Dados do Trabalho

Título

Unilateral corticospinal tract injury secondary to seizure or just a continuum of displasic driving pathology?

Apresentação do caso

A 7-year-old boy started to have daily seizures since 6 years old. Developmental history was normal. Seizures are described as right leg clonic jerks. He is currently on Levetiracetam, Carbamazepine and Clobazam. On the neurological exam was noticed mild left lower limb paresis with hyperreflexia. This patient underwent a pre-surgical workup with VEEG monitoring. Background was normal but frequent epileptiform discharges were seen at the vertex and the left fronto-central region. During VEEG monitoring he exhibited right leg clonic seizures with vertex origin. Brain MRI showed subtle blurring over the left paracentral lobule and increased T2 signal throughout the entire length of the left corticospinal tract (CT). Tractography of the CT revealed incipient axonal injury. [18F]FDG PET showed focal glucose hypometabolism over the left mesial fronto-parietal region (supplementary motor area and paracentral lobule). The hypothesis was focal cortical dysplasia.

Discussão

Some abnormalities on MRI are well described after cluster of seizures and status epilepticus. These signal alterations are most seen in cortical or subcortical areas, splenium of the corpus callosum, basal ganglia, hippocampus and leptomeninges. We described a unilateral abnormal CT signal that was confirmed by tractography in a patient with daily focal motor seizures. The white matter tract abnormalities have been reported in the displasic tissue adjacent areas, represented by reduced tract fibers connectivity, as part of the displasic pathology driving mechanisms. These abnormalities can also be a result of metabolic abnormalities that lead to a combination of vasogenic and cytotoxic edema induced by seizure activity. The CT abnormal sign in our case may be due to seizure spread pathway, just enhanced by recent intense seizure activity, but also an evidence of disturbed neuronal connectivity secondary to dysplasia.

Comentários finais

This case highlights the importance of this MRI white matter findings being part of the epilepsy pathophysiology like a result of displasic pathology driving mechanisms or transitory damage secondary to seizure activity, therefore reducing the risk of misdiagnosis and unnecessary intervention.