Use of the 1,3-β-D-Glucan Assay for the Early Detection of Fungal Endocarditis in a 45-Year-Old Man

Emerging trends in fungal endocarditis: clinical complexity, diagnostic challenges, and therapeutic implications - a case series and literature review

Background

Fungal infective endocarditis (IE) is a rare, yet increasingly recognised condition associated with substantial mortality rates. Candida and Histoplasma are among the notable causative agents, presenting diverse clinical manifestations and complexities in diagnosis and management.

Objectives

This study was undertaken to examine the clinical profiles, diagnostic challenges, treatment modalities, and outcomes of four compelling cases involving Candida and Histoplasma endocarditis.

Methods & Design

This was a descriptive case series study conducted from July 2021 to July 2023. All patients with definite/possible endocarditis diagnosed based on modified Duke's criteria were reviewed in this study. Data on demographics, risk factors, clinical signs and symptoms, echocardiography findings, microbiological aetiology, complications, treatment, and outcomes were collected.

Results

Among 212 suspected IE cases reviewed, 54 met the modified Duke's criteria for possible or definite IE, with four instances identified as fungal endocarditis. Candida species accounted for three cases, while an uncommon instance of Histoplasma Endocarditis (HE) was also observed. Clinical presentations varied, with fever and dyspnoea being prominent symptoms. Risk factors included chronic kidney disease, prior surgeries, prosthetic valves, and immunocompromised states. Diagnosis posed challenges due to the resemblance to bacterial IE, low blood culture yields, and delayed suspicion. Various diagnostic approaches, including blood cultures, serological markers, and imaging, were employed. Therapeutic strategies involved antifungal agents and surgical intervention, where feasible. However, despite prompt treatment initiation, many patients faced rapid clinical deterioration, emphasising the severity and aggressive nature of fungal endocarditis. Mortality rates remained notably high across the cohort.

Conclusion

This study highlights the criticality of early suspicion, prompt diagnosis, and a multidisciplinary approach to managing fungal endocarditis. While recognising the limitations in current diagnostic tools and therapeutic options, the study underscores the urgent need for enhanced diagnostic modalities and novel treatment strategies to improve outcomes in these challenging cases.

Prosthetic valve endocarditis due to Candida parapsilosis - a rare case report

Fungal endocarditis is a rare and fatal condition, most frequently caused by species of the genera Candida and Aspergillus. Fever and changing heart murmur are the most common clinical manifestations. The diagnosis of fungal endocarditis is challenging, with prosthetic valve endocarditis being extremely difficult to diagnose. The optimal management of the condition still remains debatable. We present a case of prosthetic valve endocarditis caused by Candida parapsilosis, managed empirically with liposomal amphotericin B, which was later shifted to combination therapy with high-dose echinocandin and fluconazole, but had a fatal outcome because the patient could not undergo timely surgical intervention. Treating C. parapsilosis endocarditis cases is difficult because of their biofilm production on native and prosthetic heart valves. A combined approach consisting of a high index of clinical suspicion, early diagnosis using serological markers followed by culture or PCR and prompt initiation of appropriate antifungals may aid in improving outcomes.

Clinical features, diagnosis and treatment outcome of fungal endocarditis: A systematic review of reported cases

The landscape of fungal endocarditis (FE) has constantly been evolving in the last few decades. Despite the advancement in diagnostic methods and the introduction of newer antifungals, mortality remains high in FE. This systematic review aimed to evaluate the epidemiology, clinical features, diagnostic and therapeutic interventions in patients with FE. We also aim to examine the aforementioned factors as a determinant of mortality in FE. A literature search was performed in PubMed, Google Scholar and Scopus, and all patients ≥18 years with proven fungal endocarditis were included. A total of 220 articles (250 patients) were included in the final analysis. Candida was the commonest aetiology (49.6%), followed by Aspergillus (30%) and Scedosporium species (3.2%). The proportion of prosthetic valve endocarditis (PVE) and intravenous drug users was 35.2% and 16%, respectively. The overall mortality rate was 40%. On multivariate analysis, Aspergillus endocarditis (HR 3.7, 95% CI 1.4-9.7; p = .009) and immunocompromised state (HR 2.8, 95% CI 1.24-6.3; p = .013) were independently associated with mortality. Patients treated with surgery along antifungals had better survival (HR 0.20, 95% CI 0.09-0.42; p < .001) compared to those treated with antifungals alone. Recurrence of FE was reported in 10.4% of patients. In conclusion, FE carries significant mortality, particularly in immunodeficient and Aspergillus endocarditis. We advocate the use of surgery combined with antifungals to improve clinical outcomes.

Mechanical Thrombectomy for Acute Ischemic Stroke Caused by Prosthetic Aortic Valve Endocarditis Due to Exophiala dermatitidis Infection: A Case Report

Prosthetic valve endocarditis (PVE) can cause large cerebral vessel occlusion. Many reports suggested that mechanical thrombectomy (MT) is effective and useful for early diagnosis from the histopathological findings of thrombus. We present the case of a 62-year-old man, with a history of prosthetic aortic valve replacement and pulmonary vein isolation for his atrial fibrillation, who developed a high fever and an acute neurological deficit, with left hemiplegia and speech disorder. He was diagnosed as having an acute right middle cerebral artery embolism and underwent an MT. The embolic source was found to be a PVE vegetation. However, histopathological analysis of the thrombus could not detect the actual diagnosis. Although he was treated for bacterial endocarditis, his blood culture revealed a rare fungal infection with Exophiala dermatitidis not until >3 weeks after admission. Subsequently, a ß-D-glucan assay also indicated elevated levels. Although he underwent an aortic valve replacement on day 36, MRI showed multiple minor embolic strokes till that day. Early diagnosis of fungal endocarditis and detection of the causative pathogen are still challenging, and the disease has a high risk of occurrence of early and repeated embolic stroke. In addition to clinical findings and pathological studies, ß-D-glucan assay might be a good tool for the diagnosis and evaluation of fungal endocarditis.