Bacterial infections of the CNS in neutropenic patients.

In neutropenic patients, fever and mental status changes are frequently the only overt clinical manifestations of bacterial infections of the CNS. Prominent headache and meningeal signs are exceptional. CNS infections may occur even in patients receiving large doses of broad-spectrum antibiotics. CSF culture and Gram's stain are required to establish or exclude the diagnosis and are often positive, even in patients receiving antibiotics for other indications. The CSF cell counts and chemistries are helpful if abnormal, but, when normal, provide no assurance that infection is not present. The CSF glucose can be lowered in the absence of pleocytosis, but a low CSF glucose is neither sensitive (27% in this series) nor specific. Lumbar puncture is hazardous in many neutropenic patients because of simultaneous thrombocytopenia; lumbar puncture should be performed by an experienced physician after platelet transfusions. The outcome of CNS infection depends on the underlying clinical disorder and on bone marrow recovery. The use of third-generation cephalosporins, new semisynthetic penicillins, and intrathecal administration of aminoglycosides may improve outcome.