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Prosthetic valve fungal endocarditis due to histoplasmosis
P A Isotalo1, K L Chan, F Rubens
1Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Canada.
Abstract:
Fungal endocarditis is associated with severe patient morbidity and mortality. Unfortunately, fungal endocarditis is difficult to diagnose because fungal pathogens are uncommonly isolated from routine blood cultures. Histopathological examination of surgically excised cardiac valves, peripheral emboli and systemic ulcers may be useful in identifying pathogens as etiological agents of culture-negative endocarditis. The authors describe a 63-year-old man who had culture-negative endocarditis. Multiple echocardiograms showed progression of the vegetations with valve stenosis despite treatment with multiple antimicrobials. He had multiple peripheral emboli before surgery. Disseminated histoplasmosis was diagnosed by bone marrow culture. Yeast organisms consistent with histoplasma were shown in the vegetations of his excised mitral valve prosthesis. The patient was treated with amphotericin and has been doing well in the two years since his surgery. The diagnosis and management of fungal endocarditis are emphasized.
Insights
Diagnosing fungal endocarditis is challenging due to infrequent pathogen detection in blood cultures. This case highlights histopathology of cardiac valves for identifying fungal causes of culture-negative endocarditis.
Area of Science:
- Cardiology
- Infectious Diseases
- Mycology
Background:
- Fungal endocarditis presents significant morbidity and mortality.
- Diagnosis is often difficult due to low rates of pathogen isolation from blood cultures.
- Histopathological examination of cardiac valves and emboli can aid in diagnosing culture-negative cases.
Observation:
- A 63-year-old male presented with culture-negative endocarditis.
- Echocardiograms revealed progressive vegetations and valve stenosis despite antimicrobial therapy.
- The patient experienced multiple peripheral emboli prior to surgical intervention.
Findings:
- Disseminated histoplasmosis was confirmed via bone marrow culture.
- Histopathological analysis of the excised mitral valve prosthesis showed yeast consistent with Histoplasma.
- Successful treatment with amphotericin was administered post-surgery.
Implications:
- This case underscores the importance of histopathology in diagnosing fungal endocarditis.
- Early and accurate diagnosis is crucial for effective management and improved patient outcomes.
- Consideration of fungal etiologies is vital in culture-negative endocarditis cases.