Clinical vignette
Septic peripheral embolization from Haemophilus parainfluenzae endocarditis
Hee-Hwa Ho*, Chi-Wai Cheung, and Chi-Keung Yeung
Department of Medicine, Division of Cardiology, Queen Mary Hospital, Pokfulam Road, Hong Kong, Hong Kong
*Corresponding author. E-mail address: heehwa@attglobal.net
A 40-year-old, previously healthy lady with good dentition, presented with pyrexia of unknown origin for 6 weeks. Physical examination was unremarkable. Initial cultures were negative. Rheumatoid factor was elevated but she did not have any joint symptoms. Because of severe thrombocytopenia which developed during hospitalization, bone marrow examination was done, which showed normal megakaryocytic activity and reactive haemophagocytosis. Marrow cultures subsequently yielded Haemophilus parainfluenzae. However, transthoracic and transesophageal echocardiogram did not show any vegetation. She then developed a painful localized erythematous swelling on her right foot (Panel A). In view of unabating fever and unknown primary focus of infection, a positron emission tomography (PET) scan was performed, which revealed a splenic embolic infarct and intense uptake at cardiac fibrous ring near aortic root (Panels B and C). A computed tomography (CT) of the heart demonstrated a vegetation 0.7×1.3 cm2 at tip of anterior mitral valve leaflet (ventricular surface) which extended into the chordae (Panel D). The evolving clinical picture was suggestive of infective endocarditis with septic peripheral embolization. She eventually underwent mitral valvular surgery because of suboptimal clinical response and post-operatively, made an uneventful recovery.
Haemophilus endocarditis often produces bulky valvular lesions and is frequently complicated by arterial embolization. Special culture medium is necessary for isolation of Haemophilus species because it is a slow growing microorganism.
Panel A. Focal area of inflammation on right foot (encircled) due to septic microemboli.
Panel B. PET scan showing wedge-shaped hypodense area at anterior aspect of spleen with no metabolism with adjacent focus of increased glycolysis (white arrow).
Panel C. PET scan showing hypermetabolic focus at base of left ventricle near aortic root (white arrow).
Panel D. Dynamic gated CT of the heart showing large vegetation at anterior mitral valve leaflet (black arrow).
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