[Brain abscess. The experience of 30 years].

Background and Objective: The aim of this study was to evaluate epidemiological and clinical aspects of brain abscess (BA) and changes in clinical patterns during the last 30 years.
Patients and Method: Observational study of a cohort of non-pediatric patients with BA admitted at a 944-bed hospital. Data collection from clinical records was done according to a standard protocol. We analysed epidemiological, clinical and microbiological data and localization as well as changes during a 30 year period divided in 2 equal length phases: 1976-1989 (P1), and 1990-2005 (P2).
Results: 108 patients with BA were included (mean age: 45 years; range: 12-86; > 40 years in 42.4% P1, and 71.4% in P2, p < 0.05); 66 patients were treated in P1 and 42 in P2 (annual incidence: 4-5 cases and 2-3 cases per 10(6) population in P1 and P2, respectively). A predisposing condition was identified in 86% cases with statistically significant differences (p < 0.05) in: otitis media (18.2% vs 2.4%); dental infection (3% vs 16.7%); penetrating cranial trauma (16.7% vs 0%); post-neurosurgery (15.1% vs 21.4%), in P1 and P2, respectively; microbiologic diagnosis was made in 76% (no statistical differences P1/P2). Clinical aspects statistically different in P1/P2: severely altered mental status (10.6% vs 0%); vomiting (37.9% vs 21.4%); focal neurological deficits (37.9% vs 71.4%). No statistically significant differences were found in other epidemiological, clinical, radiological, microbiological or outcome characteristics in P1/P2.
Conclusions: In spite of a lower incidence in P2 and certain epidemiological and clinical differences in P1/P2, mortality and relapses rates have not significantly changed in a 30 year period.