Hirayama Disease and Other Focal Amyotrophies

Hirayama disease results in focal amyotrophy of the upper limbs. It is seen in young Asian males. Distal upper limbs are usually asymmetric, and patients can have cold paresis. Neck MRI in flexion shows dural changes and spinal cord signals in a proportion of patients. Cervical segments can be relatively long in such patients. The disease burns itself out after an initial progression of months and patients stabilize. Cervical collar therapy and in some selected patients, surgical interventions have been known to reduce the impact of the disease.