Abstract
Hirayama disease (HD) is a rare cause of cervical myelopathy often misdiagnosed as
motor neuron disease and easily missed on routine magnetic resonance imaging (MRI),
at time where detection is crucial to prevent irreversible cord injury. Believed to
be a cervical flexion myelopathy, HD differs from motor neuron diseases because of
its nonprogressive course and pathologic findings of chronic microcirculatory changes
in the lower cervical cord. Dynamic forward displacement of dura in flexion causes
asymmetric flattening of lower cervical cord. While dynamic contrast MRI is diagnostic,
routine study has high predictive value. A case of HD, etiopathogenesis, imaging and
treatment is summarized.
Key words
Cervical myelopathy - hand wasting - Hirayama disease - magnetic resonance imaging
