潜在性キアリ１型奇形に合併した小脳扁桃挫傷の１例

抄録

The typical clinical manifestation of Type I Chiari malformation is slowly progressive mainly in the adults. Therefore, it is rare to see the patient in acute progression of the disease, especially in the childhood. We had a 7-year-old boy with mild head trauma associated with formerly unknown Type I Chiari malformation. He had no neurological deficit other than nystagmus and headache right after the blow in the left retroauricular area. Computed tomography revealed hemorrhagic contusion in the left cerebellar tonsil. Magnetic resonan­ce (MR) image revealed tonsillar herniation to the foramen magnum and a hypoplasia of the corpus callosum, which were the strong evidence of the Type I Chiari malformation. The headache gradually improved without any invasive treatment. In the literature, some authors pointed out that the cerebellar contusion occasionally results in acute neurological deterioration. When it happens to the Chiari Type I malformation patient whose cerebellar tonsils are already herniated, the symptom could be worse. We have to be aware of such traumatic pediatric patients harboring Chiari Type I malformation.