Cryptococcal meningitis associated with increased adenosine deaminase in the cerebrospinal fluid

INTRODUCTION: Clinically, increased cerebrospinal fluid (CSF) adenosine deaminase (ADA) level is an important diagnostic clue of tuberculous meningitis. However, increased CSF ADA level can be caused by other neurological diseases. CASE DESCRIPTION: We report a case of a 67-year-old woman with cryptococcal meningitis presented with increased ADA level of the CSF. In parallel with her recovery, the ADA level of CSF decreased steadily. This is the first case described the chronological change in CSF ADA level of the patient with cryptococcal meningitis in detail. DISCUSSION AND EVALUATION: Clinically, increased CSF ADA level is an important diagnostic clue of tuberculous meningitis. However, previously, it was reported that increased CSF ADA level can be caused by other neurological diseases. In this case, the patient was diagnosed with cryptococcal meningitis, and the possibility of coinfection with tuberculous meningitis has been discarded by the negative PCR, negative cultures and the clinical course. In addition, the chronological change in CSF ADA level was useful for follow-up assessment. CONCLUSIONS: Cryptococcal meningitis should be considered for the differential diagnosis for diseases presented increased CSF ADA.