Corticosteroid excess in 9 patients with Cushing's syndrome or steroid myopathy was consistently associated with proximal muscle weakness, Type II muscle fiber atrophy, and mitochondrial abnormalities.
Observational (n=9)
What are the clinical, functional, biochemical, and structural characteristics of myopathy in patients with Cushing's syndrome or steroid myopathy?
Corticosteroid myopathy is characterized by proximal muscle weakness, Type II muscle fiber atrophy, and specific biochemical and electromyographic abnormalities.
In six patients with Cushing's syndrome and three with steroid myopathy, the clinical, functional, biochemical and structural characteristics of myopathy are described. Proximal muscle weakness occurred in all the patients, preferentially affected the lower limbs and was accompanied by muscle wasting in all but one patient. Force measurements confirmed quadriceps weakness in every patient. Vastus lateralis muscle biopsies showed light microscopic abnormalities in two of three patients with steroid myopathy and one of five patients with Cushing's syndrome. Type II fibre atrophy was the commonest abnormality. Reduced type II mean fibre areas occurred in all the patients with steroid myopathy and were common in Cushing's syndrome patients. Type I mean fibre areas were also reduced in two of the former group and one of the latter group and two further patients in this group had areas at the lower end of the normal range. Abnormalities in electron microscopy, mitochondrial function tests and chemical content of skeletal muscle were frequent and are described and discussed. A plasma creatine kinase activity (CK) at the lower end of the normal range, a myopathic electromyogram (EMG) and a raised 24-h urinary 3-methylhistidine/creatinine ratio on a creatine free diet were other characteristic findings in both groups of patients.
Khaleeli et al. (Tue,) conducted a observational in Cushing's syndrome and steroid myopathy (n=9). Corticosteroid excess (Cushing's syndrome or steroid therapy) was evaluated on Clinical, functional, biochemical and structural characteristics of myopathy. Corticosteroid excess in 9 patients with Cushing's syndrome or steroid myopathy was consistently associated with proximal muscle weakness, Type II muscle fiber atrophy, and mitochondrial abnormalities.