Myopathy corticosteroids

Corticosteroids a chronic painless myopathy associated with the long-term use of corticosteroids is a particularly common example of drug-induced muscle disorder. It is almost certain that mild cases are overlooked because steroids are so frequently used to treat inflammatory myopathies such as polymyositis. Fluorinated steroids are particularly frequently implicated, and the incidence of drug-induced muscle disease is dose and time-related. The presence of muscle weakness can even complicate topical steroid therapy. Corticosteroid-induced myopathy is mediated via intramuscular cytosolic steroid receptors. The steroid-receptor complexes inhibit protein synthesis and interfere with oxidative phosphorylation. The myopathy is associated with vacuolar changes in muscle, and the accumulation of cytoplasmic glycogen and mitochondrial aggregations. 

Long-term use of oral corticosteroids should be avoided due to an unfavorable risk/benefit ratio. The steroid myopathy that can result from long-term use of oral corticosteroids weakens muscles, further decreasing the respiratory drive in patients with advanced disease. 

Janssens S, Decramer M. Corticosteroid-induced myopathy and the respiratory muscles. Report of two cases. Chest 1989 95(5) 1160-2. 

Similar serum enzyme elevations are found in polymyositis (A3, B4a, B20, D2, D17, E5, H7, KIO, M15, M18, Pl, P4, P5, P7, R15, S15, S26, T8, W12, W19), a nonspecific inflammatory myopathy sometimes associated with neoplastic disease but in general related to the collagen diseases and likewise responsive to corticosteroid therapy. The condition occurs at all ages in both sexes, may be acute or insidious with perhaps a normal erythrocyte sedimentation rate, may or may not be painful, or may be accompanied by an erythematous rash (dermatomyositis). Characteristically the earliest appearance of weakness is in the muscles of the pelvic... 

Local adverse effects from ICSs include oropharyngeal candidiasis and dysphonia that are dose-dependent. The dysphonia appears to be due to a local corticosteroid-induced myopathy of the vocal cords. The use of a spacer device can decrease oropharyngeal deposition and thus decrease the incidence and severity of local side effects. In infants who require delivery through a facemask, the parent should clean the nasal-perioral area with a damp cloth following each treatment to prevent topical candidal infections. 

One complication from corticosteroid use is the development of a myopathy. Based on symptoms, it is difficult to know if increased muscle weakness is due to the corticosteroid or to worsening disease... 

The increased myopathy may be due to an additive effect as both neuromuscular blockers and corticosteroids can cause myopathy. Results of an in vitro study suggested that the combination of vecuronium and meth-ylprednisolone might augment pharmacologic denervation, which may lead to myopathy and contribute to the prolonged weakness observed in some critically ill patients. ... 

Fischer JR, Baer RK. Acute myopathy associated with combined use of corticosteroids and neuromuscular blocking agents. Ann Pharmacother 996) 30,1437-45. 

Optimal treatment is not established. Corticosteroids are usually instituted initially, but a subset of patients is steroid-refractory, and myopathy may complicate long-term high-dose treatment. Second-line strategies have included pulse steroids, oral or intravenous cyclophosphamide, azathioprine, methotrexate, cyclosporin A, hydroxychloroquine, tacrolimus, MMF, y-globulins, and plasma exchange (1,2,223,225), but aU data are uncontrolled and... 

Patients receiving corticosteroid therapy show electromyographic depression of mean potential duration, correlated to the severity of hypercorticism (2 ). The mechanisms of development of myopathy during steroid therapy have been discussed (127 ). 

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