Muscle pathology precedes EMG change in motor neuron disease

Abstract

: Early diagnosis of amyotrophic lateral sclerosis (ALS) can be difficult to diagnosis in patients with atypical features such as unilateral focal amyotrophy or showing motor symptoms and signs of overlapping conditions like cervical spondylosis. And, brachial amyotrophic diplegia (BAD) has been recognized as a limited form of anterior horn cell disease with a benign prognosis. Case : We described a 49 year-old woman with a bilateral upper limb palsy, initially presented with paralysis of left shoulder girdle muscles, followed by paralysis of right upper limb. The initial upper limb involvements reminded of the cervical radiculopathy. After checking cervical spine images, cervical discectomy (with anterior inter-body fusion) was done. But, progression of the neurologic deficit in the affected limb was seen up to 2 years by stationary phase with no evidence of newly-developed neurologic deficits during the follow-up period. On neurologic examination, abnormal findings were limited to her arms, and revealed neither Babinski signs nor hyperreflexia. The weakness distribution (bilateral upper limb paralysis without lower limb involvement) reminded of BAD. Muscle biopsy at vastus lateralis revealed small grouped atrophy. Diagnosis was changed from BAD to ALS after muscle biopsy in lower limb.