Hirayama disease in Austria.

Objectives: Hirayama disease (HD) is a segmental cervical myelopathy which affects the C7-D1 myotomes and presents with unilateral or asymmetric upper limb weakness/wasting. The study aimed at systematically collecting cases of HD in Austria and at describing and discussing their presentation on clinical and instrumental investigations and at comparing them with cases reported from other countries.

Methods: Neurological Departments of secondary and tertiary centers and colleagues in outpatient units involved in the management of neuromuscular disorders in Austria were contacted and asked to provide standardised data about their HD cases.

Results: Altogether, nine unrelated cases were included. Mean age at onset was 18.3 years (range: 12.5-27 years). The female-to-male ratio was 0.29. Mean disease duration was 18.8 years. All patients presented with weakness or wasting of the distal upper limb muscles. A single arm (right: n=2, left: n=3) was affected in five cases and both arms in four. Six patients presented with tremor, two with fasciculations. EMG showed chronic neurogenic changes in all patients. Conventional cervical MRI was normal (n=1), showed focal atrophy (n=3), an intramedullary lesion (n=3), or abnormal straightening of the cervical spine (n=1). Dynamic MRI in a single patient showed anterior displacement of the dorsal dura, prominent epidural space, compressed cord over the posterior surface of vertebra C5-6, and a prominent crescent-shaped mass. Two patients received physiotherapy with beneficial effect in one.

Conclusions: HD rarely also occurs in Austria, predominantly males are affected, and clinical presentation, course and outcome are not at variance from cases in other European or non-European countries.