Pneumocephalus Without Visible Fracture Preceding Subdural Empyema: A Delayed Emergency Department Diagnosis.

BACKGROUND: Subdural empyema is a rare, rapidly progressive intracranial infection that may follow sinusitis, craniofacial trauma, or contiguous facial infection. Early findings may be subtle, and delayed recognition in the emergency department can result in neurologic deterioration. CASE REPORT: A 16-year-old male presented approximately 2 hours after minor blunt frontal trauma after striking his forehead against a car hood. Because he vomited twice, cranial computed tomography (CT) was performed and showed no visible fracture, acute intracranial pathology, or paranasal sinus opacification. He was discharged. On Day 1, he re-presented with frontal scalp and bilateral periorbital swelling and erythema. Repeat CT demonstrated pneumocephalus without visible fracture and new mild frontal, ethmoid, and maxillary sinus opacification. On Day 2, he was admitted with preseptal cellulitis and started on intravenous antibiotics. On Day 6, he developed vomiting followed by a generalized tonic-clonic seizure; his Glasgow Coma Scale score remained 5, requiring endotracheal intubation. Magnetic resonance imaging demonstrated a right frontal extra-axial collection suspicious for empyema with dural and leptomeningeal enhancement and restricted diffusion. Burr-hole drainage on Day 8 revealed pus, confirming subdural empyema. He completed antimicrobial therapy and remained neurologically intact without seizure recurrence at 1-month follow-up. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pneumocephalus without visible fracture on return presentation should be treated as a warning sign. It should prompt skull-base and sinus imaging review, early otorhinolaryngology, infectious diseases, and neurosurgical consultation, consideration of admission, and a low threshold for repeat neuroimaging.