Streptococcus pneumoniae meningitis without pleocytosis of the cerebrospinal fluid

Pleocytosis of the cerebrospinal fluid is a key finding for the diagnosis of bacterial meningitis. Bacterial meningitis presenting in normal cerebrospinal fluid is rare in adult patients. We describe the case of a patient with pneumococcal meningitis without cerebrospinal fluid pleocytosis. This case suggests that immediate antibiotic therapy should be started when meningitis is suspected, even with normal cerebrospinal fluid findings. (See Figure.)