Hirayama flexion myelopathy

Excerpt

A 16-year-old white male, with a history of cerebral palsy with both features of diplegia and right hemiplegia, as well as mild intellectual disability, presented with an over one-year history of progressive right hand weakness. He denied sensory symptoms, pain or any trauma. Neurological examination revealed strength impairment and mild atrophy in right C7–T1 myotomes without sensory disturbances. Nerve conduction studies of right upper limb were unremarkable. Electromyographic examination, performed in right arm muscles, confirmed a chronic neurogenic pattern with high amplitude rapidly firing motor unit potentials associated with denervation signs (fasciculations, fibrillation potentials and positive sharp waves) in C7–T1 muscles. There were no bladder or bowel complaints or changes in his mild diplegic gait. Dynamic cervical X-rays were normal, conversely dynamic cervical-MRI (Fig. 1a–c) showed myelopathic changes and hypermobility of the dura causing cord compression during flexion, suggesting Hirayama disease (HD).

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