Atypical onset of idiopathic inflammatory myopathy sensitive to steroids under the mask of amyotrophic lateral sclerosis: A case report

Idiopathic inflammatory myopathy is a heterogeneous group of autoimmune disorders, that share some common manifestations, such as muscle weakness and elevation of serum creatine kinase. However, classification of idiopathic inflammatory myopathy into an existing clinical subtype is not always possible. The case is a 25-year-old male with an unrecognized form of idiopathic inflammatory myopathy, the onset of which resembled amyotrophic lateral sclerosis. The paper includes differential diagnosis with amyotrophic lateral sclerosis and congenital myopathies, and response to corticosteroid therapy.