Search

We describe the varied clinical presentations, barriers in diagnosis and outcomes of anti-HMGCR myopathy in a large national cohort. Adults found positive for serum anti-HMGCR autoantibodies via line blot or enzyme-immunoassay followed by immunoprecipitation were included in the study. Of 75 patients identified, the records of 72 (96 %) described weakness as the presenting symptom. The records of 65 gave a reliable description of proximal weakness. In 22/65 (33.8 %) the weakness was described as predominantly or solely lower limb weakness. Forty-five of 75 (60 %) presented with a subacute onset (duration of symptoms >4 weeks -≤6 months), whilst 22/75 (29.3 %) presented with a more indolent chronic onset (duration of symptoms >6 months). Eighteen of 75 (24 %) suffered falls and 2/75 (2.7 %) had "general decline". In three patients no weakness was described: two presented with myalgia and one with a skin rash characterized as Jessner lymphocytic skin rash. Median creatine kinase at presentation was 7337 U/L (range 1050–25,500). Muscle biopsy was performed in 38 (50.7 %). Associated malignancy was infrequent. Four patients recovered without immunosuppression. Five-year and 10-year survival was 92.7 % (95 % CI 80.6–97.4 %), and 82.5 % (95 % CI 61.2–92.8 %) respectively. Recurrent falls, a long prodrome and dominant lower limb proximal weakness were common in this anti-HMGCR myopathy cohort. These features overlap with frailty syndrome and sporadic inclusion body myositis emphasizing the importance of considering anti-HMGCR myopathy in that clinical context. A minority of patients recover after statin withdrawal alone. [Display omitted] [ABSTRACT FROM AUTHOR]

• In northern Spain, anti-HMGCR IMNM usually affects people over 50 years with exposure to statins. • We confirm that HLA-DRB1×11 is associated with an increased risk of anti-HMGCR IMNM in Spain. • The SLCO1B1 gene does not seem to play a role in the anti-HMGCR IMNM genetic network. • Vitamin D deficiency and hypothyroidism might be predisposing factors for anti-HMGCR IMNM. To characterize the demographic, genetic, clinical, and serological features of patients with anti-3‑hydroxy-3-methylglutaryl-CoA reductase (HMGCR) immune-mediated necrotizing myopathy (IMNM) in a region of northern Spain. Study of all patients diagnosed with anti-HMGCR IMNM during a 5-year period at a reference hospital in northern Spain. Besides clinical and laboratory data, we analyzed the genetic influence of HLA genes and the rs4149056 (c.521T>C) single nucleotide polymorphism (SNP) in the SLCO1B1 gene. 8 patients (5 women, 3 men) with a mean ± SD age of 64.9 ± 7.3 years, fulfilled the criteria for anti-HMGCR IMNM. The incidence rate was 0.6 per 100.000 person-years and the prevalence 3 per 100.000 population. All patients had been exposed to statins. All of them had predominant lower limb proximal and symmetric muscle weakness that was severe in 2 and had elevated serum CK levels with a median [IQR] of 4488 [2538–9194] IU/L. Serum 25‑hydroxy vitamin D levels were decreased in all patients in whom it was determined. The 3 patients with a previous diagnosis of hypothyroidism had abnormal levels of TSH at the time of diagnosis. All patients experienced improvement with different schemes of immunosuppressive therapy. Noteworthy, 7 of 8 patients carried the HLA-DRB1*11 allele. The frequency of the rs4149056 C allele in the SLCO1B1 gene (12.5%) was similar to that of the general population. In northern Spain, anti-HMGCR IMNM preferentially affects people over 50 years of age who are carriers of the HLA-DRB1*11 allele and take statins. Both low vitamin D levels and hypothyroidism may play a potential predisposing role in the development of this disease. [ABSTRACT FROM AUTHOR]

• IVIg may be replaced by SCIg in the maintenance therapy of anti-HMGCR myopathy. • SCIg induced a sustained clinical stability in anti-HMGCR myopathy. • Anti-HMGCR antibodies are an important marker for the prognosis and response to therapy. We describe the clinical response to long-term subcutaneous immunoglobulins (SCIg) in anti-3‑hydroxy-3-methyl-glutaryl-coenzyme-A-reductase (anti-HMCGR) myopathy previously treated with intravenous immunoglobulins (IVIg). We collected data from patients affected by anti-HMGCR myopathy, switched from IVIg to SCIg therapy, after achieving clinical stabilization. The Medical Research Council sum score, creatine kinase (CK) levels, and anti-HMGCR antibodies were used to assess the response. We identified three patients with anti-HMGCR myopathy treated with SCIg with a favourable clinical course, allowing the maintenance of clinical stability, the reduction or suspension of steroids therapy and in two of them a complete CK normalization. Finally, anti-HMGCR antibodies tested in all patients after 12 months from SCIg starting, showed a global decrease. SCIg represent an useful alternative to long-term IVIg as already well known in several autoimmune neuromuscular disorders and inflammatory myopathies with advantages of lower side effects and home self-administration. [ABSTRACT FROM AUTHOR]

The major forms of autoimmune myopathies include dermatomyositis (DM), polymyositis (PM), myositis associated with antisynthetase syndrome (ASS), immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). While each of these conditions has unique clinical and histopathological features, they all share an immune-mediated component. These conditions can occur in isolation or can be associated with systemic malignancies or connective tissue disorders (overlap syndromes). As more has been learned about these conditions, it has become clear that traditional classification schemes do not adequately group patients according to shared clinical features and prognosis. Newer classifications are now utilizing myositis-specific autoantibodies which correlate with clinical and histopathological phenotypes and risk of malignancy, and help in offering prognostic information with regard to treatment response. Based on observational data and expert opinion, corticosteroids are considered first-line therapy for DM, PM, ASS, and IMNM, although intravenous immunoglobulin (IVIG) is increasingly being used as initial therapy in IMNM related to statin use. Second-line agents are often required, but further prospective investigation is required regarding the optimal choice and timing of these agents. [ABSTRACT FROM AUTHOR]

Immune-mediated necrotizing myopathy (IMNM) associated with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) autoantibodies occurs in patients both with and without history of statin-intake. The mechanisms of muscle fiber degeneration in this condition remain unknown. We studied pathological changes in muscle biopsies from three patients lacking history of statin-intake. Ultrastructural observations showed accumulation of degenerating mitochondria, glycogen granules and autophagic vacuoles, forming large composites in three cases, along with various nonspecific changes. The autophagic vacuoles often contained remnants of mitochondria, indicating mitophagy. Furthermore, upregulation of B-cell lymphoma 2/adenovirus E1B 19 kD-interacting protein 3 (BNIP3), a protein involved in mitophagy, was observed in two cases examined. In three cases of sporadic inclusion body myositis, two polymyositis, and three IMNM with anti-signal recognition particle antibody, BNIP3 was upregulated less frequently, and ultrastructural change of mitophagy was rarely seen. These findings suggested that mitophagy plays an important role in muscle fiber degeneration in IMNM with anti-HMGCR autoantibodies. [ABSTRACT FROM AUTHOR]

Necrotizing myopathies can be encountered in various conditions as acquired myopathies (toxic or autoimmune) or muscular dystrophies. We report a twenty-year-old Caucasian woman who presented with clinical findings suggestive of an inflammatory myopathy: subacute onset of lower limb muscle weakness, myalgia, weight loss and absence of family history. The serum creatine kinase level was elevated at 4738 IU/L (normal range, 25–175 IU/L). Muscle biopsy was consistent with necrotizing myopathy. The patient showed significant clinical improvement following corticosteroid, azathioprine and intravenous immunoglobulin treatments. Biological tests revealed no specific autoantibodies associated with necrotizing autoimmune myopathies. Immunohistochemical staining for sarcolemmal proteins in muscle biopsy samples finally led to a diagnosis of limb-girdle muscular dystrophy 2I (fukutin-related protein gene mutations). The response to immune therapies suggested a possible inflammatory component associated with the muscular dystrophy and highlighted the potential benefit of corticosteroid treatment in patients with LGMD2I and subacute onset. [ABSTRACT FROM AUTHOR]

Necrotizing autoimmune myopathy (NAM) is a rare variant of idiopathic inflammatory myopathies associated with various underlying conditions. We describe a 48-year-old woman with a history of breast cancer who presented with acute respiratory failure and progressive loss of strength in her limb muscles over a period of two months. Muscle biopsy was consistent with necrotizing myopathy. No signs of active tumour were found. Immunoblot was positive for anti-melanoma differentiation-associated gene 5 (MDA5) antibodies. Based on the subacute onset and muscle biopsy a diagnosis of NAM was made. Treatment with immunosuppressive and immunomodulating therapy led to almost complete recovery. Respiratory insufficiency as a presenting symptom of NAM is unusual. Recognition of this manifestation is crucial as early and aggressive treatment can lead to substantial recovery. [ABSTRACT FROM AUTHOR]

Only few reports exist regarding the coexistence of multiple sclerosis (MS) and autoimmune myopathies. We describe the case of a man with a long history of undiagnosed left lower limb motor impairment who was hospitalized for subacute onset of a myopathic syndrome. In addition, neurological examination revealed sensory impairment and pyramidal signs in the left limbs. Muscle biopsy revealed a necrotizing myopathy and serum anti-signal recognition particle (SRP) antibodies were found. Brain and spinal cord MRI displayed several non-enhancing demyelinating lesions, and CSF-restricted oligoclonal bands were detected. Multimodal evoked potentials showed increased latency of central conduction. Total body PET-CT did not reveal malignancies. A final diagnosis of anti-SRP necrotizing autoimmune myopathy (NAM) and MS was made, and subsequent therapy with azathioprine resulted in a complete stability for both diseases during the follow up. To the best of our knowledge this is the first reported case of concomitant NAM and MS. [ABSTRACT FROM AUTHOR]

Of 207 adult patients with idiopathic inflammatory myopathies, detection of autoantibodies by RNA immunoprecipitation showed that 99 patients (48%) were antibody-positive. We divided these 99 into five subgroups: anti-signal recognition particle (SRP), anti-aminoacyl transfer RNA synthetase, anti-Ku, anti-U1RNP, and anti-SSA/B. Younger age at onset, severe weakness, muscle atrophy, elevated creatine kinase, and necrosis in muscle fibers without inflammatory cell infiltration were found significantly more frequently among the patients with anti-SRP antibodies ( n = 41) compared to the antibody-negative patients ( n = 108). Autoantibody detection by RNA immunoprecipitation can provide useful information associated with clinical and histological findings. [ABSTRACT FROM AUTHOR]

Introduction: Statins or 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (HMGCR) are among the most commonly prescribed treatment in France. They may be responsible for muscular intolerance with variable severity. They have been recently involved in the occurrence of an acquired inflammatory myopathy associated with anti-HMGCR antibodies. This new type of toxic myopathy remains poorly known by clinicians. Observation: We report a 61-year-old woman treated with a statin for many years who developed a lower and upper limb disabling myopathy with a rapid unfavourable course despite treatment withdrawal. Clinical history and investigations, especially including an assay for anti-HMGCR antibodies led to the diagnosis of autoimmune necrotizing myopathy with anti-HMGCR antibodies. Subsequent initiation of an immunosuppressive treatment by corticosteroids and methotrexate was effective. Conclusion: Statins may unmask or cause an autoimmune necrotizing myopathy associated with the presence of anti-HMGCR antibodies. Their identification is now routinely available. An immunosuppressive treatment is necessary and justified by the autoimmune nature of the disease. [ABSTRACT FROM AUTHOR]

Résumé: Les patients présentant des symptômes musculaires ou une élévation des enzymes musculaires peuvent souffrir d’une myopathie. Dans ce cas, le médecin doit confirmer ce diagnostic et distinguer s’il s’agit d’une maladie acquise ou génétique. Si la maladie est acquise, après avoir écarté une cause infectieuse, toxique ou endocrinienne, il devra déterminer de quel type de myopathie acquise idiopathique il s’agit : soit d’une myosite incluant la polymyosite, la dermatomyosite ou la myosite à inclusions, soit d’une myopathie nécrosante auto-immune. L’examen histologique musculaire est déterminant mais la détection d’auto-anticorps est maintenant devenue cruciale dans cette démarche. Les anticorps spécifiques des myosites ainsi que ceux associés aux myosites permettent une approche diagnostique sérologique complémentaire de l’étude histologique. En effet, il existe une forte association entre un auto-anticorps spécifique et un phénotype de maladie musculaire et son évolution. La présence d’anticorps anti-synthétase est associée avec une présentation histologique originale entre polymyosite et dermatomyosite et définit un syndrome où l’atteinte pulmonaire interstitielle gouverne le pronostic. L’anti-MDA-5 est uniquement observé chez les patients présentant une dermatomyosite et définit un syndrome cutanéo-pulmonaire dont l’évolution est souvent sévère. L’anti-TIF1-γ est lui aussi associé à la dermatomyosite mais dans ce cas sa présence est corrélée à celle d’un cancer, alors que l’anti-MI2 est associé à une forme classique de dermatomyosite. Deux anticorps spécifiques des myopathies nécrosantes auto-immunes sont décrits à ce jour : l’anti-SRP (single recognition particle) et l’anti-HMGCR (hydroxyméthylglutaryl-coenzyme A réductase). Leur détection est peut-être déterminante en particulier dans le cas de myopathies à début lentement évolutif pouvant conduire à tort au diagnostic de dystrophie musculaire et privant ainsi le patient de traitements efficaces. [Copyright &y& Elsevier]

Immune-mediated necrotizing myopathy (IMNM) associated with statin use and anti 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibody is a new and emerging entity that supports a link between statin use and IMNM and raises the questions of distinct clinical phenotypes and treatment strategy. We describe the clinical and histopathological characteristics of a patient and discuss the spectrum of IMNM and statin-induced myopathies. A 65-year-old man was suffering from proximal muscle weakness and elevated CK levels, following exposure to statin therapy. The symptoms worsened despite discontinuation of the drug. At that point, no myositis-specific or -associated antibodies were detected. Malignancy screening did not reveal abnormalities. Muscle biopsy demonstrated a predominantly necrotizing myopathy with minimal lymphocytic infiltrates, MHC class I expression in necrotic muscle fibers, and complement deposition on scattered non-necrotic muscle fibers. Muscle protein analysis by western blot was normal. The patient did not improve with steroid and methotrexate and required monthly intravenous immunoglobulin (IVIG) therapy. Muscle strength gradually improved, CK levels normalized and IVIG were stopped 1 year later. Screening for anti-HMGCR antibodies, not available at the time of presentation, was highly positive. Identification of anti-HMGCR antibodies in statin-exposed patients with myopathy appears to be helpful both for differential diagnosis and for treatment strategy. In patients who did not improve after discontinuation of the statin treatment, a muscle biopsy should be performed as well as screening for anti-HMGCR antibodies. Patients with this disorder require aggressive immunosuppressive treatment. [ABSTRACT FROM AUTHOR]

Abstract: The mechanism of necrotizing myopathy associated with antibodies to signal recognition particle (SRP) remains unclear. We investigated the effect of anti-SRP+serum and complement on cell viability in myoblast cultures. Cell viability was only slightly reduced by incubation with anti-SRP+serum compared with control serum. However, the addition of fresh complement resulted in a marked reduction in cell survival. Surface immunostaining for SRP, C3c and C5b-9 was demonstrated in cultures pre-incubated with anti-SRP+serum and complement, and in muscle biopsies from patients with myopathy. These findings provide further support for a complement-dependent antibody-mediated mechanism in anti-SRP associated myopathy. [Copyright &y& Elsevier]

Résumé: Les myopathies nécrosantes (MN) ont une définition histologique. Elles sont caractérisées par l’importance des phénomènes nécrotiques (fibres musculaires en nécrose associées à d’autres en régénération) et l’absence d’inflammation musculaire. Elles peuvent être acquises ou être l’expression histologique d’une myopathie d’origine génétique. Lorsqu’elles sont acquises, après avoir écarté une cause toxique, il faut évoquer un mécanisme auto-immun. Les MN acquises auto-immunes (MNAI) constituent aujourd’hui un groupe distinct des myosites, en particulier des polymyosites avec lesquelles elles étaient confondues jusqu’alors. Elles ont classiquement un début aigu et sont souvent sévères avec parfois des complications cardiaques. Elles justifient donc un traitement précoce qui doit être prolongé. Parfois, elles peuvent être beaucoup plus lentement évolutives mimant ainsi une dystrophie des ceintures. Les MNAI peuvent être associées à la présence d’auto-anticorps spécifiques contre la protéine SRP, ou plus récemment mise en évidence, la protéine HMG-CoA réductase. Les MNAI peuvent aussi être associées à certaines connectivite comme le lupus ou la sclérodermie. En l’absence d’auto-anticorps spécifiques ou de connectivite associés il faut rechercher un cancer dont la présence a aussi été rapportée au cours des MNAI. Ainsi, les MNAI ont émergé dans le champ de la myologie comme une nouvelle entité. Elles ont modifié les cadres définis jusqu’alors et donc notre démarche diagnostique, y compris dans le domaine des dystrophies musculaire. [ABSTRACT FROM AUTHOR]

Abstract: Capecitabine plus oxaliplatin combination (XELOX) is the first-line treatment in metastatic colorectal cancer. Here we report a case of acute, severe but substantially reversible, neuromuscular and cardiac toxicity following XELOX chemotherapy. Muscle biopsy findings were consistent with a toxic myopathy with necrotizing features and vacuolar changes; COX-negative fibers were also present. The time course could support a main role for capecitabine, which may have some neurotoxic effects (more frequently central), but a detrimental interaction between the two drugs cannot be ruled out and further studies are needed. [Copyright &y& Elsevier]

Abstract: Background: Hydroxy-methyl-glutaryl Co-A reductase (HMGCR) inhibitors or statins are a well recognized cause of a variety of skeletal myopathic effects which generally resolve on stopping the medication. Recent reports, however, suggest that statins are associated with a unique autoimmune myopathy wherein symptoms persist or even progress after statin discontinuation and require immunosuppressive therapy. We performed a systematic review to examine the association of statins with inflammatory (dermatomyositis/polymyositis) and necrotizing myopathies. Methods: We searched PubMed, Ovid and Scopus for English language articles addressing statin associated inflammatory and necrotizing myopathies. Given the paucity of cases, we extended the search to include articles in all languages. Results: The search yielded 14 articles reporting a possible association of statins with inflammatory myopathies describing 10 cases of polymyositis and 14 cases of dermatomyositis, and 4 articles reporting a possible association of statins with necrotizing myopathies describing 63 cases. One study identified a unique antibody directed against HMGCR in patients with necrotizing myopathy. Systemic immunosuppressive therapy was required in majority of these cases for resolution of symptoms. Conclusion: Statins have recently been associated with a variety of inflammatory myopathies including polymyositis, dermatomyositis, and a necrotizing myopathy. The association of statins with necrotizing myopathy is strengthened by the discovery that the serum of some of these patients contains an anti-HMGCR antibody. This suggests that statins can cause or unmask an immune mediated myopathy. [Copyright &y& Elsevier]

Abstract: The idiopathic inflammatory myopathies (IIM) encompass a heterogeneous group of rare disorders that present with acute, subacute, or chronic muscle weakness. Besides overlapping clinical manifestations, polymyositis, dermatomyositis and autoimmune necrotizing myopathy may be associated with cancer or collagen vascular disease, and respond generally well to immunosuppressive therapy. However, these 3 IIM are divergent from the histopathological and pathogenetic standpoints. On the other hand, inclusion body myositis (IBM), the most common IIM in the elderly, is clinically, histopathologically and pathogenetically distinct. IBM is also refractory to all currently available therapies. In this manuscript, we depict advances in our knowledge of the IIM, with emphasis on clinical presentation, associated conditions, laboratory features, electrophysiology, muscle histopathology, pathogenesis, and therapy [Copyright &y& Elsevier]

Abstract: Necrotizing myopathy is an unusual and severe form of paraneoplastic myopathy in which inflammation is minimal or absent. We report two cases of necrotizing myopathy which demonstrated significant response to intravenous immunoglobulin (IVIG) (one in spite of tumor progression). A third case represents the first association of anti-signal recognition particle (anti-SRP) syndrome with large-cell lung cancer. These cases highlight the role of histopathologic diagnosis in directing the treatment of paraneoplastic myopathy, and the role for IVIG in treatment of the syndrome. [Copyright &y& Elsevier]

Abstract: Anti-SRP (signal recognition particle) positive necrotizing myopathy is commonly not associated with neoplasms. We demonstrate two histologically confirmed cases with unusual manifestations of anti-SRP positive necrotizing myopathy. A 65-year-old man presented with rapidly progressing weakness and mild difficulties in swallowing and speaking. Screening for underlying disorders revealed a moderately differentiated renal adenocarcinoma. The muscular symptoms partially improved after tumor nephrectomy and prednisone treatment. However, the patient developed pulmonary metastases and died of the sequelae of pneumonia 11 months after the diagnosis of renal cancer. The second patient developed rapidly complete external ophthalmoplegia, severe bulbar dysarthrophonia and dysphagia, bilateral facial palsy, loss of patellar and ankle jerk reflexes, and severe symmetrical tetraparesis of both proximal and distal muscles. CSF showed mildly increased protein levels, neurography axonal impairment of motor nerves. Screening revealed no evidence for infections, ganglioside antibodies, and carcinoma. MRI was normal. The disease course suggested an overlap syndrome of Miller-Fisher-syndrome, axonal Guillain-Barré-syndrome and Bickerstaff brainstem encephalitis. In conclusion SRP antibodies might be found in necrotizing myopathies associated with autoimmune mediated overlap syndromes and neoplasms. The pathomechanism is not clear. Any otherwise unexplained evidence of necrotizing myopathy should prompt the screening for SRP antibodies. [Copyright &y& Elsevier]