Prophylactic Antibiotics in Patients with Traumatic Pneumocephalus or Cerebrospinal Fluid Leak

Introduction Pneumocephalus and cerebrospinal fluid (CSF) leaks are uncommon after trauma, but they expose the sterile CSF to environmental pathogens and create theoretical risk of central nervous system infection (CNSI). Prophylactic antibiotics are commonly given to these patients, but there is a paucity of evidence to guide this practice. We aim to quantify the incidences of these entities and analyze the efficacy of prophylactic antibiotics in preventing CNSIs. Methods A retrospective cohort study was conducted using our institutional trauma registry. All patients admitted from January 2014 to July 2020 with traumatic pneumocephalus (TP) or basilar skull fracture with CSF leak (BSF-CSF) were included. ICD-9 and ICD-10 codes were used to identify CNSIs. CNSI rates among defined prophylactic antibiotic regimens, no antibiotics, and other antibiotic regimens were evaluated. ANOVA was used to analyze differences between the groups. Results 365 patients met inclusion criteria: 360 with TP; 5 with BSF-CSF. 1.1% (4/365) of patients developed CNSI, all with isolated traumatic pneumocephalus. 1.4% of patients (1/72) without antibiotics; 1.2% (3/249) receiving IV antibiotics outside of a defined regimen; and 1.1% (1/88) on a designated prophylactic regimen developed CNSIs. ANOVA indicated the incidence of CNSI was not significantly different among patients who received antibiotics or not, regardless of the regimen (p-value 0.958). Conclusion TP and BSF-CSF are rare diagnoses among trauma patients. The rate of CNSI is marginal and antibiotics do not appear to confer a protective advantage. A larger trial is needed to elucidate the true effect of antibiotics on preventing CNSIs in patients with these uncommon diagnoses.