Delayed intracranial subdural empyema following burr hole drainage: Case series and literature review.

Rationale: A subdural empyema (SDE) following burr hole drainage of a chronic subdural hematoma (CSDH) can be difficult to distinguish from a recurrence of the CSDH, especially when imaging data is limited to a computed tomography (CT) scan.
Patients Concerns: All patients underwent burr hole drainage of the CSDH at first, and the appearance of the SDE occurred within one month.
Diagnoses: A contrast-enhanced magnetic resonance imaging (MRI) scan, with diffusion-weighted imaging (DWI), revealed both the SDE and diffuse meningitis in all patients.
Interventions: In Case 1, because the patient was very young, burr hole drainage of the SDE, rather than craniotomy, was performed. However, subsequent craniotomy was required due to recurrence of the SDE. In Cases 2 and 3, an initial craniotomy was performed without burr hole drainage.
Outcomes: Symptoms improved for all patients, and each was discharged without any neurologic deficits or subsequent recurrence.
Lessons: Neurosurgeons should consider the possibility of infection if recurrence of CSDH occurs within 1 month following drainage of a subdural hematoma. A contrast-enhanced MRI with DWI should be performed to differentiate SDE from CSDH. In addition, surgical evacuation of the empyema via wide craniotomy is preferred to burr hole drainage.