Multidisciplinary Management of Odontogenic Brain Abscess Caused by Mixed Anaerobic Infection: A Case Report

Abstract

Introduction: Odontogenic brain abscess is an uncommon but potentially fatal intracranial infection, and its diagnosis is often delayed because of nonspecific symptoms and difficulty identifying the primary source of infection. Microbiological confirmation of oral pathogens is rare, particularly in anaerobic infections. Case Presentation: A 66-year-old man was admitted with dizziness, headache, and progressive right-sided weakness. Brain magnetic resonance imaging (MRI) revealed a left parietal abscess with surrounding edema. Cerebrospinal fluid (CSF) analysis showed marked inflammatory changes, whereas routine cultures were negative. Metagenomic next-generation sequencing (mNGS) of the CSF identified Porphyromonas gingivalis, Fusobacterium nucleatum, and Actinomyces israelii. An oral examination revealed severe periodontal disease, supporting an odontogenic source. Despite broad-spectrum antimicrobial therapy, the abscess ruptured into the ventricular system. The patient was successfully treated with targeted antibiotics combined with ventricular drainage and intraventricular lavage, resulting in substantial neurological recovery. No recurrence was observed during 6 months of follow-up. Conclusions: This case provides direct microbiological evidence linking chronic periodontal disease to brain abscess formation and highlights the diagnostic utility of CSF mNGS for identifying anaerobic odontogenic pathogens. Early recognition of oral infection as a potential source, and timely multidisciplinary intervention, are critical for improving outcomes in patients with high-risk brain abscesses.