Uncommon, serious, life-threatening infections
They include brain abscess and subdural or extradural empyema and are classified according to the anatomical location or the etiologic agent.
The term brain abscess is used in this article to represent all types of intracranial abscesses
An intracranial abscess is an accumulation of pus and other matter within the skull.
Depending on the location of the abscess and the severity of inflammation and swelling, pressure against the brain may cause mild or severe neurologic symptoms, coma, or death.
Before the emergence of the AIDS pandemic, the frequency of brain abscesses were estimated to account for 1 per 10,000 hospital admissions, or 1500-2500 cases annually.
The prevalence of brain abscess in patients with AIDS is higher, so the overall rate has thus increased. The frequency of fungal brain abscess has increased because of the frequent administration of broad-spectrum antimicrobials, immunosuppressive agents, and corticosteroids.
Early diagnosis and treatment are key to survival.
Infections of the brain and skull may be caused by a number of different bacteria, in a single strain or mixed, originating within the body, in dental or sinus infections, in chronic or traumatic wounds, or from foreign matter.
Viruses, fungi, parasites, protozoa, and other microbial organisms may also cause intracranial abscess.
With the introduction of antimicrobics and the increasing availability of imaging studies, such as CT scanning and MRI, the mortality rate has decreased to less than 5-15%.
Rupture of a brain abscess, however, is associated with a high mortality rate (up to 80%)
Children with congenital heart disease and people with compromised immune systems due to chronic disease, cancer therapy, HIV, AIDS, and immunosuppressive drugs after organ transplantation face higher risk.