A case report of autoimmune necrotizing myositis presenting as dysphagia and neck swelling
© Ngo et al. 2016
Received: 23 January 2016
Accepted: 10 May 2016
Published: 17 May 2016
Severe dysphagia may occur in the immune mediated necrotizing myopathies (IMNM). Neck swelling and severe dysphagia as the initial symptoms upon presentation has not been previously described.
A 55-year-old male with a 4 week history of neck swelling, fatigue, dysphagia, myalgias, night sweats, and cough was admitted for an elevated CK. He underwent extensive infectious and inflammatory evaluation including neck imaging and muscle biopsy.
Neck CT and MRI showed inflammation throughout his strap muscles, retropharyngeal soft tissues and deltoids. Infectious work up was negative. Deltoid muscle biopsy demonstrated evidence of IMNM. Lab tests revealed anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies confirming the diagnosis of HMGCR IMNM.
HMGCR IMNM is a rare and incompletely understood disease process. Awareness of HMGCR IMNM could potentially lead to earlier diagnosis, treatment and improved clinical outcomes as disease progression can be rapid and severe.
KeywordsHMGCR Necrotizing myositis Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase Inflammatory myositis Dysphagia
The idiopathic inflammatory myopathies consist of rare autoimmune disorders that affect muscle as well as lung, skin, joints and other organ systems. They are characterized by marked symmetrical proximal muscle weakness. There is frequent CK elevation and electromyogram demonstrates a myopathy. While they often share clinical features, they can also have unique muscle biopsy findings. More recently it has been shown that approximately 60 % of patients with autoimmune myopathy have a myositis-specific autoantibody, each of which is associated with a distinct clinical phenotype. Thus future classification of these myopathies will include antibody patterns .
Immune mediated necrotizing myopathy (IMNM) has been recognized as a specific autoimmune myopathy that accounts for 19 % of all inflammatory myopathies . In contrast to the idiopathic inflammatory myopathies which are characterized histopathologically by an inflammatory exudate, IMNM muscle biopsies show prominent fiber necrosis with minimal or no inflammation. Much attention has recently focused on IMNM associated with autoantibodies that recognize 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), the pharmacological target of statins . HMGCR IMNM presents with symmetric proximal arm and leg weakness, myalgias, dysphagia and arthralgias . While dysphagia occurs in about 20–35 % of patients [3, 5], prominent head and neck symptoms as the presenting complaint have not been described.
HMGCR IMNM has an aggressive and debilitating clinical course characterized by significant muscle necrosis. It is highly associated with current statin use, prior statin exposure and also can be idiopathic in a small number of cases but differs from statin induced myopathy [6–8]. Statin induced myopathy, is commonly characterized by myalgias with statin use that stop with discontinuation of the offending agent, and is a separate non-autoimmune entity . On the other hand, HMGCR IMNM is an autoimmune disease that requires specific therapy and possibly long-term immunosuppression. HMGCR IMNM is associated with dysphagia in up to 35 % of patients, symmetric proximal muscle weakness in 95 %, distal muscle weakness in 41 %, and dyspnea in 37 %. CKs over 6000 and significant necrosis on muscle biopsy are commonly seen [6–8].
In 2011, a novel antibody to HMGCR was discovered in 6 % of a cohort of autoimmune inflammatory myositis patients (n = 750) at Johns Hopkins University School of Medicine . Two-thirds of the patients had prior statin exposure. All patients with anti-HMGCR antibody IMNM demonstrated prominent necrosis with varying levels of inflammation on pathology. Statin-naïve patients were younger but the two subgroups were indistinguishable on pathology. Subsequent research supports the theory that this process is both due to genetic and environmental factors. Patients with HLA class II allele DRB1*11:01 have been shown to have an increased risk of developing HMGCR IMNM . One possible model has been proposed by Mammen et al. HMGCR is an enzyme target of statins and has been shown to be upregulated in skeletal muscle cells that are exposed to statins in vivo . Increased expression of the HMGCR triggers an immune response with formation of HMGCR antibodies and resultant skeletal muscle destruction and regeneration. In addition, regenerating muscle cells have also been demonstrated to increase expression of HMGCR  thereby potentiating the process over an extended period of time even after statin exposure is removed.
Treatment of anti-HMGCR IMNM requires several agents. Prednisone monotherapy is inadequate in up to 90 % of patients and most patients required 2 or more immunosuppressives . Relapse rate is approximately 50–55 % in patients that taper off therapy [3, 6]. IVIG within the first three months of presentation has potentially promising outcomes with patients achieving significant improvement at 6 months [3, 13].
A 55 year old African American male was admitted to the hospital with a 4 week history of difficulty swallowing, hoarseness, fatigue, neck swelling, night sweats and a 20 lb weight loss. He had no muscle weakness. He had type II diabetes mellitus and hyperlipidemia. His medications included atorvastain 40 mg daily which he was taking for 2 years. There was no history of rhabdomyolysis, or autoimmune disease.
On exam, he was afebrile with normal oxygen saturation on room air. His voice was notably hoarse and he had difficulty clearing his secretions. His neck was swollen symmetrically, non-tender, and without lymphadenopathy. Cardiovascular, pulmonary and gastrointestinal examination was unremarkable. Strength was 5/5 throughout, and he was able to stand and walk independently. There were no vasculitic skin lesions.
Pertinent lab values across management course
Day # of Management
Creatine Kinase (CK) (0–170 U/L)
Anti-HMGCR Antibody (<20 U)
Creatinine (0.66–1.25 mg/dL)
Erythrocyte Sedimentation Rate (ESR) (0–15 mm/h)
C-Reactive Protein (CRP) (0.0–0.9 mg/dL)
Hemoglobin (13.5–17.5 g/dL)
Platelets (150–450 k/uL)
White Blood Count (4.0–11.0 k/uL)
Aspartate transaminase (AST) (0–66 U/L)
Alanine transaminase (ALT) (0–69 U/L)
Alkaline Phosphatase (38–126 U/L)
Bilirubin, Direct (0.0–.3 mg/dL)
Bilirubin, Total (0.2–1.3 mg/dL)
He rapidly developed respiratory weakness with negative inspiratory force and vital capacity of -55 cm H2O (expected >80 cm H20) and 3.72 L (expected >3.8 L) respectively. This was followed by rapid and severe weakness of proximal upper and lower extremity muscles with inability to abduct his arms and stand up from seated position without assistance. He required a feeding tube for nutrition.
Treatment was initiated with IV methylprednisolone 500 mg daily for 3 days, which was followed by 5 days of plasmapheresis, followed by intravenous immunoglobulin (IVIG) therapy with 1 g/kg daily for 2 days.
Subsequently, the patient was transferred to inpatient rehabilitation where he had progressive improvement in general fatigue, strength, and swallowing. He was discharged home requiring minimal assistance and after 3 months resumed all his usual activities. He was subsequently placed on methotrexate 15 mg weekly and a prednisone was tapered over the next 4 months without further complications.
Prior to this report, no severe head and neck involvement has been described as the initial presentation of IMNM that closely resembled severe infection. Otolaryngologists may be consulted for head/neck involvement and severe dysphagia and should be aware of HMGCR antibody associated IMNM. Early recognition will allow for prompt initiation of immunosuppressive therapy and likely lead to better clinical outcomes.
Consent for publication
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.
Availability of data and materials
3-hydroxy-3-methylglutaryl-coenzyme A reductase
immune mediated necrotizing myopathies
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- Mammen AL. Autoimmune myopathies: autoantibodies, phenotypes and pathogenesis. Nat Rev Neurol. 2011;7:343–54.View ArticlePubMedGoogle Scholar
- van der Meulen MF, Bronner IM, Hoogendijk JE, et al. Polymyositis: an overdiagnosed entity. Neurology. 2003;61:316–21.View ArticlePubMedGoogle Scholar
- Kassardjian CD et al. Clinical features and treatment outcomes of necrotizing autoimmune myopathy. JAMA Neurol. 2015;72:996–1003.View ArticlePubMedGoogle Scholar
- Albyayda J, Christopher-Stine L. Identifying statin-associated autoimmune necrotizing myopathy. Clev Clin J Med. 2014;81:736–41.View ArticleGoogle Scholar
- Mohassel P, Mammen AL. Statin-associated autoimmune myopathy and anti-HMGCR autoantibodies. Muscle Nerve. 2013;48:477–83.View ArticlePubMedGoogle Scholar
- Grable-Esposito P et al. Immune-mediated necrotizing myopathy associated with statins. Muscle Nerve. 2010;41:185–90.PubMedGoogle Scholar
- Babu S, Li Y. Statin induced necrotizing autoimmune myopathy. J Neurol Sci. 2015;351:13–7.View ArticlePubMedGoogle Scholar
- Needham M et al. Progressive myopathy with up-regulation of MHC-I associated with statin therapy. Neuromuscul Disord. 2007;17:194–200.View ArticlePubMedGoogle Scholar
- Joy TR, Hegele RA. Narrative review: statin-related myopathy. Ann Intern Med. 2009;150:858–68.View ArticlePubMedGoogle Scholar
- Mammen AL et al. Autoantibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase in patients with statin-associated autoimmune myopathy. Arthritis Rheum. 2011;63:713–21.View ArticlePubMedPubMed CentralGoogle Scholar
- Mammen AL et al. Increased frequency of DRB1* 11: 01 in anti–hydroxymethylglutaryl-coenzyme A reductase–associated autoimmune myopathy. Arthritis Care Res. 2012;64:1233–7.View ArticleGoogle Scholar
- Morikawa S et al. Analysis of the global RNA expression profiles of skeletal muscle cells treated with statins. J Atheroscler Thromb. 2005;12:121–31.View ArticlePubMedGoogle Scholar
- Mammen AL, Tiniakou E. Intravenous immune globulin for statin-triggered autoimmune myopathy. New N Engl J Med. 2015;373:1680–2.View ArticleGoogle Scholar