Candida albicans is a yeast that is present in the mouth and gastrointestinal tract in 40%–60% of healthy adults. In individuals with disrupted local defenses or depressed immunity, overgrowth and parenchymal invasion can occur, with the potential for systemic spread. Associated infections include oral lesions (thrush) and vaginal, skin, esophageal, and urinary tract involvement. Chronic mucocutaneous lesions may occur in persons with specific T-lymphocyte defects. Disseminated disease can involve any organ system, most commonly the kidneys, brain, heart, and eyes, and is more common in immunocompromised patients and those with indwelling vascular catheters.
Other important invasive fungal infections are cryptococcosis, histoplasmosis, blastomycosis, aspergillosis, and coccidioidomycosis. Invasive fungal infections are a major problem in immunocompromised patients. Fungal PCR assays allow more rapid diagnosis of serious fungal infections and offer higher sensitivity compared with fungal cultures.
Treatment of serious systemic infections has traditionally involved the use of intravenous amphotericin B, sometimes combined with flucytosine or an imidazole. Lipid complex and liposome-encapsulated formulations of amphotericin B were developed to reduce the nephrotoxic and myelosuppressive effects of this drug. Imidazoles, such as fluconazole, itraconazole, and voriconazole, are less toxic and better-tolerated alternatives. Please see the section Antifungal Agents later in this chapter.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.