TiHo Bibliothek elib - Tierärztliche Hochschule Hannover

Falldarstellung
In an intact B-CSF-B and BBB, large, complex molecules have limited penetrance
while during inflammatory conditions entry may be enhanced. For example betalactam
antibiotics are ionized at normal pH. An inflammatory process promotes an
acidic enviroment which increases the plasma- CSF pH gradient and molecules can
cross membrane barriers efficiently (Maddison et al 2008) to reach therapeutic levels
within the CNS. Bypassing the B-CSF-B and BBB to deliver drugs directly to the CSF
with an external ventricular drain has been considered in human medicine cases.
Raza et al. (2005) reports that insertion of an external ventricular drain (EVD) solely
for antibiotic therapy might be justified in cases where the organisms are sensitive
only to antibiotics with poor CNS penetration, an increase in the antibiotic dose is
precluded by its toxicity, or where IV therapy alone has not been clinically effective
(Raza et al. 2005). However, this procedure is not commonly performed in veterinary
medicine. Intraventricular injection of β-lactam antibiotics is not indicated in spite of
their poor CSF penetration due to the pro-convulsive activity of this antibiotic class,
but systemic dose of β-lactam antibiotics can be increased to ensure higher CSF
concentrations (Nau et al. 2010).
Several studies with animal meningitis models have demonstrated the effectiveness
of using systemic ampicillin with the addition of sulbactam or other β-lactamase
inhibitors (Jimenez-Mejias 1997; Cawley et al. 2002).
In this case study, ampicillin with sulbactam was also used effectively in a
concentration of 22 mg/kg IV every 6 hours. It was continued in the form of
amoxicillin clavulanic acid (21.5mg/kg, PO, q 12 hrs) for two weeks. Third- and
fourth-generation cephalosporins are better able to penetrate the BBB and can
achieve good therapeutic concentration (Tessier et al. 2010). Their spectrum varies.
Third generation cephalosporins such as cefovecin have a decreased gram positive
and increased gram- negative activity (Maddison et al. 2008). Cefovecin is reported
to be effective against Staphylococcus intermedius, β-hemolytic streptococci and
Pasteurella multocida (Maddison et al. 2008). Additionally. cefovecin appears
effective against anaerobes (Ramsey 2008).
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