Inclusion body myositis — SCE Neurology MCQ

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HardNeuropathologyInclusion body myositisSCE Neurology

A 66-year-old develops rapidly progressive proximal weakness and dysphagia three months after atorvastatin was stopped. CK is 9,800 IU/L and biopsy shows myofibre necrosis with little lymphocytic inflammation. Which antibody is most informative?

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Correct answer: C — Anti-HMGCR antibody

The best answer is “Anti-HMGCR antibody”. Persistent severe necrotising myopathy after statin withdrawal is characteristic of anti-HMGCR immune-mediated necrotising myopathy, which usually requires immunotherapy rather than simple drug cessation. “Acetylcholine-receptor antibody” is less appropriate because AChR antibodies identify myasthenia with normal CK and no necrotising biopsy “Aquaporin-4 antibody” is less appropriate because AQP4 antibodies define NMOSD “LGI1 antibody” is less appropriate because LGI1 antibodies cause limbic encephalitis and faciobrachial seizures “Voltage-gated calcium-channel antibody” is less appropriate because presynaptic calcium-channel antibodies support Lambert–Eaton syndrome

Reference: Immune-mediated necrotising myopathy: a critical review. https://pmc.ncbi.nlm.nih.gov/articles/PMC11843977/