COVID-19 罹患後，遅発性に運動・感覚異常を呈し，電気生理学的にF 波異常を認めた小児の 2 例

Although various neurological complications have been reported to occur with coronavirus 2019 disease （COVID-19）, the details of the symptoms and foci of these complications remain unclear. We report two cases of children with delayed central and peripheral neurological symptoms and F-wave abnormalities after COVID-19. Case 1 was a 13-year-old boy who developed fever, abdominal pain, and diarrhea 1 month after COVID-19. He was admitted to our department with a diagnosis of pediatric COVID-19-related multisystem inflammatory syndrome. After treatment with high-dose immunoglobulin and intravenous steroids, he became unable to walk due to limb pain, muscle weakness, and abnormal sensations. Cerebrospinal fluid（CSF）analysis exposed elevated cell counts, and a peripheral nerve conduction study revealed prolonged latency, decreased conduction velocity, and decreased frequency of F waves. Head and spinal cord MRI showed multiple scattered signal abnormalities. These neurological symptoms improved without treatment. Case 2 was a 14-year-old boy who developed low back pain 1 month after COVID-19. He was admitted to our hospital due to persistent muscle weakness and a decreased sensation of warmth, pain, and touch in the right side of his body. Imaging studies, blood and spinal fluid tests showed no abnormalities. A peripheral nerve conduction study showed a decreased frequency of upper limb F waves and prolonged latency. The above symptoms improved without treatment. In the two patients, muscle weakness and sensory abnormalities were observed more than 1 month after COVID-19. F wave abnormalities were observed on electrophysiological examination, and the neurological prognosis was good, suggesting nerve root damage near the anterior horn of the spinal cord as one of the foci of the disease.