Brain abscess due to Fusobacterium necrophorum in a patient with convulsion and no signs of meningitis

Abstract

Here, we report brain abscess due to Fusobacterium necrophorum (F. necrophorum) in a 78-year-old healthy man. He developed convulsion and did not have any signs of meningitis. Although the brain magnetic resonance imaging findings of the left occipital lobe were typical of a brain abscess, his cerebrospinal fluid examination revealed only slight pleocytosis and mild increase in protein levels. Thus, it was difficult to rule out the possibility of metastatic brain tumor; the patient's condition was provisionally diagnosed as symptomatic epilepsy secondary to brain abscess. His convulsion disappeared soon after administration of antiepileptic, antibacterial, and steroid agents. A craniotomy was performed to evacuate the abscess, and F. necrophorum was identified by culturing the abscess ~contents. After the operation, he was treated with appropriate antibacterial agents, which resulted in resolution of the brain abscess. Although Fusobacterium species are gram-negative anaerobic bacilli commensal of the human oropharynx, we need to recognize that Fusobacterium species can be a primary pathogen causing brain abscesses and may leave residual neurological sequelae without early appropriate treatment.