Do brain abscesses have a higher incidence of odontogenic origin than previously thought?

Objective. The aim of this study was to answer the following clinical question: "In patients admitted to a tertiary care hospital with a diagnosis of brain abscess, how common is odontogenic etiology?" Study Design. We designed a retrospective study of patients with brain abscesses diagnosed at the Massachusetts General Hospital between 1980 and 2017. Inclusion criteria were complete medical records outlining clinical course, relevant dental history, and radiographic and microbiologic data. Results. Of 167 intracranial abscesses, 88 (52.7%) originated from a head/neck source, and 12 (13.6%) were of odontogenic etiology. Dental radiographs in 7 cases showed active dental infection. The remaining 5 patients reported recent dental procedures. Frontal lobe localization was the most common (7 of 12 [58.3%]). Presenting signs included headache (66.7%), mental status changes (41.6%), visual deficits (41.6%), and speech difficulties (33.3%). Computed tomography (CT) or magnetic resonance imaging (MRI) confirmed all diagnoses. Drainage via open craniotomy was performed in 6 (50%) of 12 patients, and stereotactic CT-guided drainage in 4 (33.3%). The most common pathogens were Streptococcus milleri (45.5%), Staphylococcus species (27.3%), and Fusobacterium (27.3%). All cases had favorable outcomes. Five had residual neurologic deficits, 4 had persistent visual complaints, and a recurrent abscess developed in 1 case. Conclusions. These findings showed a higher subset (13.6%) of brain abscesses that could be attributed to odontogenic etiology than previously reported in the literature and highlight the need to rule out dental sources in cryptogenic cases.