Subdural empyema complicating bacterial meningitis in a child: enhancement of membranes with gadolinium on magnetic resonance imaging in a patient without enhancement on computed tomography.

Subdural empyema is a known yet infrequent complication of bacterial meningitis. Subdural effusions occur frequently with meningitis in children and usually resolve spontaneously or with subdural taps. Subdural empyema should be suspected when a patient fails to respond to antibiotic therapy or worsens neurologically. Computed tomography (CT) scans with contrast often show enhancement of subdural collections when an empyema exists. However, this is not true all of the time. We present a case of subdural empyema complicating bacterial meningitis in a 4 month old in which CT enhancement was not present yet magnetic resonance imaging (MRI) scans with gadolinium demonstrated intense enhancement. For comparison, we present a second case of a child with sterile subdural effusions due to meningitis that demonstrates an absence of contrast enhancement on MRI studies. MRI scans with contrast may offer a more sensitive means of making an early diagnosis of subdural empyema.