Statin-associated autoimmune myopathy and anti-HMGCR autoantibodies

Clinical Significance of Uncommon, Non-Clinical, and Novel Autoantibodies

Autoantibodies are a common mark of autoimmune reaction and their identification in the patients' serum, cerebrospinal fluid, or tissues is generally believed to represent diagnostic or prognostic biomarkers of autoimmune diseases or autoinflammatory conditions. Traditionally, autoantibody testing is an important part of the clinical examination of suspected patients, and in the absence of reliable T cell tests, characterization of autoantibody responses might be suitable in finding causes of specific autoimmune responses, their strength, and sometimes commencement of autoimmune disease. Autoantibodies are also useful for prognostic stratification in clinically diverse groups of patients if checked repeatedly. Antibody discoveries are continuing, with important consequences for verifying autoimmune mechanisms, diagnostic feasibility, and clinical management. Adding newly identified autoantibody-autoantigen pairs to common clinical laboratory panels should help upgrade and harmonize the identification of systemic autoimmune rheumatic disorders and other autoimmune conditions. Herein, we aim to summarize our current knowledge of uncommon and novel autoantibodies in the context of discussing their validation, diagnostic practicability, and clinical relevance. The regular updates within the field are important and well justified.

Genetic Determinants of Response to Statins in Cardiovascular Diseases

Despite extensive efforts to identify patients with cardiovascular disease (CVD) who could most benefit from the treatment approach, patients vary in their benefit from therapy and propensity for adverse drug events. Genetic variability in individual responses to drugs (pharmacogenetics) is considered an essential determinant in responding to a drug. Thus, understanding these pharmacogenomic relationships has led to a substantial focus on mechanisms of disease and drug response. In turn, understanding the genomic and molecular bases of variables that might be involved in drug response is the main step in personalized medicine. There is a growing body of data evaluating drug-gene interactions in recent years, some of which have led to FDA recommendations and detection of markers to predict drug responses (e.g., genetic variant in VKORC1 and CYP2C9 genes for prediction of drug response in warfarin treatment). Also, statins are widely prescribed drugs for the prevention of CVD. Atorvastatin, fluvastatin, rosuvastatin, simvastatin, and lovastatin are the most common statins used to manage dyslipidemia. This review provides an overview of the current knowledge on the pharmacogenetics of statins, which are being used to treat cardiovascular diseases.

The Role of Environmental Factors in the Development of Idiopathic Inflammatory Myopathies: a Narrative Review

PURPOSE OF REVIEW

This review aims to evaluate recent findings on the role of environmental factors in the development and clinical presentation of idiopathic inflammatory myopathies (IIMs).

RECENT FINDINGS

A targeted literature review was conducted to identify reports relevant to the association between environmental factors and IIMs published over the past three years. There has been an increasing number of publications dealing with the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination with the development of IIMs, highlighting the significant role of the antiviral immune response in the pathogenesis of the disease. Traditional environmental factors associated with the pathogenic process of IIM subclassifications included drugs such as statins and immune checkpoint inhibitors, ultraviolet radiation, smoking, air pollutants, and vitamin D deficiency. Correlations of seasonality and residence with the onset of certain IIM subtypes suggest a potential role of environmental triggers in the pathogenic process. An interplay between genetic predisposition and various environmental factors might contribute to the development of IIMs as well as the heterogeneous clinical and serological presentation of IIMs. The growing evidence on the role of environmental factors in the development of IIMs provides important clues to elucidate the pathophysiology of these disease entities. The mechanisms underlying the interactions between genetic predisposition and environmental factors should be investigated in the future.

Environmental exposures as risk factors for idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare autoimmune diseases, with increasing incidence rates observed in the recent years. The pathogenesis of IIM remains not fully understood, and the interaction of genetic and environmental factors is suspected. It is unclear whether the observed upward trend in the IIM incidence is solely due to improved access to effective diagnostics or perhaps due to increased exposure to external risk factors. The PUBMED database was thoroughly searched for articles describing environmental exposures potentially triggering the onset of IIM. The article summarizes the current knowledge available on this subject, taking into account various environmental factors, including among others UV radiation, infectious agents with SARS-CoV-2, inhaled particles, or iatrogenic effects. Limitations and unmet needs requiring further studies were highlighted.

Statin-Associated Autoimmune Myopathy Masquerading As Recurrent Falls in an Older Adult

Statins are widely prescribed in clinical practice. Statin-induced myopathy is relatively common, benign, and resolves after statin withdrawal. However, statin-associated autoimmune myopathy is an exceptionally rare and devastating complication that can occur any time after statin initiation. It is characterized by persistent muscle weakness and elevated creatine kinase levels that persist after statin withdrawal. Herein, we present a challenging case of a statin-associated autoimmune myopathy that developed after a decade of atorvastatin use that resulted in debilitating weakness. It is important to recognize cases of myopathies wherein statin discontinuation and aggressive immunosuppressive therapy can reduce morbidity and mortality.

A Case of Statin-Associated Autoimmune Myopathy: Management and Treatment

Elevated lipid panels are associated with an increased risk of cardiovascular disease. Management of heart disease with lipid lowering agents play a vital role in medicine. Statins are one group of medications that are widely utilized in the medical field to decrease the risk of atherosclerotic disease. Statins work by inhibiting the hepatic enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). Although statins are one of the most effective drugs for secondary and primary prevention of heart disease, they are not without risks and side effects such as hepatotoxicity and myopathy. We present a case of a male patient who developed progressively worsening muscle weakness and elevated muscle enzyme markers upon initiation of a statin. His symptoms persisted despite a trial of an alternative statin and subsequent discontinuation of all statin medications. A multitude of possible etiologies were considered and ranged from infectious, autoimmune, cancerous, to congenital in nature. Environmental factors, such as exposure to medications or toxins, were also considered as one of the possible precipitating factors. The association between his statin consumption and muscle weakness were not easily apparent at first. He required further workup including physical examination, electromyography, panel of myositis antibodies, and muscle biopsy. After clinical suspicion and elevated antibodies to HMGCR beyond the normal limit, he was discovered to have statin-associated autoimmune myopathy. The patient improved with the treatment of immunosuppressive agent's prednisone and methotrexate.

Anti-HMGCR myopathy: barriers to prompt recognition

Anti-HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase) myopathy is an immune-mediated necrotising myopathy. Atypical presentations hinder its recognition and its prompt treatment. We present two patients with atypical clinical or pathological features. A 45-year-old woman had an asymptomatic serum creatine kinase (CK) of ~10 000 IU/L and muscle biopsy showing minimal changes. She then developed slowly progressive proximal weakness, diagnosed as limb-girdle muscular dystrophy but with negative genetics. Twelve years later, now with severe proximal weakness, her MR scan of muscle showed diffuse asymmetrical fatty degeneration, with conspicuous hyperintense STIR signal abnormalities. HMGCR antibodies were positive and she partially improved with immunosuppression. The second patient developed slowly progressive proximal limb weakness with a high serum CK (~4000 IU/L); muscle biopsy showed a lymphocyte infiltrate with angiocentric distribution suggesting vasculitis. Serum HMGCR antibodies were positive. Anti-HMGCR myopathy can present as a slowly progressive myopathy with atypical pathology. HMGCR antibody screening is indicated for people with suspected limb-girdle muscular dystrophy or atypical inflammatory muscle conditions.

Statin-associated immune-mediated necrotizing myositis in Native Americans

OBJECTIVES

Statin-associated immune-mediated necrotizing myopathy (IMNM) and idiopathic inflammatory myositis (IIM) are myopathies with overlapping features. This study compared the manifestations of IMNM to IIM in Native Americans.

METHOD

Twenty-one Native American patients with inflammatory myopathy (IM) were characterized as to diabetes mellitus, hyperlipidaemia, statin exposure, myopathy diagnosis, muscle histology, autoimmune and myositis-specific autoantibodies, therapy and outcome.

RESULTS

IM consisted of 52.4% IMNM, 42.9% IIM and 4.8% metabolic myopathy. IMNM vs IIM patients were older [61.6 years (s.d. 9.8) vs 39.8 (14.3)], diabetes mellitus (100% vs 55.6%), hyperlipidaemia (100% vs 33.3%), statin-exposure (100% vs 22.2%), creatine kinase [CK; 11 780 IU (s.d. 7064) vs 1707 (1658)], anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) antibodies (85.7% vs 11.1%) and necrotizing IM (81.8% vs 11.1%), but shorter disease duration [26.2 months (s.d. 395) vs 78.4 (47.9)], RP (9.1% vs 55.6%), cutaneous manifestations (0% vs 55.6%), ANA (18.2% vs 66.7%) or any autoantibody (18.2% vs 88.9%) (all P < 0.05). MRI abnormalities, histologic IM, myositis-specific autoantibodies, pulmonary hypertension, oesophageal dysfunction, interstitial lung disease, disability and persistently elevated CK were similar. IMNM vs IIM was treated more with IVIG (72.7% vs 11.1%; P = 0.009) and less with antimetabolites (45.5% vs 88.9%; P = 0.05) and rituximab (18.2% vs 55.6%; P = 0.09).

CONCLUSIONS

IMNM may occur in Native Americans and is associated with diabetes mellitus, hyperlipidaemia, statin use and older age and is characterized by marked CK elevation, necrotizing myopathy and anti-HMGCR antibodies with few cutaneous or vascular manifestations.

Statin-related Muscle Toxicity: An Evidence-based Review

The efficacy of statins in the primary and secondary prevention of cardiovascular disease has been proven beyond doubt. The number needed to treat to prevent one cardiovascular event is 1 in 30 over 10 years, and the number needed to treat for secondary prevention is much lower. However, a recent study demonstrated that only 68% of eligible patients are on statin therapy. Moreover, there seems to be a reluctance to escalate statin doses due to the fear of adverse effects. The adverse effects that worries patients and their physicians most frequently are those related to muscular symptoms. N-of-1 trial evidence suggests that muscular symptoms attributed to statins are often caused by the nocebo effect. This article aims to provide a structured, evidence-based approach to suspected statin-related muscle toxicity.

[Subacute Flaccid Tetraparesis]

Subacute Flaccid Tetraparesis Abstract. The patient presented herself with a subacute flaccid tetraparesis. After clinical examination, laboratory analysis, EMG, MRI and muscle biopsy we diagnosed a statin-associated immune-mediated necrotizing myopathy. Neurorehabilitation and prednisolone therapy as well as immunomodulatory therapy with azathioprine did not result in remission. After two cycles of Privigen®, the patient was almost symptom-free and no longer restricted in everyday life; the CK fell to 400U/l.

Incidence and Prevalence of Immune-mediated Necrotizing Myopathy in Adults in Olmsted County, Minnesota

INTRODUCTION/AIMS

Immune-mediated necrotizing myopathy (IMNM) is considered a rare subtype of the immune-mediated myopathies, but its incidence and prevalence are unknown. This study aimed to determine the incidence and prevalence of IMNM in the adults in Olmsted County, Minnesota.

METHODS

We identified adult patients with IMNM defined by the 2016 European Neuromuscular Centre diagnostic criteria among Olmsted County, Minnesota, residents over a 20-year period RESULTS: Seven patients fulfilled the inclusion criteria. Six patients were tested for IMNM antibodies: 4 were anti 3-Hydroxy-3-Methylglutaryl-CoA Reductase (HMGCR)-positive, 1 was anti-signal recognition particle (SRP)-positive and 1 was seronegative. The incidence of IMNM during 2010-2019 was 8.3 per million person-years. The prevalence of IMNM in 2010 was 1.85 per 100,000 people ≥50 years. Median age at symptom onset was 64 years (range: 52-86) and median time from symptom onset to diagnosis was 3 months (range <1-156). Statin use among anti-HMGCR IMNM patients, but not the entire IMNM cohort, was higher than in controls (P=0.024). Two IMNM patients developed cancers. The incidence of malignancy in IMNM was not higher than that of the general population. Treatment outcome was favorable in all patients except for 1 with delayed treatment and one with insufficient therapy. Among 3 deceased patients, 1 died from cancer while 2 died from IMNM-related cardiorespiratory complications.

DISCUSSION

IMNM is a rare disease. Its prevalence is one tenth that of inclusion body myositis in Olmsted County, Minnesota. IMNM patients in our cohort were not at higher risk for developing cancer.

Rituximab use for refractory anti-HMGCR immune-mediated necrotizing myopathy: A case report

Immunosuppression is the cornerstone therapy for anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGCR) myopathy. Typical immunosuppressants such as corticosteroids, methotrexate, and azathioprine have been used in conjunction with removal of the offending agent, yet the use of rituximab is more limited in this type of myopathy. Reported here is a case of a patient who responded well to rituximab (RTX) after the standard immunosuppressants had failed. This case illustrates the importance of further studies to evaluate the role of RTX in anti-HMGCR myopathy.

[Atypical arthritis of the hands : Collagenosis-part 1]

BACKGROUND

Systemic lupus erythematosus (SLE) is a gynecotropic autoimmune vasculitis with manifestations in various organ systems including the skin, internal organs, and joints.

OBJECTIVE

Presentation of the atypical arthritis patterns of the hands in SLE as the most common autoimmunologic rheumatologic disease from the group of collagenoses in the context of clinical and serological findings and considering the classification criteria of the American College of Rheumatology compared to rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

MATERIALS AND METHODS

Narrative review based on the current literature on the subject from a radiological and rheumatological point of view.

RESULTS

In 80-90% of all SLE cases, hand joint manifestations can be detected, mostly in the form of non-erosive oligo- or polyarthralgias with the picture of so-called luxation arthropathies and with the pattern of a so-called Jaccoud's or Lupus' syndrome, which are accompanied by "carpal instability" in 15% of cases. In association with an antiphospholipid antibody syndrome, ischemic osteonecrosis may occur in 5-50% of SLE, predominantly in weight-bearing areas of the skeleton, and less frequently in the carpal bones or metacarpal heads. The rare rhupus syndrome comprises patients with overlap of RA and SLE features.

CONCLUSIONS

Due to the heterogeneity of the symptoms and the often individually very different courses, the diagnosis of SLE can be difficult. Since new drug therapy concepts have significantly increased the 5‑year survival rates of SLE from 0% in the 1950s to 70-90% in recent decades, a timely and definite diagnosis is necessary, to which radiologists can also contribute by correctly classifying the image morphological SLE arthritis patterns in the hands.

Statin-Induced Myopathy: Translational Studies from Preclinical to Clinical Evidence

Statins are the most prescribed and effective drugs to treat cardiovascular diseases (CVD). Nevertheless, these drugs can be responsible for skeletal muscle toxicity which leads to reduced compliance. The discontinuation of therapy increases the incidence of CVD. Thus, it is essential to assess the risk. In fact, many studies have been performed at preclinical and clinical level to investigate pathophysiological mechanisms and clinical implications of statin myotoxicity. Consequently, new toxicological aspects and new biomarkers have arisen. Indeed, these drugs may affect gene transcription and ion transport and contribute to muscle function impairment. Identifying a marker of toxicity is important to prevent or to cure statin induced myopathy while assuring the right therapy for hypercholesterolemia and counteracting CVD. In this review we focused on the mechanisms of muscle damage discovered in preclinical and clinical studies and highlighted the pathological situations in which statin therapy should be avoided. In this context, preventive or substitutive therapies should also be evaluated.

Atorvastatin-Induced Necrotizing Myopathy and its Response to Combination Therapy

Atorvastatin is the most commonly used statin medication to decrease cholesterol levels and prevent atherosclerosis. Myopathy is a reported side effect of atorvastatin which can happen even after more than six months after starting the medication. The side effect on the muscle tissue can range from simple reversible myalgia to respiratory muscle compromise. Here we present a 46-year-old male who presented with myopathy after taking atorvastatin for two years. Biopsy proved immune-mediated necrotizing myopathy which responded to a combination of Rituximab and intravenous immunoglobulin therapy.

Statin-Associated Necrotizing Myopathy: A Feared Complication

Statins are a group of frequently-prescribed drugs with proven cardiovascular risk-benefit. The most common adverse effects include weakness and myalgias. However, prescribers need to be aware of a less common complication, statin-associated necrotizing myopathy, which can occur at any time during the treatment course and has been found to be <0.1% of adverse effects. High suspicion is warranted when patients taking statins develop weakness and myalgia. Increased risk of muscle injury has been observed when using gemfibrozil in combination with statins and should be avoided. We present a case of an elderly male with chronic use of combination lipid-lowering agents who initially presented with proximal weakness. He was diagnosed with statin-associated necrotizing myopathy and subsequently developed rapid end-stage renal disease in the setting of severe rhabdomyolysis. The case report discusses the work-up of proximal muscle weakness with focus on the importance of early recognition and prompt management of rhabdomyolysis to avoid life-threatening complications.

Pathophysiological mechanisms of statin-associated myopathies: possible role of the ubiquitin-proteasome system

BACKGROUND

Statins are the cornerstone of pharmacotherapy for atherosclerotic cardiovascular disease. While these drugs are generally safe, treatment adherence is not optimal in a considerable proportion of patients because of the adverse effects on skeletal muscles in the forms of myopathy, myalgia, muscular pain, nocturnal muscle cramping, weakness, and rare rhabdomyolysis.

METHODS

For the purpose of this narrative review, we searched for the literature suggesting the involvement of the ubiquitin-proteasome system in the development of statin-induced myopathy.

RESULTS

Statins have been shown to up-regulate the expression of the muscle-specific ubiquitin-proteasome system as the major non-lysosomal intracellular protein degradation system. It has been postulated that statins may provoke instability in the myocyte cell membrane when subjected to eccentric exercise stress, triggering activation of intracellular proteolytic cascades and changes in protein degradation machinery. This is accompanied by the up-regulation of a series of genes implicated in protein catabolism, in addition to those of the ubiquitin-proteasome system.

CONCLUSIONS

Based on the available literature, it seems that the involvement of ubiquitin-proteasome system is potentially implicated in the pathophysiology of statin-induced myopathy.

Statin use in patients with non-HMGCR idiopathic inflammatory myopathies: A retrospective study

Background

Statins are the most widely used lipid lowering therapies which reduce cardiovascular risk, but are associated with muscular adverse events (AEs). Idiopathic inflammatory myopathies (IIM) are autoimmune diseases of the muscle with higher risk of cardiovascular disease. More data is needed regarding statin safety in patients with intrinsic muscle disease such as IIM.

Hypothesis

Statins are tolerated in patients with IIM without leading to significant increase in muscular AEs.

Methods

Statin use was retrospectively examined in a longitudinal IIM cohort. Safety analysis included assessment of muscular and nonmuscular AEs by chart review. IIM patients receiving a statin during the cohort follow‐up period were matched to IIM patients not receiving a statin for comparative analysis of longitudinal outcomes.

Results

33/214 patients had a history of statin use. 63% started for primary prevention, while others were started for clinical ASCVD events, vascular surgery, IIM related heart failure, and cardiac transplantation. A high intensity statin was used in nine patients with non‐HMGCR myositis, and tolerated in 8/9 patients. Statin related muscular AE was noted in three patients. There were no cases of rhabdomyolysis, or statin related nonmuscular AEs in a median observation period of 5 years. In patients newly started on statins during cohort follow‐up (n = 7) there was no change in disease activity after statin initiation. Long term outcomes were not different between statin and nonstatin IIM control groups.

Conclusion

Statins were well tolerated in patients with non‐HMGCR positive IIM. Given the accelerated atherosclerotic risk in IIM patients, further prospective studies of statin safety in IIM patients are warranted.

Immune mediated necrotizing myopathy: A rare complication of statin therapy

Immune mediated necrotizing myopathy (IMNM) is part of the inflammatory myopathies group of diseases and presents with muscle weakness, myalgias and elevated serum creatine phosphokinase (CPK). Statin-induced IMNM is a rare complication. We present a patient with IMNM secondary to simvastatin use. The patient presented with proximal myopathy, dysphagia, and elevated creatinine kinase levels, and was subsequently found to have anti-3- hydroxy-3-methylglutaryl-CoA reductase (HMGCR) autoantibodies with a necrotizing process on muscle biopsy. This patient’s case was further complicated by sequelae of multiple disease processes, ultimately leading to deterioration of his health.

Statin-induced necrotising autoimmune myopathy and autoimmune hepatitis presenting with dysphagia

Statin-induced necrotising autoimmune myopathy (SINAM) is a rare disease characterised by proximal muscle weakness and elevated creatine kinase levels that is usually in the thousands. Anti-3-hydroxy-3-methyl glutaryl co-enzyme A reductase (HMGCR) antibodies are associated with SINAM. Autoimmune hepatitis (AIH) is an inflammatory disease of the liver that is usually of unknown aetiology but can also be associated with concurrent extrahepatic autoimmune disorders. We are reporting a case of biopsy proven AIH associated with SINAM in a patient presenting with oropharyngeal dysphagia. The patient had elevated anti-HMGCR antibodies and anti-smooth muscle antibodies. SINAM and AIH were confirmed by muscle biopsy and liver biopsy, respectively. The patient had complete resolution of his symptoms and complete normalisation of his liver function tests after 6 months of the treatment.

Necrotizing Autoimmune myopathy: A case report on statin induced rhabdomyolysis requiring immunosuppressive therapy

Statins can cause a wide spectrum of muscular adverse effects ranging from asymptomatic elevation of Creatine Kinase (CK), myalgia and exercise intolerance to rhabdomyolysis. Most of these effects generally resolve on stopping the medication. However, statins can be associated with a unique autoimmune myopathy wherein symptoms persist or even progress after statin discontinuation and require immunosuppressive therapy. The case presented is a 60-year-old woman who was on statin treatment for a period of 2 years. She developed muscle weakness with a limb girdle distribution. She had persistent elevation of CK even after discontinuation of statin therapy. EMG done revealed irritable myopathy and muscle biopsy showed necrosis without inflammation. She subsequently tested positive for anti-3-hydroxy-3-methylglutaryl-coenzyme A (anti-HMG CoA) antibody which is found to be present in patients with statin-associated necrotizing autoimmune myopathy. Patient was started on steroid without much improvement in her symptoms. After a month of follow up, her upper extremity strength was back but lower extremity continued to be weak which prompted us to start her on Methotrexate and Azathioprine. Like our patient, there are rare subgroup of patients with an immune-mediated necrotizing myopathy that does not improve after discontinuation of the drug and requires aggressive treatment with immunosuppressive agents. Awareness and early recognition of this disease is very important in patients who continue to have CK elevation and weakness after discontinuation of statin therapy.

Anti-HMGCR myopathy presenting with acute systolic heart failure

Necrotising autoimmune myopathy (NAM) is an immune-mediated myopathy that may be associated with statin use, malignancy or an autoimmune connective tissue disease, but it can also be idiopathic. Anti-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) myopathy is an extremely rare side effect of statin use, occurring in approximately 2-3 out of every 100 000 patients who use statins. Patients typically present with subacute proximal muscle weakness and creatine kinase levels >10 times the upper limit of normal. The diagnosis is suggested by muscle biopsy showing necrotic fibres with minimal inflammation along with positive anti-HMGCR antibodies. Treatment nearly always requires multiple immunosuppressive agents, the earlier use of which is associated with improved outcomes. Reports of statin-induced NAM leading to heart failure are limited. We present the case of a 69-year-old woman with statin-induced NAM who presented with acute systolic heart failure. Early initiation of high-dose corticosteroids and IVIG resulted in significant improvement in her symptoms.

Disease Specific Autoantibodies in Idiopathic Inflammatory Myopathies

Idiopathic inflammatory myopathies represent still a diagnostic and therapeutic challenge in different disciplines including neurology, rheumatology, and dermatology. In recent years, the spectrum of idiopathic inflammatory myopathies has been significantly extended and the different manifestations were described in more detail leading to new classification criteria. A major breakthrough has also occurred with respect to new biomarkers especially with the characterization of new autoantibody-antigen systems, which can be separated in myositis specific antibodies and myositis associated antibodies. These markers are detectable in approximately 80% of patients and facilitate not only the diagnostic procedures, but provide also important information on stratification of patients with respect to organ involvement, risk of cancer and overall prognosis of disease. Therefore, it is not only of importance to know the significance of these markers and to be familiar with the optimal diagnostic tests, but also with potential limitations in detection. This article focuses mainly on antibodies which are specific for myositis providing an overview on the targeted antigens, the available detection procedures and clinical association. As major tasks for the near future, the need of an international standardization is discussed for detection methods of autoantibodies in idiopathic inflammatory myopathies. Furthermore, additional investigations are required to improve stratification of patients with idiopathic inflammatory myopathies according to their antibody profile with respect to response to different treatment options.

Autoimmune necrotizing myopathy after statin discontinuation

We report a case of autoimmune necrotizing myopathy related to statin use in a 70-year-old woman who came to the hospital because of progressive lower extremity weakness. Laboratory, electromyography and muscle biopsy results were consistent with autoimmune necrotising myopathy. The patient was treated with intravenous immunoglobulin with improvement in muscle strength.

Immune-mediated necrotising myopathy: A critical review of current concepts

Immune-mediated necrotising myopathy (IMNM) is a relatively recently described form of idiopathic inflammatory myopathy (IIM) that is characterised by progressive proximal weakness and few extra-muscular manifestations. Prominent myonecrosis, muscle fibre regeneration and a relative paucity of intramuscular lymphocytes are seen histologically. Immunological mechanisms are believed to underpin the pathogenesis, and intense immunotherapy is frequently required. Disease is often severe and neuromuscular recovery may be poor. Recently there has been an impressive international research effort to understand and characterise this emerging condition, although much remains unknown. Significant advances in the field include the discovery of specific autoantibodies, increased understanding of the risk factors, clinical characteristics and treatment options owing to a wealth of observational studies, and the development of novel classification criteria. Herein we review the current evidence regarding the pathophysiology, clinical presentation, histological features and serological profiles associated with this condition. Diagnostic approaches are discussed, including the role of muscle MRI and antibodies targeting 3‑hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and signal-recognition peptide (SRP), and a review of current treatment recommendations is provided.

Autoimmune Myopathies: Updates on Evaluation and Treatment

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.

Amyotrophic Lateral Sclerosis Associated with Statin Use: A Disproportionality Analysis of the FDA's Adverse Event Reporting System

INTRODUCTION

Apparent elevations in reporting of amyotrophic lateral sclerosis (ALS)-like conditions associated with statin use have been previously described from data obtained via US and European databases.

OBJECTIVE

The aim of this study was to examine US FDA Adverse Event Reporting System (FAERS) data to compare reporting odds ratios (RORs) of ALS and ALS-like conditions between statins and other drugs, for each statin agent.

METHODS

We assessed for disproportional rates of reported ALS and ALS-related conditions for each statin agent separately by using the ROR formula. FAERS data were analyzed through September 2015.

RESULTS

RORs for ALS were elevated for all statins, with elevations possibly stronger for lipophilic statins. RORs ranged from 9.09 (6.57-12.6) and 16.2 (9.56-27.5) for rosuvastatin and pravastatin (hydrophilic) to 17.0 (14.1-20.4), 23.0 (18.3-29.1), and 107 (68.5-167) for atorvastatin, simvastatin, and lovastatin (lipophilic), respectively. For simvastatin, an ROR of 57.1 (39.5-82.7) was separately present for motor neuron disease.

CONCLUSION

These findings extend previous evidence showing that significantly elevated ALS reporting extends to individual statin agents, and add to concerns about potential elevated occurrence of ALS-like conditions in association with statin usage.

Effect of L-carnitine on the skeletal muscle contractility in simvastatin-induced myopathy in rats

Background

Statins therapy is effective in the prevention of cardiovascular events. However, its use is associated with skeletal muscle myopathy, which may be severe enough to discontinue statin therapy, thus exposing patients to more morbidity and mortality. This study was conducted to assess the effect of L-carnitine on the skeletal muscle contractility in a rat model of statin-induced myopathy and to clarify its possible mechanisms.

Methods

Twenty-one female Sprague Dawley rats were used throughout this study. The rats were divided into the normal control group, statin-induced myopathy group and statin/L-carnitine-treated group. The assessment of gastrocnemius muscle contractility, plasma creatine kinase (CK) levels and oxidative stress markers (malondialdehyde, reduced glutathione) was also carried out done.

Results

The results of the current study suggest that simvastatin decreased the skeletal muscle mass and altered the muscle contractile properties. It also significantly increased plasma CK level and induced a state of oxidative stress state (high MDA, low GSH). Meanwhile, concurrent L-carnitine significantly reduced statin-induced myopathy and improved the oxidative stress markers and skeletal muscle contractile parameters.

Conclusions

Statin myopathy is postulated to be due to mitochondrial dysfunction, cellular oxidative stress, induction of apoptosis, reduction in the expression of chloride channel and its related conductance, in addition to the alteration of Ca2+ homeostasis. L-carnitine has an antioxidant effect, reduces skeletal muscle atrophy and improves the skeletal muscle contractility in simvastatin-induced myopathy.

Statin-naïve anti-HMGCR antibody-mediated necrotizing myopathy in China

This study aimed to clarify the phenotypes and therapeutic responses of statin-naïve anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibody-mediated necrotizing myopathy. Anti-HMGCR antibodies were tested with ELISA methodology in the sera sample of 98 patients meeting the idiopathic inflammatory myopathy criteria and with negative anti-signal recognition particle (SRP) antibody. Twenty-one statin-naïve patients with anti-HMGCR antibody were detected (21.4%), with onset age from 6 to 67 years old. Proximal weakness and neck flexion weakness was the core neurological feature. The average maximal creatine kinase (CK) level was 7968.6 ± 4408.7U/L. Muscle MR imaging showed edema (88.2%), moderate or severe fatty replacement (70.6%) and muscle atrophy (88.2%) in lower limbs. Fatty replacement was significantly more prominent in the medial and posterior musculature than the anterior musculature (p = 0.0013). Seven (33.3%) patients were treated with mono-glucocorticoid, and thirteen (61.9%) patients needed adjuvant immunosuppressant. Eight (38.1%) patients experienced symptom relapse. The early-onset patients (<50 years old) were found with higher CK levels, shorter duration course, poorer response to adjuvant immunosuppressant and more recurrent weakness than the late-onset patients (≥50 years old). As a conclusion, Statin-naïve anti-HMGCR antibody-mediated necrotizing myopathy may not be rare. Compared with late-onset statin-naïve patients with anti-HMGCR antibody-mediated necrotizing myopathy, early-onset patients presented severer clinical features and worse therapeutic responses.

Muscle Damage Due to Fusidic Acid-Statin Interaction: Review of 75 Cases From the French Pharmacovigilance Database and Literature Reports

BACKGROUND/AREA OF UNCERTAINTY

Statins, which reduce cardiovascular risk in both primary and secondary prevention, are one of the most widely prescribed therapeutic classes in the world. Usually well-tolerated, statin-associated muscle symptoms are a well-known adverse effect. Fusidic acid (FA) is a bacteriostatic antibiotic of interest in the treatment of methicillin-resistant Staphylococcus aureus infections. Cases of rhabdomyolysis, sometimes fatal, have been reported after coprescription of FA and a statin.

DATA SOURCES/AREA OF UNCERTAINTY

We studied 75 cases of muscle damage related to interaction between FA and a statin reported in the French national pharmacovigilance database (43 cases) and from a literature review (32 cases).

RESULTS

Cases were mostly men (72.5%), often overweight (mean body mass index: 29.4). The most commonly reported statins were atorvastatin (60%), simvastatin (22.7%), and rosuvastatin (8.0%). Muscle disorders appeared on average 30 days after initiation of FA. Symptoms were muscle weakness (82%), dark urine (71%), and myalgia (61%). Mean creatine kinase level at diagnosis was 43,890 UI/mL, and acute renal injury occurred more than half of the cases. Outcome was fatal in 22% of cases and 28% kept sequelae at the end of the follow-up (54 days).

CONCLUSIONS

Muscle damage induced by interaction between FA and statin is a potentially life-threatening complication, leading to contraindication of this association in France. This is to be reminded especially because FA is about to get FDA approval and should soon be available in the United States.

HMGCR-associated myositis: a New Zealand case series and estimate of incidence

Statins are one of the most commonly prescribed drugs in New Zealand, with 525 772 or 16.5% of the adult New Zealand population prescribed a statin between June 2013 and July 2014. While generally well-tolerated, statins are known to cause a range of muscle-related side effects, ranging from myalgia to life-threatening rhabdomyolysis. Recently, it has been recognised that in rare instances, statins can induce an immune-mediated necrotising myositis with antibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), the enzymatic target of statins. In 2014, anti-HMGCR antibody testing was introduced to Canterbury Health Laboratories (CHL), with this being the only laboratory in New Zealand performing this test during the period of this case series. This article describes an index case and characterises the clinical features of a subsequent 12-month series. From this series, we estimated the yearly incidence of HMGCR-associated myositis at 1.7/million/year or ~1/90 000 New Zealand statin users.

A severe myopathy case in aged patient treated with high statin dosage

Statins (S) are widely used drugs for cardiovascular prevention however their utilization may cause a various grade of muscle toxicity. Sometime S discontinuation alone is not sufficient to revert muscle injury and this can evolve in serious inflammatory muscle disease. In this case immunosuppressive medications are required to achieve remission. This case report describes a patient who developed rhabdomyolysis after recent S treatment initiation and the diagnostic work up have lead to the diagnosis of necrotizing autoimmune myopathy (NAM). We believe that the clinical case described here is a useful report of this rare toxicity and we aim to highlight the importance of its prompt recognition and treatment.

Detection of autoantibodies to 3-hydroxy-3-methylglutaryl-coenzyme a reductase by ELISA in a reference laboratory setting

BACKGROUND

We investigated the performance of an ELISA for the detection of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) IgG antibodies in immune-mediated necrotizing myopathies (IMNM).

METHODS

Patients positive for HMGCR antibodies (n=61) or negative (n=78) by protein immunoprecipitation (IP), and healthy controls (n=100) were used to evaluate the ELISA. Unique consecutive serum samples (n=155) received at ARUP Laboratories for HMGCR IgG testing by ELISA were also investigated and analysed for serum muscle enzymes (aldolase, creatine kinase, and myoglobin). The ELISA's sensitivity, specificity, and percentage agreement were assessed relative to IP. Correlation between specific muscle enzyme concentration and the presence of HMGCR antibody was determined.

RESULTS

Overall agreement between ELISA and IP was 93.4%. Using the IP as reference, the sensitivity and specificity of the ELISA was 95.1%, and 100%, respectively. Inter- and intra-assay coefficient of variation of the ELISA was <10.0%, and ≤15.0%, respectively. In the consecutive cohort, 21 (13.6%) samples tested positive for HMGCR IgG. Concentrations of aldolase, creatine kinase, and myoglobin were significantly higher (all p<0.0001) in patients positive for HMGCR antibodies at the time of evaluation.

CONCLUSIONS

We confirm significant reliability of HMGCR antibodies as measured by the ELISA for the evaluation of IMNM.

Statin-Associated Side Effects

Hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins are well tolerated, but associated with various statin-associated symptoms (SAS), including statin-associated muscle symptoms (SAMS), diabetes mellitus (DM), and central nervous system complaints. These are "statin-associated symptoms" because they are rare in clinical trials, making their causative relationship to statins unclear. SAS are, nevertheless, important because they prompt dose reduction or discontinuation of these life-saving mediations. SAMS is the most frequent SAS, and mild myalgia may affect 5% to 10% of statin users. Clinically important muscle symptoms, including rhabdomyolysis and statin-induced necrotizing autoimmune myopathy (SINAM), are rare. Antibodies against HMG-CoA reductase apparently provoke SINAM. Good evidence links statins to DM, but evidence linking statins to other SAS is largely anecdotal. Management of SAS requires making the possible diagnosis, altering or discontinuing the statin treatment, and using alternative lipid-lowering therapy.

Diagnostic confounders of chronic widespread pain: not always fibromyalgia

Although chronic widespread pain is the defining feature of fibromyalgia, a myriad of other conditions may present with similar pain complaint leading to misdiagnosis. Conditions that may mimic fibromyalgia may be categorized as musculoskeletal, neurological, endocrine/metabolic, psychiatric/psychological, and medication related. In this review, we examine these various conditions that should be considered in a differential diagnosis and provide direction that will help the clinician differentiate these conditions from fibromyalgia.

Introduction:

Chronic widespread pain (CWP) is the defining feature of fibromyalgia (FM), a worldwide prevalent condition. Chronic widespread pain is, however, not pathognomonic of FM, and other conditions may present similarly with CWP, requiring consideration of a differential diagnosis.

Objectives:

To conduct a literature search to identify medical conditions that may mimic FM and have highlighted features that may differentiate these various conditions from FM.

Methods:

A comprehensive literature search from 1990 through September 2016 was conducted to identify conditions characterized by CWP.

Results:

Conditions that may mimic FM may be categorized as musculoskeletal, neurological, endocrine/metabolic, psychiatric/psychological, and medication related. Characteristics pertaining to the most commonly identified confounding diagnoses within each category are discussed; clues to enable clinical differentiation from FM are presented; and steps towards a diagnostic algorithm for mimicking conditions are presented.

Conclusion:

Although the most likely reason for a complaint of CWP is FM, this pain complaint can be a harbinger of illness other than FM, prompting consideration of a differential diagnosis. This review should sensitize physicians to a broad spectrum of conditions that can mimic FM.

Neutrophil Extracellular Traps, Antiphospholipid Antibodies and Treatment

Neutrophil extracellular traps (NETs) are a network of extracellular fibers, compounds of chromatin, neutrophil DNA and histones, which are covered with antimicrobial enzymes with granular components. Autophagy and the production of reactive oxygen species (ROS) by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase are essential in the formation of NETs. There is increasing evidence that suggests that autoantibodies against beta-2-glycoprotein-1 (B2GP1) induce NETs and enhance thrombosis. Past research on new mechanisms of thrombosis formation in antiphospholipid syndrome (APS) has elucidated the pharmacokinetics of the most common medication in the treatment of the disease.

Statin-associated muscle symptoms: position paper from the Luso-Latin American Consortium

In the last two decades, statin therapy has proved to be the most potent isolated therapy for attenuation of cardiovascular risk. Its frequent use has been seen as one of the most important elements for the reduction of cardiovascular mortality in developed countries. However, the recurrent incidence of muscle symptoms in statin users raised the possibility of causal association, leading to a disease entity known as statin associated muscle symptoms (SAMS). Mechanistic studies and clinical trials, specifically designed for the study of SAMS have allowed a deeper understanding of the natural history and accurate incidence. This set of information becomes essential to avoid an unnecessary risk of severe forms of SAMS. At the same time, this concrete understanding of SAMS prevents overdiagnosis and an inadequate suspension of one of the most powerful prevention strategies of our times. In this context, the Luso-Latin American Consortium gathered all available information on the subject and presents them in detail in this document as the basis for the identification and management of SAMS.

[Not Available]

Zusammenfassung. Wir berichten über einen 79-jährigen Patienten mit einer generalisierten Muskelschwäche. Als Ursache fand sich eine bioptisch und durch anti-HMGCR-Antikörper gesicherte Statin-induzierte immunmediierte nekrotisierende Myopathie. Erst die Behandlung mit Rituximab in Kombination mit Steroiden und Azathioprin führte zu einer Besserung der Muskelschwäche.