Overview
How is polymyositis characterized?
What are idiopathic inflammatory myopathies?
What is necrotizing autoimmune myopathy (NAM)?
How are polymyositis and dermatomyositis differentiated?
How are polymyositis and inclusion body myositis differentiated?
What is included in patient education about polymyositis?
What is the role of viruses in the etiology of polymyositis?
What is the role of autoimmune antibodies in the etiology of polymyositis?
What are the targets of the anti-tRNA synthetase antibodies in the pathogenesis of polymyositis?
What are the targets of the anti-Jo1 antibodies in the pathogenesis of polymyositis?
What is the role of the Jo-1 antigen in the etiology of polymyositis?
How do autoantibodies against the Jo-1 antigen affect the clinical course of polymyositis?
How do Mi-2 antibodies affect the clinical course of polymyositis?
How do Anti-SRP antibodies affect the clinical course of polymyositis?
What does the presence of anti-PM/Scl autoantibodies or Anti-Ku antibodies indicate in polymyositis?
What is the role of infection in the etiology of polymyositis?
Which drugs may induce polymyositis?
What is the incidence of polymyositis?
How does the incidence of polymyositis vary by sex?
How does the incidence of polymyositis vary by age?
What is the prognosis of polymyositis?
What are the prognostic factors for polymyositis?
What are the possible complications of polymyositis?
What is the risk for venous thromboembolism (VTE) in polymyositis?
Which malignancies are more common in patients with polymyositis?
How does polymyositis affect the risk for amyotrophic lateral sclerosis (ALS)?
What mortality rate of polymyositis?
Presentation
Why is there often a delay in the diagnosis of polymyositis?
What is focus of history for polymyositis?
What are the muscular symptoms of polymyositis?
How are fine motor movements affected in patients with polymyositis?
What is the prevalence of dysphagia and dysphonia in patients with polymyositis?
How are ocular muscles affected by polymyositis?
What is the role of family history in the evaluation of polymyositis?
What are the systemic symptoms of polymyositis?
What are the pharyngeal and esophageal symptoms of polymyositis?
What is the prevalence of interstitial lung disease in polymyositis?
What are the pulmonary symptoms of polymyositis?
What are the cardiac manifestations of polymyositis?
What are musculoskeletal symptoms of polymyositis?
Which connective-tissue diseases are associated with polymyositis?
What is the prevalence of scleroderma in polymyositis?
What are the GI symptoms of polymyositis?
What are the renal manifestations of polymyositis?
What are the cutaneous manifestations of polymyositis?
What is inclusion body myositis?
How is muscle weakness characterized in polymyositis?
Which sensory exam findings are characteristic of polymyositis?
Which muscles are typically involved in polymyositis?
How does polymyositis affect respiratory muscles?
How does polymyositis affect tendon reflexes?
Which cardiac abnormalities may be present in polymyositis?
Which physical findings indicate polymyositis associated with a connective-tissue disorder?
What are the physical findings characteristic of inclusion body myositis?
What are the possible complications of polymyositis?
DDX
Which conditions should be included in the differential diagnoses of polymyositis?
What may cause drug-induced myopathy in patients with polymyositis?
What are the differential diagnoses for Polymyositis?
Workup
Which lab studies are performed in the evaluation of polymyositis?
How is malignancy assessed in the evaluation of polymyositis?
Which studies may be clinically appropriate in the evaluation of polymyositis?
How are serum creatine kinase (CK) levels affected in polymyositis?
How is myositis activity monitored in polymyositis activity?
Which muscle enzyme levels may be elevated in polymyositis?
What is the role of antinuclear antibody assays in the evaluation of polymyositis?
What is the role of muscle imaging in the evaluation of polymyositis?
Which studies may be performed to screen for malignancy in polymyositis?
What is the role of electromyography in the workup of polymyositis?
What is the role of muscle biopsy in the workup of polymyositis?
Which histologic findings are characteristic of polymyositis?
Why are inflammatory infiltrates missed in a muscle-biopsy specimen for evaluation of polymyositis?
Which histologic findings are characteristic of inclusion body myositis?
Treatment
Why is the treatment of polymyositis empirical?
What is the first-line treatment of choice for polymyositis?
What is included in treatment monitoring for polymyositis?
How is corticosteroid myopathy differentiated from reactivation of polymyositis?
What is the role of immunosuppressants in the treatment of polymyositis?
What is the role of IV immunoglobulins (IVIGs) in the treatment of polymyositis?
What is the role of tumor necrosis factor (TNF) inhibitors in the treatment of polymyositis?
What is the role of rituximab in the treatment of polymyositis?
What is the role of tacrolimus in the treatment of polymyositis?
What is the role of mycophenolate mofetil in the treatment of polymyositis?
What is the role of ACTH gel in the treatment of polymyositis?
What is the role of dietary modifications in the treatment of polymyositis?
What is the role of exercise in the treatment of polymyositis?
What is the role of physical rehabilitation programs in the treatment of polymyositis?
Which specialist consultations are beneficial in the treatment of polymyositis?
What are the treatment options for extramuscular manifestations of polymyositis?
How is dysphagia managed in polymyositis?
What testing should be performed prior to initiation of corticosteroids for polymyositis?
What is included in inpatient monitoring during treatment of polymyositis?
How frequently should patients with stable polymyositis be seen?
What is included in long-term monitoring of polymyositis?
How can complications of polymyositis be prevented?
Medications
What is the role of medications in the treatment of polymyositis?
Which medications in the drug class Immunosuppressants are used in the treatment of Polymyositis?
Which medications in the drug class Corticosteroids are used in the treatment of Polymyositis?
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Polymyositis. MRI of thighs showing increased signal in the quadriceps muscles bilaterally consistent with inflammatory myositis.
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Polymyositis. Histopathology slide shows endomysial mononuclear inflammatory infiltrate and muscle fiber necrosis.
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Polymyositis. Close view of muscle biopsy, showing chronic inflammatory infiltrate consisting of T lymphocytes, especially CD8+ T lymphocytes.
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Polymyositis. Hematoxylin and eosin frozen section shows polymyositis. Endomysial chronic inflammation is present among intact myofibers, which are remarkable only for increased variability of fiber size. Image courtesy of Roberta J. Seidman, MD.
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Polymyositis. Hematoxylin and eosin paraffin section shows polymyositis. Patient had dense endomysial inflammation that contains an abundance of plasma cells, which can be observed in patients with chronic polymyositis. Two necrotic myofibers, characterized by dense eosinophilic staining, are observed. Focal fatty infiltration of the muscle is present in the lower left quadrant of the photomicrograph. Image courtesy of Roberta J. Seidman, MD.
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Polymyositis. Hematoxylin and eosin paraffin section shows polymyositis. Photomicrograph illustrates attack on a nonnecrotic myofiber by autoaggressive T lymphocytes. On the left, the central myofiber is intact. On the right, it is obliterated by a segmental inflammatory attack. If immunohistochemistry were performed, expected findings would include an admixture of CD8 T lymphocytes and macrophages in the inflammatory process. Image courtesy of Roberta J. Seidman, MD.
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Polymyositis. Hematoxylin and eosin paraffin shows dermatomyositis. In dermatomyositis, inflammation is characteristically perivascular and perimysial. Vessel oriented approximately vertically in the center has a mild perivascular chronic inflammatory infiltrate. The endothelium is plump. The wall is not necrotic. A few lymphocytes in the wall of the vessel are probably in transit from the lumen to the external aspect of the vessel. Some observers may interpret this finding as vasculitis, but it is certainly neither necrotizing vasculitis nor arteritis. Image courtesy of Roberta J. Seidman, MD.
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Polymyositis. Hematoxylin and eosin paraffin section shows polymyositis. Longitudinal section shows a dense, chronic, endomysial inflammatory infiltrate. Image courtesy of Roberta J. Seidman, MD.