MICROSCOPY AND LATEX ANTIGEN NEGATIVE CRYPTOCOCCAL MENINGITIS

A HIV-positive patient presented with cryptococcal meningitis that was not detected by cerebrospinal fluid (CSF) latex antigen and direct mi croscopy. The diagnosis was confirmed by culture of the CSF and subseq uent urine culture, both of which yielded an apparently acapsular stra in of Cryptococcus neoformans. After 19 months the patient relapsed an d capsulated yeasts were observed on this occasion on direct microscop y of the CSF The latex antigen test was strongly positive, Culture aga in yielded an apparently acapsular isolate. Retrospective culture of a ll isolates obtained fi om this patient in sterile CSP resulted in the formation of capsules. This was confirmed by the requirement of norma l non heat inactivated serum for neutrophil-cryptococcus attachment to occur in vitro, Although antigen and direct microscopy are frequently relied upon to diagnose cryptococcus meningitis, a negative result do es not exclude the condition.