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

Abstract

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.

Figure 1

(A) Contrast-enhanced CT revealed a large hypodense lesion with rim enhancement in the left cerebral hemisphere indicating the presence of an SDE. (B) Contrast-enhanced MRI showed a reduction of the SDE after burr hole drainage. (C) Serial follow-up contrast-enhanced MRI revealed an enlargement of the SDE with midline shifting 3 weeks after burr hold drainage. (D) Purulent pus was discharged after opening the thick outer capsule wall. (E) A small portion of the inner capsule wall that was strongly adherent to the cerebral cortex was not disturbed, in order to avoid damaging the cortex. (F) A CT at 12 months after removal of abscess demonstrated no recurred lesion. CT = computed tomography, MRI = magnetic resonance imaging, SDE = subdural empyema.

Figure 2

(A) Contrast-enhanced MRI revealed an SDE with diffuse leptomeningitis in the right cerebral hemisphere. (B) Thick and yellowish capsule with evidence of prior burr hole drainage was observed after dural incision. (C) After the thick outer capsule was removed, purulent and yellowish pus was observed. (D) A follow-up contrast-enhanced MRI 12 months after removal of the abscess revealed no remaining lesion or abnormal signals. MRI = magnetic resonance imaging, SDE = subdural empyema.

Figure 3

(A) Contrast-enhanced MRI revealed an SDE with diffuse leptomeningitis and adjacent osteomyelitis in the left parietal convexity. (B) DWI showed high signal intensity in the same region. (C) Purulent pus was discharged after opening the thick outer capsule wall. (D) The inner capsule wall that was strongly adherent to the cerebral cortex was left undisturbed, in order to avoid damaging the cortex. (E) Contrast-enhanced CT at 12 months post-craniotomy demonstrated no recurrent lesion, with improved leptomeningitis. CT = computed tomography, DWI = diffusion weighted imaging, MRI = magnetic resonance imaging, SDE = subdural empyema.