Researchers at the University of Amsterdam, the Netherlands, evaluated the occurrence, treatment, and outcome of subdural empyema as a complication of community-acquired bacterial meningitis in 28 (2.7%) adults. Predisposing conditions in 26 (93%) patients included spread of otitis or sinusitis to the subdural space in 21 (75%). Presenting symptoms in 23 patients (82%) were neurologic and consisted of paresis, focal seizures, and dysesthesia contralateral to the empyema. The organism cultured from the CSF was Streptococus pneumoniae in 26 patients (93%) and Streptococcus pyogenes in 1 (3%). One patient had negative CSF cultures. Complications leading to an unfavorable outcome in 68% cases were seizures (50%), focal neurological abnormalities (54%), and hearing impairment (39%). Five patients with empyema causing midline shift were treated by neurosurgical evacuation of the empyema. 
COMMENT. Symptoms or signs indicative of subdural empyema in adults with meningitis are otitis or sinusitis, focal neurologic deficits, or seizures. In patients suspected of having developed subdural empyema, the diagnosis was confirmed by MRI with diffusion-weighted imaging. Lumbar puncture may be associated with a risk of brain shift and sudden clinical deterioration and requires careful monitoring.
In a pediatric study of intracranial empyema at the University of Paris Descartes, 33 of 38 patients presented with subdural empyema and 5 with extradural empyema. Ten were infants <1year of age, all related to bacterial meningitis, and 28 were children mainly associated with otitis or sinusitis infections. In children with subdural empyema, factors associated with poor prognosis were neurological deficit and cerebral herniation on admission CT scan.