Brain abscess

J.Sales-Llopis

Neurosurgery Service, Alicante University General Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL - FISABIO Foundation), Alicante, Spain.

A brain abscess is a focal area of necrosis starting in an area of cerebritis surrounded by a membrane.

Brain abscesses are suppurative infections of the brain parenchyma surrounded by a vascularized capsule.

see also Intracranial abscess.

It is a potentially life-threatening condition requiring prompt radiological identification and rapid treatment.

Brain abscess classification.

Brain abscess epidemiology.

see Brain abscess etiology.

Clinical presentation is non-specific, with many cases having no convincing inflammatory or septic symptoms.

Abscess formation should be considered in case of clinical deterioration, headache, and any neurological deficit after febrile episodes.

Similar to any other mass lesion but tend to progress rapidly.

Symptoms of raised intracranial pressure, seizures and focal neurological deficits are the most common forms of presentation

Eventually, many abscesses rupture into the ventricular system, which results in a sudden and dramatic worsening of the clinical presentation and often heralds a poor outcome.

Cerebral abscesses result from pathogens growing within the brain parenchyma. Initial parenchymal infection is known as cerebritis, which may progress into a cerebral abscess.

Cerebral infection is commonly divided into four stages with distinct imaging and histopathologic features:

early cerebritis (a focal infection without a capsule or pus formation,can resolve or develop into frank abscess) late cerebritis

early abscess/encapsulation - may occur 10 days after infection

late abscess/encapsulation - may occur >14 days after infection.

see Brain abscess diagnosis.

see Brain abscess differential diagnosis.

see Brain abscess treatment.

see Brain abscess management.

Brain abscess outcome.

Brain abscess case series.

see Brain abscess case reports.

Known space-occupying lesion, centered in the right frontal anterior white matter, with estimated diameters of 3.5 x 3 x 3.5 cm. It shows well-defined contours and a practically spherical shape. A predominantly hypointense signal on T1 and homogeneously hyperintense on T2, with a wall with hypointense behavior on T2-weighted sequences. After contrast administration, only enhancement of its wall was observed, in a fine and linear way, without identifying solid poles. The lesion shows diffusion sequence restriction and low values of rVSC in perfusion. Marked surrounding vasogenic edema, which causes a mass effect on the neighboring sulci, as well as mild subfalcian herniation, with a deviation from the midline of approximately 6 mm (significant improvement compared to previous CT control). The discrete mass effect is also on the knee of the corpus callosum and the frontal horn of the right ventricle. The findings are compatible with a brain abscess. A small solution of continuity is observed in its anterior wall, in contact with the meninge, which is thickened in a laminar manner in relation to inflammatory involvement, without clearly identifying empyema. Extensive occupation of the frontal sinus bilaterally, with an enhancement of its wall. Retrospectively, the CT study showed slight permeation on the posterior wall of one of the loculations of the frontal sinus close to the abscess. Small hyperintense foci in subcortical and periventricular white matter with a chronic ischemic profile of a small vessel, to a mild degree. Diagnostic impression: Findings compatible with a right frontal parenchymal abscess, 3.5 cm in diameter, with inflammatory changes and thickening of the adjacent pachymeninge, although without clear associated empyema.