Intracranial abscesses over the last four decades; changes in aetiology, diagnostics, treatment and outcome.

Background The development of modern medicine has resulted in changes in the predisposing conditions, clinical picture, treatment and results of treatment of intracranial abscesses. This study sought to evaluate these changes in a hospital district. Methods A retrospective analysis of the clinical data of all patients treated due to intracranial abscesses at a tertiary referral centre, between 1970-2012. Results The total number of intracranial abscesses was 166. The incidence of intracranial abscesses was 0.33/100 000/year (2000-2012). The most common predisposing conditions were infection of the ear-, nose- and throat region (22%), odontogenic infection (15%) and cardiac anomaly (13%). Lately (2000-2012), infections of the ear-, nose- and throat region (15%) and cardiac anomalies (5%) have become less common, whereas odontogenic infections (32%) have become more common. The most common pathogens belong to Streptococcus spp (42%), Fusobacteriae (14%), Actinomycetales (8%) and Staphylococcus spp (8%). Most patients (66%) experienced a favourable recovery; the proportion of patients with favourable outcome enabling return to prior occupation rose over time, from 12% in 1970-1989 to 24% in 1990-2012. Conclusions The predisposing conditions for intracranial abscesses have changed markedly within the study period. Odontogenic infections have become a common predisposing condition, whereas infections of the ear-, nose- and throat region and cardiac malformations are nowadays less common as predisposing conditions compared to at the beginning of the study period. The proportion of patients with favourable outcome enabling return to prior occupation seems to have increased with time.