Cerebrospinal fluid antibiotic levels during treatment of shunt infections

Twenty patients with documented cerebrospinal fluid shunt infections were treated with daily intraventricular injections of methicillin, cephalothin, or gentamicin without removal of the shunt or external ventricular drainage. Periodic determinations of intraventricular antibiotic concentration revealed significant levels in relation to the established minimum inhibitory concentration in all cases.

Antibiotic prophylaxis in ventricular shunt surgery. II. Antibiotic concentrations in cerebrospinal fluid

Investigation of cerebrospinal fluid (CSF) antibiotic levels from patients operated upon under short-term prophylactic protocols for shunt insertions or revisions revealed low-level CSF penetration by nafcillin and virtually no methicillin activity. Nafcillin levels were not influenced by route of injection or CSF sampling time, but were inversely proportional to ventricular size. The authors recommend nafcillin over methicillin as the preferred prophylactic agent in shunt surgery. Although the 25 mg/kg preoperative dose may be adequate for reducing infection risk, higher dosages should be considered when the ventricles are markedly dilated.

Cerebrospinal fluid antibiotic concentrations in ventricular shunt infections

The concentration of antibiotic in cerebrospinal fluid was measured during treatment of seven children with infected ventricular shunts. Antibiotics were administered via the ventricular shunt or through an external ventricular drain. 53 CSF samples were obtained 7-19 h after antibiotic administration. Wide variation in cerebrospinal fluid antibiotic concentration occurred from patient to patient following either route of administration. For optimal management of shunt infections, we recommend periodic assessment of antibiotic concentration or activity in ventricular fluid and determination of the minimum inhibitory concentration of antibiotic required for each pathogen.

[Methicillin penetration into the cerebrospinal fluid of patients]

Penetration of methicillin through the blood-liquor barrier in neurosurgical patients was studied. When administered in a dose of 2 gm the drug penetrated through the barrier in 1/3 of all observations within 1 to 3 hours. Increased liquor pressure in the patients resulted in prolongation of the antibiotic effect in the cerebrospinal fluid. The methicillin levels in the liquor were no sufficient for the growth inhibition of most methicillin sensitive staphylococci.

Nafcillin treatment of Staphylococcus aureus meningitis

Serial serum and cerebrospinal fluid nafcillin concentrations were determined in a patient successfully treated with nafcillin (200 mg/kg per day) for Staphylococcus aureus bacteremia and meningitis. Nafcillin and methicillin cerebrospinal fluid concentrations were compared.