Invasive fungal infections are severe infections in which fungal pathogens invade normally sterile body sites. They predominantly affect immunocompromised patients, including those with neutropenia, hematologic malignancies, solid organ or stem cell transplants, and prolonged corticosteroid or broad-spectrum antibiotic use.
Common Pathogens
- Candida species (most frequent cause of bloodstream infections)
- Aspergillus species (primarily pulmonary infections)
- Cryptococcus species (commonly CNS involvement)
- Emerging molds and rare fungi in high-risk populations
Risk Factors
- Immunosuppression (neutropenia, chemotherapy, transplant)
- Indwelling catheters or prosthetic devices
- Prolonged ICU stay and broad-spectrum antibiotic exposure
Clinical Presentation
- Symptoms vary by site of infection and may include fever, organ dysfunction, respiratory distress, or neurological deficits
Diagnosis
- Culture and microscopy from sterile sites
- Antigen/antibody testing (e.g., β-D-glucan, galactomannan, cryptococcal antigen)
- Imaging studies (CT, MRI) for organ involvement
- Histopathology when feasible
Management Principles
- Early initiation of targeted antifungal therapy
- Source control, including removal of infected catheters or drainage of abscesses
- Selection of therapy guided by species identification and antifungal susceptibility
- Multidisciplinary approach with infectious diseases consultation
Prognosis
- Dependent on timely diagnosis, host immunity, and pathogen virulence
- Delays in treatment significantly increase morbidity and mortality
