Unusual subdural empyema in a homeless patient diagnosed by molecular approach: a case report

BACKGROUND: We report a case of subdural empyema in a homeless patient caused by Bartonella quintana. B. quintana is a facultative intracellular bacteria for which bacterial growth is fastidious. The molecular biology approach has been a real help in establishing the diagnosis. CASE REPORT: A 59-years old homeless patient, with a history of chronic alcohol abuse, was brought to the emergency department with a massive subdural empyema. Extensive microbiological evaluation didn’t reveal any pathogen in the pus collected before antibiotic treatment. B. quintana was detected in the pus from the empyema using a 16S rRNA-based PCR. Histology of intraoperative samples was consistent with the diagnosis and a serological assay was positive. The patient responded well to a treatment that included craniectomy with drainage of the loculated pus, total removal of the infected capsule and a combination of antibiotics. CONCLUSION: This unique case of B. quintana-related empyema illustrates the risk of secondary infection of subdural hematoma with B. quintana since such infections have recently reemerged, predominantly among the homeless populations. Patients with subdural empyema in at-risk populations should be systematically evaluated for B. quintana with an appropriate diagnostic approach involving molecular biology.