- Discussion:
- individual fibers are affected in random fashion throughout the muscle;
- muscle fibers become rounded, will vary in size;
- nuclei frequently migrate centrally;
- may see phagocytosis of individual cells;
- unlike neuropathic disease, in myopathy, active regeneration of fibers is seen;
- muscle disuse leads to type II fiber atrophy;
- type II fibers are more susceptible to atrophy and are more frequently involved in myopathies than are type I;
- in contrast, type I fibers display more atrophy in congenital myopathies & in myotonic dystrophy