and potential need for urgent intervention.

• Rare Diagnoses

  • Infective Endocarditis due to Unusual Organisms: While less common, endocarditis can be caused by a variety of unusual organisms, including fungi (e.g., Candida), HACEK organisms, or other fastidious bacteria. These are rare but important to consider in the appropriate clinical context.
  • Tumor Embolism: Rarely, cardiac tumors such as myxomas can embolize and mimic the clinical presentation of endocarditis, particularly if they lead to systemic emboli.
  • Antiphospholipid Syndrome: This autoimmune disorder can lead to valvular lesions and vegetations that resemble those seen in endocarditis, although the pathophysiology is different.