Central Nervous System Infections

University of Pennsylvania Medical Center Guidelines for Antibiotic Use

CENTRAL NERVOUS SYSTEM INFECTIONS

Clinical Setting	Empiric Treatment	Likely Pathogens	Definitive Treatment	Dosage Regimen	Duration
Meningitis
Community- acquired	18-50 yr. old ceftriaxone ± vancomycin¹	S. pneumoniae	If MIC <=0.1: penicillin G	12-20mu/d IV in 6 divided doses	10-14 days
		S. pneumoniae	If MIC >0.1:¹ ceftriaxone	2gm IV q 12 hour
		N. meningitidis	ceftriaxone	2gm IV q 12 hour
		H. influenzae	ceftriaxone	2gm IV q 12 hour
Community- acquired	>50 yr. old ampicillin + ceftriaxone ± vancomycin¹	as above	as above	as above	10-14 days
		L. monocytogenes²	ampicillin ± gentamicin	2gm IV q 4 hour consult pharmacokinetics service
		gram negative bacilli	ceftriaxone (cefepime: if P. aeruginosa)	2gm IV q 12 hour 2gm IV q 8 hour
Post- surgical	meropenem⁷ + vancomycin	S. aureus	nafcillin³ ± intraventricular vancomycin⁵	2gm IV q 4 hour	14 days
		coagulase negative staphylococcus	vancomycin ± intraventricular vancomycin⁵	consult dosing information at this link
		acinetobacter	imipenem	consult dosing information at this link
		other gram negative bacilli	ceftriaxone⁴ ± intraventricular gentamicin⁶ (cefepime ± intraventricular gentamicin if P. aeruginosa)	2gm IV q 12 hour 2gm IV q 8 hour
Brain Abscess	ceftriaxone + metronidazole	upper respiratory flora	ceftriaxone +	2gm IV q 12 hour	Until resolved
			metronidazole	500mg IV/PO q 12 hour
			(nafcillin³ if S. aureus)	2gm IV q 4 hour

¹Several cases of ceftriaxone resistant pneumoccoci have been reported. Vancomycin dosing for pneumococcal meningitis has not been studied in detail but some authorities recommend the use of 30-45mg/kg/d for meningitis, given 8-12 hourly (10-15 mg/kg/8h) with maximum doses of 2 to 3g/d (700 to 1000 mg q 8h) with normal renal function. Vancomycin should be stopped if the pneumococcus is not penicillin resistant. Consult pharmacokinetics.

²Risk factors for L. monocytogenes: age > 50 years, HIV and other immunosuppressive states, pregnancy

³If beta-lactam allergy use trimethoprim/sulfamethoxazole; if MRSA-use vancomycin

⁴If organism is ceftriaxone susceptible

⁵ The dosage for intraventricular vancomycin is 10-20 mg once daily every 1 to 3 days until clinical and microbiologic improvement occurs.

⁶The dosage for intraventricular gentamicin is 5-10 mg once daily every 1 to 3 days until clinical and microbiologic improvement occurs. The gentamicin must be preservative free. Amikacin can be used in place of gentamicin at the same dosage, in case of gentamicin resistance.

⁷The dosage for meropenem is 2g IV q 8H, with modifications made for abnormal renal function

modified 11/21/04 by Paul Edelstein

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