Muscle disease in progressive systemic sclerosis. diagnostic and therapeutic considerations

Upon careful examination, 23 of 24 patients with progressive systemic sclerosis (PSS) were found to have abnormalities of muscle. Nineteen patients presented a homogenous pattern of muscle abnormalities, which untreated was associated with a stable course ("simple myopathy"). Three patients demonstrated inflammatory muscle disease indistinguishable from polymyositis while a fourth patient developed marked weakness associated with a generalized neuropathic process. Muscle enzymes, electromyogram, and muscle biopsy permitted distinction among the different muscle disorders, a distinction that could have prognostic and therapeutic importance.