- Suppurative infection involving the brain parenchyma
- May be a single or multiple lesions
- Males more commonly affected (2:1 male-to-female predominance)
- Typical age of presentation is 4 to 7 years but varies according to predisposing factor.
- 85% of cases have a predisposing risk factor.
~1,500 to 2,500 cases (adults and pediatric combined) occur per year with up to 25% being children.
- Cyanotic congenital heart disease (tetralogy of Fallot is most common)
- Otorhinolaryngologic infections such as sinusitis, mastoiditis, and chronic otitis media
- Meningitis (especially in neonates)
- Penetrating head trauma
- Surgical manipulation of the brain (ventriculoperitoneal shunts, tumor removal)
- Congenital lesions of the head and neck
- Cystic fibrosis
- Dental infections
- Lung infections
- Patients who have traveled to endemic areas where neurocysticercosis (Latin America, parts of Africa, Asia, and the Indian subcontinent) is endemic
- Immunocompromised patients (congenital or acquired)
- During recreational activities, wearing helmets may prevent penetrating head trauma.
- Appropriate management of acute otitis media and acute sinusitis as well as timely recognition of treatment failure
- Microorganisms enter the brain parenchyma by contiguous or hematogenous extension.
- Location of brain abscesses:
- Cyanotic congenital heart disease patients tend to have abscesses within the middle meningeal artery distribution: frontal, parietal, and temporal lobes.
- Frontal abscesses are commonly seen with sinus and dental infections.
- Temporal, parietal, or cerebellar abscesses tend to occur with mastoiditis or otitis media.
- Brain abscesses can occur anywhere in the brain parenchyma, regardless of a predisposing risk factor, secondary to hematogenous metastasis.
- Bacteria are the most common causes.
- Streptococcus milleri (anginosus) group and Staphylococcus spp. are the most commonly cultured microorganisms.
- Neonates may develop brain abscesses as a complication of gram-negative meningitis (Proteus, Citrobacter, Enterobacter, and Cronobacter species).
- Polymicrobial infections occur in 30–50% of cases.
- Anaerobic organisms are found with increasing incidence with improved laboratory and culture techniques. Common pathogens include Bacteroides, Peptostreptococcus, Fusobacterium, Propionibacterium, Actinomyces, Veillonella, and Prevotella.
- Neurocysticercosis is caused by the parasite, Taenia solium. Fungi and protozoa can cause brain abscess in immunocompromised patients.
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