title: Corticosteroid-induced myopathy involving respiratory muscles in patients with chronic obstructive pulmonary disease or asthma.
abstract: We made observations on two patients with asthma and one with COPD who developed steroid-induced myopathy during prolonged treatment with high doses of corticosteroids. On admission, quadriceps force was on the average reduced to 31% of predicted (range 16 to 46% of predicted, nondominant leg), and urinary excretion of creatine in 24 h averaged 687 mg (range 275 to 1,045 mg/24 hr). Respiratory muscle involvement was evidenced by reductions in PImax and PEmax, being 38% (range 36 to 39) and 48% of predicted (range 36 to 68), respectively. Tapering of treatment with corticosteroids resulted in important recovery of quadriceps force and respiratory muscle force. In all three patients, a correlation between muscle forces and steroid dose was present during reduction of the dose. After 6 months quadriceps force averaged 62% of predicted (range 31 to 85), and PImax and PEmax reached 74% (range 52 to 92) and 92% of predicted (range 80 to 106), respectively, after 3 months. Consequently, respiratory muscle force appeared to recover faster than quadriceps force. The implications of these observations for patients treated with the usual doses of corticosteroids for shorter periods require further investigation.
authors.affiliation: Department of Medicine, Katholieke Universiteit Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Decramer
authors.forename: K J
authors.initials: KJ
authors.lastname: Stas
mesh_terms: D001249:Asthma / Q000150:complications* / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000150:complications* / Q000188:drug therapy; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D009135:Muscular Diseases / Q000139:chemically induced* / Q000175:diagnosis; D011241:Prednisone / Q000008:administration & dosage / Q000009:adverse effects*; D012132:Respiratory Muscles / Q000187:drug effects*; D013997:Time Factors
chemical_list: D011241:Prednisone; D008775:Methylprednisolone