A case report of cyclosporine-induced myopathy with subacute muscular atrophy as initial presentation

Abstract

Rationale: Cyclosporine A (CsA) is a potent immunosuppressive agent originally used to prevent rejection after organ transplantation but now more frequently used for treatment of refractory autoimmune diseases. It can induce adverse effects, such as nephrotoxicity, gastrointestinal reactions, and gingival hyperplasia whist myopathy with subacute muscular atrophy are rare. Patientconcerns:A 55-year-old male patient with idiopathic membranous nephropathy treated with cyclosporine A at 3mg/kg/d and prednisone at 0.5 mg/kg.d for more than 20 days, gradually developed lower limb weakness, which were progressively aggravated until he was unable to stand or walk. A physical examination show muscle atrophy of both lower extremities, which was more severe in the right thigh muscle than the left, decreased muscular tension of the limbs was also observed. Diagnoses: Light microscopy and Transmission electron microscopy of muscle (quadriceps femoris) biopsy revealed druginduced myopathy rather than neurogenic damage. Interventions: Cyclosporine was withdrawn and replaced with cyclophosphamide tablets, prednisone remain unchanged and other symptomatic therapies were also administered. Outcomes: His bilateral thigh muscle atrophy showed improvement and lower limb weakness was obviously alleviated and he could stand and walk with the help of others 4 weeks later. Gradually, his thigh muscle atrophy was alleviated so that he was able to walk independently. After follow-up, no similar symptoms were found in the patients. Lessons: CsA-induced myopathy with muscular atrophy is rare and serious, which can be identified according to pathological characteristics. Abbreviations: ATPase = adenosine triphosphatase, CaN = Calcineurin, COX = Cytochrome oxidase, CsA = cyclosporine A, FOXO = forehead transcription factor O, HE = hematoxylin-eosin, IGF-1 = Insulin-like growth factor 1, MCK = muscle creatine kinase, MGT = modified gomori trichrome, MRI = magnetic resonance imaging, NADH = reduced form of nicotinamide adenine dinucleotide, NFAT = nuclear factor of activated T cells, PGC-1a = Peroxisome proliferator-activated receptor gamma coactivator 1-alpha, SHD = Succinate dehydrogenase, TEM = Transmission electron microscopy.