A case of chronic meningitis caused by Cryptococcus neoformans, which was detected only with the use of mycobacterial blood culture bottle for cerebrospinal fluid

Background: Cryptococcus is known to cause chronic meningitis. Diagnosis is usually made with the use of cryptococcus antigen test of cerebrospinal fluid (CSF). Despite its high sensitivity, false negative result can occur, particularly then the amount of the organism in CSF was small. We herein report a case of cryptococcal meningitis in a non-HIV patient, with negative india ink, negative CSF cryptococcal antigen test, negative routine CSF fungal culture, and positive only with the use of mycobacterial blood culture bottle. Methods & Materials: The patient is 38-year-old man without significant past medical history, who presented with gait instability for 40 days. He also complained of intermittent headache since 20 days prior to the first visit, which worsened gradually. He started to feel weak on his left lower extremity, and had difficulty in standings up. On physical examination, he was alert but disoriented. His neck was supple, but had gait instability. Head magnetic resonance imaging study only showed widening of lateral ventricles. Cerebrospinal fluid examination revealed opening pressure was 24.5 cmH2O, cell count 143/μL with 87% polymorphonuclear cells, protein 184 mg/dL, glucose 7 mg/dL, with negative Gram staining, acid fast bacilli staining, india ink staining, and cryptococcal antigen test. Results: Cryptococcus neoformans var grubii was detected only from mycobacterial culture bottle 7 days later, despite negative routine fungal culture. He was treated with amphotericin B lipid complex and flucytosine, together with spinal drainage, followed by fluconazole maintenance therapy for 6 months. His neurological abnormalities improved without recurrence Conclusion: Cryptococcal antigen test of CSF has high sensitivity for the diagnosis of meningitis, but false negative still can occur. Previous studies suggest that the use of mycobacterial blood culture bottle may increase the sensitivity of fungemia in general. There is no literature reporting the use of mycobacterial blood culture bottle for the diagnosis of cryptococcal meningitis. The use of it on CSF, on top of conventional work up, may heighten the diagnostic yield of this infection.