Long-term Mortality and Risk of Epilepsy in Children and Young Adults With Brain Abscess

Background: The long-term prognosis of brain abscess is unclear. Methods: Using nationwide, population-based medical registries, we included all individuals <20 years of age hospitalized with first-time diagnosis of brain abscess in Denmark from 1982 to 2016. A comparison cohort individually matched for age, sex and residence was identified, as were siblings of all study participants. Next, cumulative incidence curves of mortality and new-onset epilepsy were constructed, and Cox regression was used for analyses of hazard rate ratios (HRRs) with 95% confidence intervals. Results: We identified 155 brain abscess patients and 1,550 population controls with median follow-up times of 15 years (interquartile range, 6-25) and 16 years (interquartile range, 11-26). Ear-nose-throat infections (22%) and congenital heart disease (13%) were the most common predisposing conditions for brain abscess. Overall mortality was 21/155 (14%) in brain abscess patients versus 20/1,550 (1%) in population controls. The corresponding HRRs were 150 (95% confidence interval: 19.8-1,116) after 1 year of observation, 24.6 (4.78-127) after 2-5 years and 0.66 (0.09-4.98) after 6-30 years. New-onset epilepsy occurred in 28% of 30-day brain abscess survivors versus 1% in population controls yielding a HRR of 29.6 (14.4-60.8) adjusted for previous head trauma, stroke and cancer. Analyses of sibling cohorts showed that family-related factors did not explain the observed increased risks of death or epilepsy among brain abscess patients. Conclusions: Brain abscess is associated with increased risk of mortality for up to 5 years. New-onset epilepsy occurred in 28% of survivors and remained a risk for several years after infection.