EC Paediatrics

A 14-year-old boy with a history of fronto-ethmoidal sinusitis treated with antibiotics was admitted due to clinical deterioration. His symptoms began one week prior with frontal headache and meal-independent vomiting. Progression was marked by localized swelling in the right frontal region and fever. On admission, the patient had a temperature of 39.2°C and neck stiffness, indicating febrile meningeal syndrome. The remainder of the physical examination was unremarkable. Laboratory tests revealed leukocytosis and elevated C-reactive protein. A brain CT scan, performed one week after symptom onset, confirmed the diagnosis.

The final diagnosis was subdural empyema, a rare but serious complication of sinusitis. This condition accounts for 15 - 22% of focal intracranial infections. Historically almost always fatal before the advent of antibiotics, its prognosis has significantly improved with modern therapies. Clinically, it typically presents with fever, vomiting, and altered mental status. Rapid neurological decline usually reflects extensive hemispheric involvement.

Frontal sinusitis is the most common cause, sometimes in combination with ethmoidal or maxillary sinusitis. The infection spreads either retrogradely through septic thrombophlebitis or directly from osteomyelitis. Less frequently, it follows neurosurgical procedures. Subdural empyema is often associated with epidural empyema, cortical thrombophlebitis, brain abscess, or cortical venous infarction.

Neuroimaging is essential for diagnosis. On CT scans, the empyema appears as a hypodense collection over one cerebral hemisphere or along the falx cerebri, with sharper margins after intravenous contrast injection. CT also helps assess mass effect and midline shift. MRI with contrast, particularly diffusion-weighted imaging, provides superior sensitivity for detecting small collections, especially within the interhemispheric fissure. On T1-weighted sequences, the empyema typically appears as a crescentic or elliptical hypointense lesion adjacent to the skull or falx.

 Keywords: Subdural Empyema; CT; Brain Infection

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