A case of spinocerebellar ataxia accompanied by severe involvement of the motor neuron system

We report a sporadic case of spinocerebellar ataxia accompanied by later but severe involvement of the motor neuron system. A 72-year-old man began to show ataxia and dysarthria at age 66 years. Neurological examinations revealed saccadic eye movement, slurred speech, truncal ataxia, pyramidal sign, and urinary disturbance. Neither history of alcoholism nor heriditary factors were found. He developed muscular atrophy of the lower and upper extremities and limb ataxia within three years. Superficial and deep sensations were diminished in both feet four years after onset. Thus, he presented with cerebellar ataxia, bulbar sign, upper and lower motor neuron symptoms, sensory disturbance, and autonomic sign after six years at age 72. The level of serum, creatine phosphokinase (CPK) was increased, and muscle biopsy showed marked neurogenic change. Magnetic resonance imaging (MRI) revealed mild cerebellar and pontine atrophy. Although the combination of spinocerebellar ataxia and motor neuron disease is very rare, the present case suggests the inter-relation of the spinocerebellar and motor neuron systems, and presents peripheral neuropathy as a subtype of multisystem atrophy.