The dusky finger: anterior mitral valve aneurysm secondary to probable infective endocarditis.

The patient is a 75-year-old male with bullous pemphigoid on chronic glucocorticosteroids. He presented with an infected left middle finger gangrene and was afebrile. Wound cultures were positive for streptococcus dysgalactiae, but blood cultures were negative. Upper limb arterial investigations were suggestive of an embolic phenomenon.

Transthoracic echocardiogram (TTE) showed multiple vegetations on the mitral () and aortic valves, and mild mitral and aortic regurgitation, while transoesophageal echocardiogram confirmed the presence of vegetations and an anterior mitral valve aneurysm (MVA) (Video 1). The patient underwent left middle finger ray amputation and completed 6 weeks of antibiotics. The patient declined surgical intervention and repeat TTE showed stable findings.

Figure 1

(A) Transthoracic echocardiogram image of vegetations on anterior (yellow arrow) and posterior mitral valve (white arrow) leaflets. (B) Transoesophageal echocardiogram image of the anterior mitral valve aneurysm (red dotted circle), and mitral valve vegetation (red arrow). (C) Transoesophageal echocardiogram image of the aortic valve vegetation (yellow arrowhead). (D) 3D transoesophageal echocardiogram image of the mitral valve. Aneurysm seen on the anterior mitral valve leaflet (red dotted circle). Aortic and mitral valves as labelled.

Our case highlights the challenge of diagnosing IE early in atypical presentations. This may lead to late complications such as large vegetations and MVAs. The patient’ initial clinical sign, an isolated septic embolism leading to peripheral artery occlusion in the absence of fever and positive blood cultures, was highly uncommon. Patients on chronic glucocorticosteroids may not manifest typical signs and symptoms of infection due to inhibition of cytokine release, and reduction in febrile and inflammatory responses.

Mitral valve aneurysms are also uncommon and often associated with aortic valve IE. Postulated mechanisms include haematogenous spread, direct contact, and extension of infection via the intervalvular fibrosa,. Prompt diagnosis is necessary to avoid complications such as thrombosis, embolization, perforation, or rupture of the MVA. Surgical intervention to repair the mitral valve is preferred in large vegetations and significant valvular regurgitation. The literature remains divided on the management of MVA without significant valvular regurgitation as no definite guideline or data exists. Our case shows that MVA can be managed conservatively in the absence of significant valvular regurgitation or complications.

In summary, our case highlights the challenges of diagnosing IE in an immunocompromised host and the development of MVA as an uncommon complication.