Bacterial Abscess, Cerebral

Abstract

Brain abscess is a focal, suppurative process within the brain parenchyma that begins in an area of cerebritis or devitalized brain tissue due to hypoxia, ischemia, or infarction and develops into a collection of pus surrounded by a well-vascularized capsule. A brain abscess may arise from a contiguous cranial infection, such as chronic otitis media or a frontoethmoidal sinusitis, or from hematogenous spread of infection from a remote site. The majority of brain abscesses that arise from a contiguous infection are solitary, whereas those that arise from hematogenous spread of infection tend to be multiple. Penetrating craniocerebral trauma or a neurosurgical procedure can also be the cause of a brain abscess. A brain abscess presents as an expanding intracranial mass lesion rather than as an infectious process. The most common symptom is headache, occurring in >75% of patients. Fever is present in only 50% of patients at presentation, but >60% have a focal neurological deficit. Seizures occur in 25–40% of patients. The diagnosis of a brain abscess is made by neuroimaging with magnetic resonance imaging (MRI) being more sensitive than computed tomography (CT). MRI is better able to demonstrate an abscess in the early cerebritis stage than CT. The specific etiological organism is identified by Gram's stain and the culture of brain abscess pus obtained by stereotactic CT-guided aspiration and drainage. A 6–8 week course of intravenous antimicrobial therapy is followed by a 2–3 month course of oral antimicrobial therapy.