Immune-mediated necrotizing myopathy (IMNM): A myopathological challenge

Merlonghi, Gioia; Antonini, Giovanni; Garibaldi, Matteo

doi:10.1016/j.autrev.2021.102993

Cited by 23 publications

(22 citation statements)

References 89 publications

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“…Muscle biopsy findings in IMNM show prominent necrosis and regeneration of muscle fibers, along with a key feature of mild or absent inflammatory infiltrates. Histopathological differences between anti-SRP and anti-HMGCR include more severe necrosis and regeneration in anti-SRP, sarcolemmal expression of MHC-1 in isolated fibers in anti-SRP, and in clustered fibers in anti-HMGCR, and three times greater expression of sarcolemmal C5b-9 in anti-HMGCR compared to anti-SRP [13]. The detailed pathologic features of seronegative IMNM have not yet been described in the literature [1,13].…”

Section: Discussionmentioning

confidence: 99%

Seronegative Immune-Mediated Necrotizing Myopathy: A Case Report

Patel¹,

Abu-Abaa²,

Mousavi³

2022

Cureus

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Idiopathic inflammatory myopathies (IIMs) are a group of chronic autoimmune disorders characterized by proximal skeletal muscle weakness. One subtype of the IIMs is immune-mediated necrotizing myopathy (IMNM). IMNM can be further classified according to its autoantibody presence, including anti-3-hydroxy-3methylglutaryl-coenzyme A reductase (HMGCR), anti-signal recognition particle (SRP), and seronegative.Here, we describe the case of a 61-year-old Caucasian female with a prior history of distant lung cancer and current statin use presenting with a subacute onset of bilateral proximal lower extremity muscle weakness and markedly elevated creatinine kinase (CK) and amino transaminases. In the acute inpatient setting, she underwent successful treatment with corticosteroids that were eventually discontinued and replaced with azathioprine three months after hospital admission. At that point, she had attained a 60% increase in muscle strength.

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Section: Discussionmentioning

confidence: 99%

Seronegative Immune-Mediated Necrotizing Myopathy: A Case Report

Patel¹,

Abu-Abaa²,

Mousavi³

2022

Cureus

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“…It has been postulated that as the implant elastomer ages, silicone can trigger macrophage activation, leading to further histiocytic reaction with siliconomas including at distant sites. Interestingly, our first patient presented with immune-mediated necrotizing myopathy, a disease characterized by a scant inflammatory infiltrate of a predominant monocytic lineage [ 15 ]. It is perhaps important to note the proximity of the gluteal implants to thigh muscle extensors as well as the inflammatory infiltrate that was aspirated from the periprosthetic area.…”

Section: Discussionmentioning

confidence: 99%

Two Cases of Autoimmune Syndrome Induced by Adjuvants (ASIA): A Multifaceted Condition Calling for a Multidisciplinary Approach

Loftis¹,

Nunez²,

Garza³

et al. 2022

Cureus

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Silicone implants have been used for cosmetic enhancement and reconstructive purposes for over 60 years. Despite assiduous efforts to ensure safety, there is continuous evidence that they are not as biologically inert as previously postulated. We present two cases of autoimmune syndrome induced by adjuvants (ASIA) in Hispanic women. The first patient developed biopsy-proven immune-mediated necrotizing myopathy that was successfully treated with the combination of silicone explantation along with immunosuppressive therapy. Findings after implant removal demonstrated rupture and leakage of silicone from gluteal implants. The second patient developed autoimmune hemolytic anemia in the setting of a ruptured silicone breast implant. Similarly, the patient was treated with corticosteroids followed by breast implant removal with complete resolution of symptoms. The successful treatment of these patients was achieved by collaboration between rheumatology and plastic surgery, which emphasizes the need for a multidisciplinary approach in the diagnosis and management of patients with ASIA.

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“…The diversity and lack of specificity of muscle pathology in IMNM is increasingly recognized and reported, and these cases further highlight the importance of interpreting the muscle biopsy with knowledge of the clinical context. 4 In addition, anti-HMGCR and anti-SRP antibodies have very low false positive and false negative rates, depending on the type of assay, and therefore the antibodies should also be interpreted in the appropriate clinical context. 5 In summary, we steadfastly agree with the authors on the importance of not missing the diagnosis of IMNM, due to its potential treatability.…”

Section: Atypical Presentations Of Immune-mediated Necrotizing Myopat...mentioning

confidence: 99%

“…In contrast to the nonspecific myopathological findings, hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and signal recognition particle (SRP) antibodies have shown a high specificity for the diagnosis of IMNM, and false positive results are not expected among patients with inherited myopathies. 4 These autoantibodies represent an easily accessible means of detecting previously unsuspected cases of IMNM, especially in patients with a young age of onset, chronic course of disease, positive family history without genetically identified etiology, or atypical myopathological findings. 5,6 We found that these atypical presentations represented approximately 5% of IMNM cases in our cohort.…”

Section: Reply To: Atypical Presentations Of Immune-mediated Necrotiz...mentioning

confidence: 99%