Diffusion MRI abnormalities after prolonged febrile seizures with encephalopathy

Area of Science:

• Pediatric Neurology
• Neuroradiology
• Neuroscience

Background:

• Encephalopathy following prolonged seizures can present with abnormal subcortical white matter on diffusion-weighted MRI (DWI).
• Identifying common features in these patients is crucial for diagnosis and understanding the condition.

Purpose of the Study:

• To determine if patients with encephalopathy after prolonged seizures share common clinical, laboratory, and radiologic features.
• To characterize the MRI findings, particularly diffusion-weighted imaging (DWI) abnormalities, in this patient group.

Main Methods:

• Retrospective review of clinical, laboratory, and radiologic data from 17 patients with encephalopathy after prolonged seizures and abnormal subcortical white matter on MRI.
• Analysis of seizure characteristics, MRI findings (DWI and T2-weighted), and clinical outcomes.

Main Results:

• All 17 patients (ages 10 months to 4 years) experienced prolonged febrile seizures (>1 hour in 12).
• Subcortical white matter lesions on DWI appeared 3-9 days post-seizure, with T2-weighted images showing U-fiber hyperintensity in 13 patients.
• Lesions were predominantly frontal/frontoparietal, sparing the perirolandic region; diffusion abnormalities resolved between 9-25 days.

Conclusions:

• These patients exhibit a distinctive encephalopathy syndrome with characteristic MRI findings.
• Diffusion-weighted MRI is instrumental in diagnosing this specific encephalopathy.
• The underlying pathophysiologic mechanism requires further investigation.