Intracranial Subdural Abscess Caused by Actinomyces meyeri Related to Dental Treatment: A Case Report

Intracranial subdural abscess is a rare condition. Although brain abscess is often reported in relation to dental infection, reports of intracranial subdural abscess are few. Actinomyces spp. forms part of the normal flora of the oral, gastrointestinal, and genital tract, and is rarely the cause of intracranial infection; moreover, the pathogen Actinomyces meyeri is very rare. We report an exceptional case of intracranial subdural abscess caused by A. meyeri and related to dental treatment. A 57-year-old woman initially presented with a 5-day history of headache. Because left arm numbness and weakness became apparent, she was admitted to our department. She had a history of hypertension and dental problems requiring tooth extractions. Diffusion-weighted imaging (DWI) showed a 1-cm right convexity hyperintense mass above the postcentral gyrus. A post-gadolinium T1-weighted image showed a thin hypointense area with peripheral rim enhancement in the right subdural space that appeared to partially thicken in the same location as the DWI-positive mass. She underwent emergent navigation-guided drainage and 4 mL of pus was obtained. Postoperatively, left arm numbness and weakness disappeared. Cultures showed growth of A. meyeri and Fusobacterium nucleatum. She was started on intravenous penicillin G and metronidazole. After a 4-week course of the intravenous antibiotics, her headache gradually improved and the abscess in the subdural space subsided. To our best knowledge this is the first case report of intracranial subdural abscess caused by A. meyeri associated with dental treatment.