Restricted Diffusion in the Bilateral Subcortical Motor Areas Associated with Status Epilepticus in an Infant with Kawasaki Disease.

Status epilepticus (SE) often causes neuronal death in the cerebrum and consequent long-term sequelae. Acute encephalopathy with biphasic seizures and late reduced diffusion is clinically characterized by SE associated with fever and seizure clusters that occur 3-9 days after symptom onset. MRI reveals reduced diffusion in the frontal or frontoparietal subcortical white matter, with sparing of the perirolandic region following seizure clusters. Kawasaki disease (KD) is an acute self-limited vasculitis secondary to activation of the immune system; KD is rarely complicated by acute encephalopathy. We report the case of a male infant who developed SE associated with KD and showed late reduced diffusion in the subcortical white matter beneath the bilateral motor cortices (primary motor, premotor and supplementary motor areas) and the right frontal cortex. The patient had characteristic neurological sequelae in the chronic phase, including clumsiness of fingers and forearms, impaired discrimination of tactile sensation and position sense on digits in his hands and feet, corresponding to the lesions with reduced diffusion at the acute phase.