Antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures

Basilar skull fractures (BSF) predispose patients to meningitis because of the possible direct contact of bacteria in the paranasal sinuses, nasopharynx or middle ear with the central nervous system (CNS). Cerebrospinal fluid (CSF) leakage has been associated with a greater risk of contracting meningitis. Antibiotics are often given prophylactically, although their role in preventing bacterial meningitis is not established.

To evaluate the effectiveness of prophylactic antibiotics for preventing meningitis in patients with BSF.

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, MEDLINE (1966 to February 2011), EMBASE (1974 to February 2011) and LILACS (1982 to February 2011). We also performed an electronic search of meeting proceedings from the American Association of Neurological Surgeons (1997 to September 2005) and handsearched the abstracts of meeting proceedings of the European Association of Neurosurgical Societies (1995, 1999 and 2003).

Randomised controlled trials (RCTs) comparing any antibiotic versus placebo or no intervention. We also identified non-RCTs to perform a separate meta-analysis to compare results.

At least two authors independently appraised trial quality and extracted data for each trial.

We identified five RCTs and 17 non-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention in patients with BSF. Most trials presented insufficient methodological detail. All studies included meningitis in their primary outcome. Overall, we evaluated 208 participants from the five RCTs that were considered suitable for inclusion in the meta-analysis. There were no significant differences between antibiotic prophylaxis groups and control groups in terms of reduction of the frequency of meningitis, all-cause mortality, meningitis-related mortality, and need for surgical correction in patients with CSF leakage. There were no reported adverse effects of antibiotic administration, although one of the five RCTs reported an induced change in the posterior nasopharyngeal flora towards potentially more pathogenic organisms resistant to the antibiotic regimen used in prophylaxis. We performed a subgroup analysis to evaluate the primary outcome in patients with and without CSF leakage. We also completed a meta-analysis of all the identified controlled non-RCTs (enrolling a total of 2168 patients), producing results consistent with the randomised data.

Currently available evidence from RCTs does not support prophylactic antibiotic use in patients with BSF, whether there is evidence of CSF leakage or not. Until more research is completed, the effectiveness of antibiotics in patients with BSF cannot be determined because studies published to date are flawed by biases. Large, appropriately designed RCTs are needed.