Myopathic changes in amyotrophic lateral sclerosis

Muscle biopsies from 111 patients 29 to 73 years of age with motor neurone disease were examined histologically. Group or individual fiber atrophy, or both, in combination with myopathic changss were noted in 75 cases (67 percent). Eight cases (7 percent) showed no detectable morphologic changes. Twenty-eight (25 percent) showed evidence of denervation atrophy alone. The age of onset and the duration of the disease did not show a definite relationship to the histologic changes; however, the majority of patients with disease for more than two years showed myopathic changes. Patients with biopsies that showed denervation and myopathic changes had a statistically significant higher serum CPK value. Possibly such changes are related to degeneration of the anterior horn cells.