Infections in neurologic surgery. The intraventricular use of antibiotics.

Intraventricular antibiotic therapy appears to be a useful treatment modality in those CSF infections in which systemic therapy may fail. Consideration should be given to using this form of treatment when infecting organisms are only sensitive to antibiotics with poor penetration of the CSF (e.g., aminoglycosides and vancomycin) and for cases in which intravenous therapy has failed to sterilize the CSF, toxicity from systemic therapy precludes further increases in dosages, and shunts or other CSF hardware might be expected to reduce the efficacy of systemic therapy by providing a foreign body to harbor organisms. Shunts or reservoirs that are infected may be successfully sterilized with IVT therapy alone or in conjunction with systemic therapy, but this has a lower success rate than cases in which the shunt is removed. There is a wealth of clinical experience with IVT vancomycin and gentamicin that suggests that they are relatively safe. Until more data are available on other aminoglycosides and newer antibiotics, these two agents should be considered the antibiotics of choice for IVT therapy. In situations in which the organism is sensitive to both vancomycin and gentamicin, vancomycin should be used in view of the documented neurotoxicity seen with gentamicin. When gentamicin resistance occurs, amikacin and tobramycin are appropriate alternatives. The high risk of epilepsy with the penicillins and cephalosporins makes them less suited for IVT therapy, although the newer cephalosporins have some promise for IVT therapy. CNS fungal infections can be treated effectively with IVT amphotericin B but with a high risk of significant toxicity. Miconazole appears to be safer than amphotericin B but there is less clinical experience with this drug. Table 1 summarizes the dosages, indications, and toxicity of those antibiotics commonly used for intraventricular administration, which have been reported previously.