Bilateral subdural empyema diagnosed after middle meningeal artery embolization: illustrative case.

backgroundMiddle meningeal artery (MMA) embolization has emerged as an effective adjunctive treatment for chronic subdural hematomas (SDHs) and is generally associated with a favorable safety profile. As utilization increases following recent randomized trials, uncommon complications are increasingly being recognized. The authors present a case of bilateral subdural empyema following bilateral MMA embolization. OBSERVATIONS: A 67-year-old man underwent bilateral MMA embolization for acute-on-chronic SDHs. Three weeks after an initially uncomplicated procedure, he developed progressive confusion, dysarthria, facial weakness, and hemiparesis. Serial CT and MRI demonstrated stable bilateral subdural collections without definitive radiographic evidence of empyema. Surgical evacuation was pursued because of persistent neurological deficits despite correction of alternative metabolic abnormalities. Intraoperatively, purulent material was encountered in both epidural and subdural spaces bilaterally, with cultures growing Klebsiella pneumoniae. Following bilateral evacuation and 6 weeks of intravenous antibiotics, the patient achieved complete neurological recovery. LESSONS: Subdural empyema should be considered in patients with neurological deterioration following MMA embolization, even in the setting of stable interval imaging and the absence of classic laboratory markers of infection. Although the temporal association with embolization raises the possibility of a procedure-associated mechanism, the route of infection may not always be apparent, and clinicians should maintain a broad differential diagnosis. https://thejns.org/doi/10.3171/CASE26631.