Focal Status Epilepticus-Related Unilateral Brain Edema: Magnetic Resonance Imaging Study of Children in Southwest China

Unilateral brain edema is a rare peri-ictal imaging abnormality related to focal status epilepticus. We present the largest series of these patients, describe their clinical features and magnetic resonance imaging (MRI) findings, and analyze the possible underlying pathophysiology. We reviewed the medical records in Southwest China’s largest tertiary’s children’s medical center from 2011 to 2017. Patients with focal status epilepticus were included if acute-phase cerebral MRI showed unilateral edematous swelling of the epileptic hemisphere. Eleven children were included. The age at which the patients presented with status epilepticus ranged from seven months to 10.8 years. All patients showed prolonged clonic seizures with marked unilateral predominance followed by hemiplegia of the ipsilateral limbs. The seizure duration ranged from one to 72 hours. All patients showed hyperintensities on T2-weighted images and diffusion-weighted images involving the whole pathologic hemisphere. Three patients showed involvement of the contralateral cerebellar hemisphere and one showed hippocampal herniation. Magnetic resonance angiography of the brain was performed in seven patients, among which three showed dilation of the affected hemispheric arteries. Three patients underwent follow-up MRI, and all the examinations revealed ipsilateral cerebral hemisphere atrophy. Focal status epilepticus may cause unilateral brain edema, and cytotoxic edema probably plays an important role in the pathophysiology of brain injury.