Review of 140 patients with brain abscess.

There were 140 cases of brain abscess treated between 1980 (when CT scanning became available) and June 1991. These arose by spread of a contiguous area of infection in 37%, and from another identified cause in 22%; the origin was undetermined in 41%. There were multiple abscesses in 11%. The abscess was < 2 cm in diameter in 21%. In two-thirds of the patients, the intracranial pressure was raised, there were localizing neurologic signs in 33%, and in 28% there were epileptic seizures. The computed tomographic (CT) feature of an abscess in the capsular stage was a thin, regular, and uniform, ring-like enhancement. In the cerebritis stage, nine out of 17 patients showed a uniform enhancement throughout the lesion. Since 1989, 14 cases have been investigated with magnetic resonance imaging (MRI). In 11, the abscess was in the capsular stage. In both T1- and T2-weighted images, the abscess and the surrounding inflammatory area were well demonstrated, and with T2-weighting, the capsule showed a low-intensity signal clearly. In the three abscesses in the cerebritis stage, there was a uniform abnormality with indistinct margins between the abscess, inflammatory edema, and surrounding grey and white matter. All cases received a combination of wide-spectrum antibiotics before the organism was identified; and later the medication was administered according to bacteriologic indication of the organism of 112 cases, organisms were identified in 71%, with anaerobic organisms occurring in 30% of these. In 127 cases, surgical treatment was used: either repeated aspiration, excision or both. We treated 13 cases that had small, early, or multiple abscesses with antibiotics only. The mortality with surgical treatment was 7.9%, and no case treated conservatively died.