Structural formula of ceftriaxone, one of the third-generation cefalosporin antibiotics recommended for the initial treatment of bacterial meningitis.
Empiric antibiotics must be started immediately, even before the results of the lumbar puncture and CSF analysis are known. The choice of initial treatment depends largely on the kind of bacteria that cause meningitis in a particular place. For instance, in the United Kingdom empirical treatment consists of a third-generation cefalosporin such as cefotaxime or ceftriaxone. In the USA, where resistance to cefalosporins is increasingly found in streptococci, addition of vancomycin to the initial treatment is recommended. Empirical therapy may be chosen on the basis of the age of the patient, whether the infection was preceded by head injury, whether the patient has undergone neurosurgery and whether or not a cerebral shunt is present. For instance, in young children and those over 50 years of age, as well as those who are immunocompromised, addition of ampicillin is recommended to cover Listeria monocytogenes. Once the Gram stain results become available, and the broad type of bacterial cause is known, it may be possible to change the antibiotics to those likely to deal with the presumed group of pathogens.
The results of the CSF culture generally take longer to become available (24-48 hours). Once they do, empiric therapy may be switched to specific antibiotic therapy targeted to the specific causative organism and its sensitivities to antibiotics. For an antibiotic to be effective in meningitis, it must not only be active against the pathogenic bacterium, but also reach the meninges in adequate quantities ; some antibiotics have inadequate penetrance and therefore have little use in meningitis. Most of the antibiotics used in meningitis have not been tested directly on meningitis patents in clinical trials. Rather, the relevant knowledge has mostly derived from laboratory studies in rabbits.
Adjuvant treatment with corticosteroids (usually dexamethasone) reduces rates of mortality, severe hearing loss and neurological damage in adults, specifically when the causative agent is Pneumococcus. The benefit of corticosteroids has been proven in adults as well as in children from high-income countries. Their use in children from low-income countries is not supported by evidence. Professional guidelines therefore recommend the commencement of dexamethasone or a similar corticosteroid just before the first dose of antibiotics is given, and continued for four days. Given that most of the benefit of the treatment is confined to those with pneumococcal meningitis, American guidelines suggest that dexamethasone be discontinued if another cause for meningitis is identified. In tuberculous meningitis, there is a strong evidence base for treatment with corticosteroids, although this evidence is restricted to those without AIDS.
The above information thankfully comes from the en.wikipedia.org at the following link.
