Therapeutics and Clinical Risk Management (May 2018)
Myopathy due to HMGCR antibodies in adult mimicking muscular dystrophy associated with cancer and statin exposure – narrative review of the literature – case report
Abstract
Alzira Alves de Siqueira Carvalho,1 Vinicius Gomes da Silva,1 Edmar Zanoteli,2 David Feder3 1Laboratory of Neuromuscular Disease, Department of Neurosciences, School of Medicine of ABC, Santo André, São Paulo, Brazil; 2Department of Neurology, School of Medicine of University of São Paulo, São Paulo, Brazil; 3Department of Pharmacology, School of Medicine of ABC, Santo André, São Paulo, Brazil Abstract: Necrotizing autoimmune myopathy is characterized by predominant muscle fiber necrosis and regeneration with little or no inflammation. We describe a 58-year-old woman with previous breast cancer and statin use who complained of rapidly progressive weakness of lower limbs without pain, making walking, running and climbing stairs difficult. The creatine kinase level was 2,843 U/L, and muscle biopsy showed a dystrophic pattern. The genetic test for muscular dystrophies was negative and for anti-3-hydroxy-3-methylglutaryl coenzyme A reductase was positive. Intravenous immunoglobulin was administered, which showed mild improvement. Unfortunately, she took a step and collapsed to the floor, which led to the fracture of right femur delaying her improvement. The diagnosis of necrotizing autoimmune myopathy is sometimes delayed due to the atypical pathologic findings on muscle biopsy. As the disease is a severe condition, prompt recognition can lead to a successful outcome. We advise to consider this entity as a differential diagnosis among muscular dystrophies. Keywords: necrotizing autoimmune myopathy, HMGCR antibody, muscular dystrophy, cancer, statin
