MCQ: Infective Endocarditis

Explanation

Correct answer: C. Transesophageal echocardiography (TEE)

This child has a high clinical suspicion of infective endocarditis, persistent fever despite antibiotic therapy, a history of repaired congenital heart disease, and an inconclusive transthoracic echocardiogram (TTE).

TEE is the most appropriate next imaging investigation because it provides better visualization of cardiac valves, intracardiac structures, and certain prosthetic materials than TTE. It may detect vegetations, abscesses, or other complications that are not adequately visualized on transthoracic imaging.

In patients with suspected infective endocarditis and a negative or nondiagnostic TTE, the 2023 European Society of Cardiology (ESC) guidelines recommend TEE. If the initial echocardiographic examination remains inconclusive and clinical suspicion persists, repeat TTE or TEE within 5–7 days is recommended.

The history of repaired tetralogy of Fallot is important because residual lesions, conduits, patches, or other prosthetic material may complicate the assessment. The exact anatomy of the previous repair should be reviewed.

Why the other options are incorrect

A. Add vancomycin — Incorrect

Persistent fever despite ceftriaxone may raise concern for an inadequately treated infection, resistant organisms, or a noninfectious cause. However, changing or broadening antibiotics does not address the immediate diagnostic problem of an inconclusive echocardiogram. Antibiotic decisions should be made with an infectious diseases specialist and guided by the clinical condition, prior antibiotic exposure, local resistance patterns, and the suspected organisms.

B. Repeat blood cultures — Incorrect as the next best answer

Repeat blood cultures are important in suspected blood culture-negative infective endocarditis, particularly when the child remains febrile. However, the question specifically highlights poor acoustic windows and an inconclusive TTE. The most appropriate next imaging step is TEE. Further microbiological evaluation should continue alongside cardiac imaging.

C. Transesophageal echocardiography — Correct

TEE is indicated when clinical suspicion of IE remains high and TTE is negative, nondiagnostic, or technically inadequate. It can provide improved visualization of vegetations, valvular structures, abscesses, and prosthetic material. In this child, TEE is therefore the most appropriate next investigation.

D. PET-CT scan — Incorrect as the initial next investigation

FDG-PET/CT can be useful in selected cases of prosthetic valve or prosthetic-material-associated infective endocarditis, particularly when echocardiography is inconclusive. However, it is not generally the first additional cardiac imaging test in a child with suspected IE and a nondiagnostic TTE. TEE should be considered first. PET-CT may be considered later in a specialist center if diagnostic uncertainty persists and prosthetic-material infection is suspected.

E. Stop antibiotics — Incorrect

Persistent fever and negative blood cultures do not exclude infective endocarditis, particularly after prior antibiotic treatment. Stopping antibiotics solely because cultures are sterile and TTE is inconclusive would be inappropriate when clinical suspicion remains high. Further diagnostic evaluation and specialist review are required.

Clinical pearl

Suspected infective endocarditis + negative or nondiagnostic TTE → TEE.

If TEE is also negative or inconclusive but clinical suspicion remains high, repeat echocardiography after 5–7 days and consider a multimodality imaging approach, including cardiac CT or FDG-PET/CT in selected patients with prosthetic material.

Reference

Delgado V, Marsan NA, de Waha S, et al. 2023 ESC Guidelines for the management of endocarditis. Eur Heart J. 2023;44(39):3948–4042. doi:10.1093/eurheartj/ehad193.

You can also practice another MCQ on infective endocarditis.