In intravenous drug user with fever and Osler nodes, which diagnostic test would confirm suspected endocarditis?

• A. Chest radiography
• B. Computed tomography
• C. Echocardiography
• D. Electrocardiography

Answer: (C)

Endocarditis is diagnosed by directly showing infection of the heart valves, not just by symptoms or blood tests. Imaging that visualizes the valves can confirm the diagnosis because it can reveal vegetations—these are the mobile, echo-dense masses that grow on valve leaflets in infective endocarditis. In this scenario of an IV drug user with fever and Osler nodes, echocardiography is the test that provides this direct evidence.

There are two main echo approaches. Transthoracic echocardiography is noninvasive and often sufficient for detecting right-sided vegetations, which are common in IV drug users. If the initial study is nondiagnostic or if there’s high suspicion of involvement of other valves or complications, transesophageal echocardiography is more sensitive because it gives a closer, clearer view of the valves and can detect smaller vegetations, abscesses, or prosthetic valve involvement.

A positive echocardiogram would show a new vegetation on a valve with or without new valvular regurgitation, which confirms the diagnosis within the clinical context. Other tests like chest radiography, CT, or ECG don’t visualize vegetations and are used mainly for assessing complications or electrical activity, not to confirm endocarditis.