Quiz Form

Question Date: 20/10/2023

Question: Which of these statements is true regarding immune mediated necrotizing myopathy?

Options:

• Muscle biopsy shows necrotic fibers with marked inflammation
• Anti SRP myopathy responds to corticosteroids
• Anti HMGCR antibody is exclusively seen in statin exposed patients
• Early aggressive treatment is needed for improvement

Correct Answer: Early aggressive treatment is needed for improvement

Explaination: Immune mediated necrotizing myopathy resembles polymyositis and is associated with antibodies against signal recognition particle (SRP) or HMG CoA reductase (HMGCR). Anti HMGCR antibodies, while first described in statin myopathy, can also be seen in patients who are not exposed to statins. Muscle biopsy shows necrotic muscle fibers with minimal inflammatory cell infiltration. It is an aggressive disease causing muscle fibrosis, hence aggressive treatment is required. Anti SRP myopathy does not respond favorably to corticosteroids and rituximab may be advisable

Reference: Doughty C T, Amato A A. Disorders of Skeletal Muscle. Bradley and Daroffs Neurology in Clinical Practice. 2022. Ch 1091978