Non-traumatic brain abscess. Epidemiology, clinical symptoms and therapeutic results.

Two groups of patients with non-traumatic focal intracranial suppurative diseases were studied retrospectively to illustrate epidemiology, clinical symptoms and therapeutic results. The first group consists of 87 patients treated for brain abscess in the Department of Neurosurgery in Lund. During the 36-year period investigated (1947-1982) marked epidemiological changes occurred. Thus otogenic abscesses, constituting 33% of the cases below the age of 30 during the first 12 years of the study, virtually disappeared. During the third 12-year period of this study a marked increase in the number of abscesses was noted. The increase was caused particularly by the number of cryptogenic abscesses amounting to 51% of the material during 1971-1982. The second group of patients consists of all patients with pre- or post-mortem diagnosed brain abscess in the city of Malmö during 1960-1981. Since during this period 85% of all persons who died in this city were subjected to post-mortem examination this material offers a unique possibility of epidemiological studies. The combined study of these two groups of patients lends no support to the view that a real increase in the number of brain abscesses has occurred. We conclude that in patients with cryptogenic brain abscess the clinical symptoms do not usually indicate the presence of an infectious disease. In the majority of these patients a correct diagnosis has presumably not been obtained until the last decade. Furthermore, the investigation confirms the view that a mortality below 10% is nowadays feasible in unselected cases of brain abscess.