immune-mediated necrotizing myopathy (IMNM)
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Etiology
- autoantibody directed against HMG-CoA reductase, the pharmacologic target of statins[1][2]
- occurs in a minority of patients with statin myopathy
- continues to progress even after discontinuing statin[2]
- may occur in the absence of statin prescription in patients consuming large quantities of plant sterols
Clinical manifestations
- severe, rapidly progressive proximal muscle weakness
- few extramuscular manifestations []
Laboratory
- high serum creatine kinase
- HMG CoA reductase Ab in serum
- signal recognition particle Ab in serum/plasma
Management
- immunosuppression
- glucocorticoid administration
- prednisone[1]
- most cases refractory glucocorticoids alone[7]
- recommended induction regimens
- glucocorticoids + methotrexate, intravenous immune globulin (IVIG), rituximab, azathioprine, or mycophenolate
- IVIG + rituximab in refractory cases[7]
- glucocorticoids + methotrexate, intravenous immune globulin (IVIG), rituximab, azathioprine, or mycophenolate
- glucocorticoid administration
- PCSK9 inhibitors may be alternative for lowering LDL cholesterol[6]
More general terms
References
- ↑ 1.0 1.1 1.2 Mohassel P and Mammen AL The Spectrum of Statin Myopathy. Curr Opin Rheumatol. 2013;25(6):747-752. <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/24061077 <Internet> http://www.medscape.com/viewarticle/814502
- ↑ 2.0 2.1 2.2 Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18, 19. American College of Physicians, Philadelphia 2012, 2015, 2018, 2022
- ↑ Mohassel P, Mammen AL. Statin-associated autoimmune myopathy and anti-HMGCR autoantibodies. Muscle Nerve. 2013 Oct;48(4):477-83 PMID: https://www.ncbi.nlm.nih.gov/pubmed/23519993
- ↑ 4.0 4.1 Brooks M Diet May Be a Source of 'Statin' Exposure. Medscape - Mar 21, 2018. https://www.medscape.com/viewarticle/894299
Barbacki A, Fallavollita SA, Karamchandani J, Hudson M. Immune-Mediated Necrotizing Myopathy and Dietary Sources of Statins. Ann Intern Med. 2018. Feb 20 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/29459987 <Internet> http://annals.org/aim/article-abstract/2673071/immune-mediated-necrotizing-myopathy-dietary-sources-statins - ↑ Musset L, Allenbach Y, Benveniste O et al Anti-HMGCR antibodies as a biomarker for immune-mediated necrotizing myopathies: A history of statins and experience from a large international multi-center study. Autoimmun Rev. 2016 Oct;15(10):983-93. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/27491568
- ↑ 6.0 6.1 Garcia-Diaz JD, Corral-Bueno TM, Mesa-Latorre JM et al Proprotein Convertase Subtilisin/Kexin Type 9 Antibody and Statin- Associated Autoimmune Myopathy. Ann Intern Med. 2019. Feb 19 https://annals.org/aim/article-abstract/2725149/proprotein-convertase-subtilisin-kexin-type-9-antibody-statin-associated-autoimmune
- ↑ 7.0 7.1 7.2 Rothaus C. A Woman with Weakness, Dark Urine, and Dysphagia. NEJM Resident 360. July 17, 2019 https://resident360.nejm.org/clinical-pearls/a-woman-with-weakness-dark-urine-and-dysphagia