An Unusual Case of Statin-Induced Myopathy: Anti-HMGCoA Necrotizing Autoimmune Myopathy

Unveiling the Rare Complication: Statin-Induced Immune-Mediated Necrotizing Myopathy

BACKGROUND Statin-induced necrotizing autoimmune myopathy is an exceptionally rare yet severe complication of statin therapy that may develop in individuals at any time during their exposure to statins. The development of proximal muscle weakness, muscle pain, and elevated creatine kinase (CK) levels in patients while taking statins should prompt clinical consideration of statin-induced myopathy. The pathophysiology arises from the production of auto-antibodies, which target the 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) enzyme, leading to the aggressive breakdown of myofibrils. CASE REPORT Here, we present a case of a 59-year-old woman with a medical history of dyslipidemia who developed anti-HMG-CoA reductase antibodies after taking atorvastatin. She came to the emergency department with complaints of severe proximal muscle weakness. The laboratory workup showed an elevated CK level up to 12 000 IU/L. Despite discontinuing atorvastatin, the patient's elevated CK levels persisted. The patient underwent a muscle biopsy, demonstrating myofibril necrosis. Serological analysis showed anti-HMG-CoA reductase antibodies in the patient's serum, which led to the diagnosis of immune-mediated necrotizing myopathy due to statins. The patient's statin therapy was promptly discontinued, and she was treated with a high dose of IV corticosteroids. After the patient's discharge, brief discontinuation of the corticosteroids resulted in CK elevation and a return of symptoms. This led to the second re-admission and restarting of corticosteroids until stabilization and discharge. CONCLUSIONS This case represents an important reminder for clinicians to recognize the possibility of statin-induced immune-mediated necrotizing myopathy in patients presenting with proximal muscle weakness while taking a statin, notwithstanding the rarity of this condition.

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 Report of Statin-Induced Immune-Mediated Necrotizing Myopathy Treatment Challenges

Statin-induced necrotizing autoimmune myopathy is an immune-mediated necrotizing myopathy related to the use of statins. It is a very rare disease, which usually presents with proximal muscle weakness and frank elevation in creatine kinase levels. Stopping statin and the use of immunosuppressive therapy are considered the mainstay therapy. Use of steroids in patients with inflammatory myopathy can be complicated by steroid-induced myopathy. Herein, we present a case of a 55-year-old patient with statin-induced necrotizing autoimmune myopathy based on the presence of proximal muscle weakness, magnetic resonance findings, suggestive muscle biopsy features, and positive anti-HMGCR autoantibodies. The patient was treated with triple immunosuppressive therapy with a particularly good response to intravenous immunoglobulin. This report highlights the importance of timely diagnosis and early use of combined immunosuppressive therapy to improve patients' outcome affected by this rare disease.

Efficacy and safety of statins in ethnic differences: a lesson for application in Indigenous Australian patient care

Although statins are effective in treating high cholesterol, adverse effects do occur with their use. Efficacy and tolerability vary among statins in different ethnic groups. Indigenous Australians have a high risk for cardiovascular and kidney diseases. Prescribing statins to Indigenous Australians with multi-morbidity requires different strategies to increase efficacy and reduce their toxicity. Previous studies have reported that Indigenous Australians are more susceptible to severe statin-induced myopathies. However, there is a lack of evidence in the underlying genetic factors in this population. This review aims to identify: inter-ethnic differences in the efficacy and safety of statins; major contributing factors accounting for any identified differences; and provide an overview of statin-induced adverse effects in Indigenous Australians.

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.

An overview of statin-induced myopathy and perspectives for the future

Introduction: Statins remain the most commonly prescribed lipid-lowering drug class for the treatment of atherosclerotic cardiovascular disease. Their well-recognized side effects are known as statin-associated muscle symptom (SAMS). Some advances in this field have been made in recent years, but the understanding of the mechanisms has lagged. Investigating the specific role of the anti-HMGCR autoantibody, pharmacokinetic genetic variants, characterization of the known phenotypes of statin toxicity, in relation to clinical markers of disease, is of high importance.Areas covered: We summarized currently available findings (on PubMed) related to SAMS and discussed the therapeutic approaches, risk factors, drug interactions, potential novel systems, algorithms and biomarkers for SAMS detection. CoQ10 supplementation has been suggested as a complementary approach to manage SAMS, while vitamin D levels may be useful for both the diagnosis and management.Expert Opinion/Commentary: Further studies might help to understand the easiest way to diagnose SAMS, suitable prevention and an effective non-statin therapy. This review sheds new light on the future directions in both research and clinical practice, which will help with rapid risk assessment, identification of the SAMS risk factors in order to decrease the incidence of statins' adverse effects, and the most effective therapy.

A RARE CASE OF STATIN-INDUCED NECROTIZING AUTOIMMUNE MYOPATHY

OBJECTIVE

Necrotizing autoimmune myopathy (NAM) is a rare side-effect of statin therapy. We report the case of a patient who developed statin-induced NAM with a review of the clinical presentation and management of this rare entity. The case illustrates the importance of including NAM in the differential diagnosis of persistent myopathy in a statin-exposed individual.

METHODS

A 74-year-old male was referred to endocrinology for hypercholesterolemia management in the context of a statin contraindication. He previously developed myositis and rhabdomyolysis secondary to statin therapy, but continued to have persistent proximal lower limb muscle weakness despite statin discontinuation. Rheumatologic and metabolic work-up were negative and neurologic work-up was negative except for a myopathic pattern in the glutei found on electromyography.

RESULTS

Due to the persistence of proximal myopathy despite statin discontinuation and myopathic pattern seen on electromyography, NAM was suspected and antibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase were sent and came back positive. The patient was treated with the immunosuppressant azathioprine, which resulted in clinical improvement. The patient was started on a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor evolucumab for hypercholesterolemia, which resulted in significant improvement in his lipid panel.

CONCLUSION

The case illustrates the presentation and management of statin-induced NAM. We demonstrate the necessity for prompt diagnosis and timely management, as statin therapy is contraindicated and immunosuppressive therapy is warranted. Statin-induced NAM is rare however, it should be included in the differential diagnosis of persistent myopathy despite statin discontinuation. PCSK9 inhibitors are the only alternative therapy for hypercholesterolemia management in patients with statin-induced NAM.

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.

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.

A Case of Atorvastatin-Associated Necrotizing Autoimmune Myopathy, Mimicking Idiopathic Polymyositis

Statin-induced necrotizing autoimmune myopathy (SINAM) is a rare side effect of statin use which manifests as progressive muscle weakness. Because statins are a widely prescribed medication for coronary artery disease, hyperlipidemia, and many other diseases, many patients are at risk of developing SINAM or one of the many other statin-induced myopathies. Due to identification of an antibody specific to this disease, we were able to diagnose SINAM in a patient whose symptoms had progressed to the extent that they were debilitating. Our case describes SINAM in a patient undergoing treatment with a statin for an extended period of time, diagnosis of the disease process, treatment, and resolution of symptoms.

Statin-Associated Autoimmune Myopathy: A Systematic Review of 100 Cases

BACKGROUND

Statins are a group of drugs that reduce the levels of triglycerides and cholesterol in blood by inhibiting HMG-CoA reductase, an enzyme involved in rate limiting step in cholesterol synthesis. About 2-20% patients on statins develop toxic myopathies, which usually resolve on discontinuation of statin. More recently, an immune-mediated necrotizing myopathy has been found to be associated with statin use which in most cases requires treatment with immunosuppressants.

OBJECTIVE

To perform a systematic review on published case reports and case series of statin-associated autoimmune myopathy.

METHODS

A comprehensive search of PUBMED, EMBASE, Cochrane library and ClinicalTrials.gov databases was performed for relevant articles from inception until March 19, 2016 to identify cases of statin-associated necrotizing myopathy and characterize their symptoms, evaluation and response to treatment.

RESULTS

A total of 16 articles describing 100 patients with statin-associated autoimmune myopathy were identified. The mean age of presentation was 64.72 years, and 54.44% were males. The main presenting clinical feature was proximal muscle weakness, which was symmetric in 83.33% of patients. The mean creatine kinase (CK) was 6853 IU/l. Anti-HMG-CoA reductase antibody was positive in all cases tested (n = 57/57, 100%). In patients with no anti-HMG-CoA antibody results, diagnosis was established by findings of necrotizing myopathy on biopsy. Among the 83 cases where muscle biopsy information was available, 81.48% had necrosis, while 18.51% had combination of necrosis and inflammation. Most (83.82%) patients received two or more immunosuppressants to induce remission. Ninety-one percent had resolution of symptoms after treatment.

CONCLUSION

Statin-associated necrotizing myopathy is a symmetric proximal muscle weakness associated with extreme elevations of CK. It is common in males and can occur after months of statin use. It is associated with necrosis on muscle biopsy and the presence of anti-HMG-CoA reductase antibodies. It usually requires discontinuation and immune suppression for resolution. Rechallenge with statin is unsuccessful in most cases.