Intracranial abscesses: changes in epidemiology and management over five decades in Merseyside.

BACKGROUND: To review the changing patterns in incidence, etiology, management, morbidity, and mortality for intracranial abscesses over the last decade and compare them with two previous studies spanning four decades, conducted at the regional neurological surgical unit on Merseyside.

PATIENTS AND METHODS: A retrospective review of case notes and laboratory records of all cases of intracranial abscess admitted to the regional neurosurgical unit between January 1995 and January 2005 was performed.

RESULTS: Forty-seven cases of intracranial abscesses were identified. The incidence of these, in our study, was an average of five cases per year as opposed to eight cases per year in the previous decades. The mean age at presentation was 46 years, and the male-to-female ratio was 4:1. Diagnosis by computerized tomography scan was performed in majority of patients (85.1%) within 48 h of presentation. The incidence of otogenic abscess was 12.8% (6/47), much lower than that seen in previous decades. An association with previous neurosurgical procedures was noted in 19.1% of cases, similar to that seen in the previous decade. In 73.4% (36/49) of samples, organisms were isolated. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated from two patients (4.3%); an isolate not reported in the previous two studies. Nine patients (19.1%) died during their hospital stay as compared to the overall mortality of 43%and 24%seen in the earlier reviews. Of the 38 who survived, 47.3% had a good outcome at discharge.

CONCLUSIONS: In comparison with the two previous studies, the overall incidence of intracranial abscesses is decreasing on Merseyside. Moreover, the predisposing factors for intracranial abscesses have changed over the decades. The number of otogenic cases has declined. The incidence of brain abscesses following neurosurgical procedures is still a major cause for concern, as is the emergence of MRSA, as a significant pathogen.