Immune-Mediated Necrotizing Myopathy: An Often Misdiagnosed Entity

Abstract

Immune-mediated necrotizing myopathies (IMNM) are recognized as a subgroup of idiopathic inflammatory myopathies (IIM). IMNM are defined based on a combination of clinical presentation and laboratory studies, requiring a specific myopathological pattern on muscle biopsy for diagnosis. The authors describe a case of a patient with necrotizing myopathy, thought to be immune mediated, highlighting the challenge of its differential diagnosis. As clinical assessment and diagnostic tools sometimes fail to determine whether a necrotizing myopathy is immune mediated, leading to misdiagnosis and a compromise of the optimal therapeutic approach, distinguishing between IMNM and other myopathies is crucial.

A rare cause of proximal muscle weakness: immune necrotising myopathy

“…Immune-mediated necrotising myopathies are recognised as a subgroup of idiopathic inflammatory myopathies. 1 They are characterised clinically by the subacute onset of proximal limb weakness, elevated creatinine kinase (CK) levels and myopathic findings on electromyography. They are distinguished from other inflammatory myopathies by the presence of necrosis and the absence of prominent infiltration in muscle biopsy.…”