RESUMO
To analyze clinical, neuro-electrophysiologocal, imaging and pathological characteristics of Hirayama disease (HD) and review its relevant literatures to improve its diagnosis. Clinical data of two HD cases admitted to Fujian Provincial Hospital, Fuzhou during 2005 to 2008 were analyzed with literatures review. HD occurred more in males, often onset at their adolescence with muscular weakness and atrophy in one or two upper limbs, but without sensory dysfunction or pyramidal signs. Neuro-electrophysiology showed neurogenic abnormality in the body areas dominated by the 4th cervical vertebra to the 1 st thoracic vertebral (C4-T1) spinal nerves in all the patients. Magnetic resonance imaging (MRI) showed slight atrophy of the lower cervical spinal cord at routine position and its compression and forward displacement to varied extent at flexion position, with posterior epidural capsular space widening, crescent or striped high signal, and voids of vessels in some patients. Enhancement magnetic resonance scanning showed crescent sign enhanced in some patients. Biopsies of the inflicted muscles appeared slight neurogenic abnormality in some cases, and normal in other cases. HD is rarely seen clinically, but it can usually be diagnosed according to its symptoms, neuro-electrophysiology and MRI.