This report describes a yeast-related CNS infection of a young immunocompromised man. Yeasts are pathogenic in patients with hematological neoplasms (as in our patient), solid neoplasms, acquired immunodeficiency syndrome and transplantation of bone marrow or solid organs. In our case, blood cultures were negative, as might happen in 50% of CNS fungal infections. However, diagnosis was confirmed by microscopy. In our patient the PCR assay of brain tissue was yeast positive. Amphotericin B is the drug of choice, in the absence of positive cultures and hence inability to perform susceptibility testing [
6,
7]. Despite treatment, he died. More studies are required in order to clarify the exact physiological mechanism of yeast CNS infection and the appropriate treatment. The entity is uncommon but affects predominantly neonates, neurosurgical patients and immunosuppressed patients. It has been described in patients with granulomatous disease, myeloperoxidase deficiency, severe combined immunodeficiency, human immunodeficiency virus infection, organ transplantation and lymphoma [
8]. Fungemia might precede CNS infection, while direct inoculation of the fungus may occur, for example after placement of CNS prostheses [
8]. However, in our case, blood cultures were negative, as might happen in 50% of fungemias.
Candida albicans accounts for 70% to 100% of all
Candida CNS infection cases [
9]. Table
1 depicts the previously reported cases of
Candida CNS infections. These may include cerebral microabscesses, manifesting as diffuse encephalopathy, or cerebral abscesses with focal neurologic signs, and meningitis, as in our case [
9]. A positive CSF culture establishes the diagnosis of fungal meningitis. However, in cases of failure to isolate a pathogen, perhaps because of the small inoculum size and slow growth of the yeast [
8], a brain biopsy might be considered. Recommended appropriate therapy for CNS candidiasis is liposomal amphotericin B (3 to 5mg/kg) with or without 5-flucytosine 25mg/kg every 6 hours, for several weeks, followed by fluconazole 6 to 12mg/kg daily [
8]. Despite the existing evidence for synergistic action between amphotericin and fluconazole, there is no confirmed clinical superiority of combination therapy for
Candida yeast meningitis [
10]. Despite appropriate combination treatment our patient died because of multiple brain lesions leading to diffuse brain edema. As autopsy was denied, confirmation of yeast involvement was achieved by histology and direct microscopic examination.
Table 1
Previously reported cohorts of central nervous system yeast infections
| 5 | Brain abscesses (4) |
Candida species |
J Neurosurg. 1985 Apr;62 (4):475-95.
| Meningoencephalitis (1) |
| 14 | Meningitis (14) |
C. albicans (13) |
|
C. tropicalis (1) |
| 13 | Meningitis (13) |
C. albicans (54%)
|
Folia Microbiol (Praha). 2002;47 (6):732-6.
|
C. parapsilosis ( 23%) |
C. tropicalis (15%)
|
| | |
C. krusei (8%)
|