Clinical characteristics and prognostic factors in brain abscess

Brain abscess remains a serious intracranial infection associated with substantial mortality and neurological disability, despite advances in neuroimaging, neurosurgery, and antimicrobial therapy. Recent data from the Middle East are limited, and the prognostic impact of readily available clinical and radiologic variables in this region remains poorly defined.

We retrospectively analyzed data from consecutive patients with radiologically and clinically confirmed brain abscesses treated at two tertiary centers in Jeddah, Saudi Arabia, between 2010 and 2020. Demographic, clinical, radiological, and laboratory data were extracted from medical records using a standardized form. Functional outcomes at discharge were assessed using the modified Rankin Scale (mRS) and dichotomized as favorable (mRS 0-3) or unfavorable (mRS 4-6).

Thirty-four patients were included (mean age 30.9 years, standard deviation [SD] 21.0; 70.6% male). Single abscesses predominated (94.1%), most commonly located in the frontal (35.3%) and parietal (29.4%) lobes, with a mean abscess volume of 33.5 mL (SD 29.9). Microbiological yield was 44.1% overall; Group B Streptococcus was the most common organism identified in aspirate cultures (5/12 positive aspirates), and coagulase-negative Staphylococci predominated in positive blood cultures (3/6). At discharge, 24 (70.6%) patients had a favorable outcome, and 10 (29.4%) patients had an unfavorable outcome. Patients with favorable outcomes were younger than those with unfavorable outcomes (mean 25.4 vs. 44.0 years; P = 0.016), and age ≤30 years was significantly associated with favorable outcomes (P = 0.019). Lower Glasgow Coma Scale (GCS) at admission, particularly GCS <8, was strongly associated with unfavorable outcomes (P = 0.015). Abscess volume, lobar location, sex, nationality, and diabetes were not significantly related to outcomes.

In this two-center Saudi cohort, approximately two-thirds of patients with brain abscess achieved favorable functional outcomes, comparable to those in recent international series. Older age and reduced level of consciousness at admission were the main variables associated with poor outcomes on univariable analysis, whereas abscess volume and location were not significant in this sample. These findings support the central role of simple bedside variables, age and admission GCS, in risk stratification and highlight the need for larger regional studies to validate prognostic models and evaluate long-term outcomes in Middle Eastern populations.