[Brain abscess. Clinicomicrobiologic study and prognostic analysis of 59 cases]

Clinical, microbiological, therapeutic and prognostic characteristics of brain abscesses were analyzed as well as the influence of CT in their evolution.

Retrospective study of 59 patients with the diagnosis of brain abscess of bacterial source before (group A) and after (group B) the introduction of CT (25 and 34 patients, respectively).

The most common symptom was headache (76.3%) and the most common abnormality in physical examination was a decrease in the level of consciousness (61%) and this abnormality was associated with a higher mortality rate (13% versus 41.6%; p < 0.05) and also a higher proportion of neurologic sequelae (50% versus 85.7%; p < 0.05). The diagnosis was obtained earlier in group B. The hematogenous source predominated (32.2%); an adjacent source was identified in 28.8% and an apparent source was not recognized in 27.2% (40% in group A versus 17.6% in group B). Anaerobic and microaerophilic streptococci were the bacteria recovered most frequently. Gram-negative aerobic bacteria were the most common in otogenic abscesses. The use of corticosteroids had no influence upon mortality, but it was associated with a lower percentage of neurological sequelae (40% versus 14%; p < 0.05). The introduction of CT decreased mortality (40% in group A versus 23.5% in group B, although this difference was not significant) and also sequelae (86.6% in group A versus 57.6% in group B; p < 0.05). Leaving apart cases of bacterial endocarditis, in which death was due to the underlying heart disease and a systemic sepsis picture, mortality attributed to brain abscess was 20.3%.

The introduction of CT has meant a significant breakthrough for the diagnosis, treatment and follow-up of these patients and has contributed to improvement in survival. In our series, the diagnosis of brain abscess was obtained earlier and the number of brain abscesses with no apparent source has decreased since the introduction of CT. Moreover, CT sensitivity is really good for locating multiple abscesses. Overall, the prognosis of these patients has improved since the introduction of this technique. Nevertheless, brain abscess is still associated with a relevant morbi-mortality rate.