Abstract
Objectives: Symptomatic myopathy in sarcoidosis patients is not always due to sarcoid myopathy (ScM). We investigated the clinical and pathological spectrum including myxovirus resistance protein A (MxA) expression among sarcoidosis patients. Methods: We reviewed the Mayo Clinic database (May 1980-December 2020) to identify sarcoidosis patients with myopathic symptoms and pathological evidence of myopathy. Results: Among 5885 sarcoidosis patients, 21 had symptomatic myopathy. Eight carried a diagnosis of sarcoidosis 5.5 years (median) prior to myopathy onset. Eleven patients had ScM. The remaining had non-sarcoid myopathies (five IBM, one immune-mediated necrotizing myopathy, one non-specific myositis, two non-specific myopathy and one steroid myopathy). Estimated frequency of IBM is 85 per 100 000 sarcoidosis patients. The following features were associated with non-sarcoid myopathies (P < 0.05): (i) predominant finger flexor and quadriceps weakness, (ii) modified Rankin scale (mRS) >2 at time of diagnosis, (iii) creatine kinase >500 U/l, and (iv) absence of intramuscular granulomas. Sarcoplasmic MxA expression was observed in scattered myofibres in three patients, two of whom were tested for DM-specific autoantibodies and were negative. Immunosuppressive therapy led to improvement in mRS ≥1 in 5/10 ScM, none of the five IBM, and 3/3 remaining patients with non-sarcoid myopathies. Discussion: Symptomatic myopathy occurred in 0.36% of sarcoidosis. IBM was the second most common cause of myopathies after ScM. Frequency of IBM in sarcoidosis is higher than in the general population. Recognition of features suggestive of alternative aetiologies can guide proper treatment. Our findings of abnormal MxA expression warrant a larger study.
Original language | English (US) |
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Pages (from-to) | 2556-2562 |
Number of pages | 7 |
Journal | Rheumatology (United Kingdom) |
Volume | 62 |
Issue number | 7 |
DOIs | |
State | Published - Jul 1 2023 |
Externally published | Yes |
Bibliographical note
Funding Information:This study was supported by the Department of Neurology, Mayo Clinic discretionary fund.
Funding Information:
Disclosure statement: P.C., M.P.S., F.C.E. and T.L. report no disclosure. M.M. has received research support from the Neurology Department and Center for Clinical and Translational Science, care centre grant award from the Muscular Dystrophy Association (MDA 497263), and an honorarium to serve as associate editor of Neurology Genetics.
Publisher Copyright:
© 2022 The Author(s). Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.
Keywords
- MxA
- granulomatous myopathy
- inclusion body myositis
- sarcoid myopathy
- sarcoidosis
PubMed: MeSH publication types
- Review
- Journal Article
- Research Support, Non-U.S. Gov't