Polymyositis (PM) is an autoimmune inflammatory myopathy Myopathy Dermatomyositis caused by T cell-mediated muscle injury. The etiology of PM is unclear, but there are several genetic and environmental associations. Polymyositis is most common in middle-aged women and rarely affects children. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with progressive and symmetric proximal muscle weakness Proximal Muscle Weakness Lambert-Eaton Myasthenic Syndrome and constitutional symptoms Constitutional Symptoms Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis. Complications may arise from respiratory, cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR), or GI involvement. Diagnosis is based on clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor and laboratory studies and confirmed using muscle biopsy Muscle Biopsy Trichinella/Trichinellosis. Management is with systemic glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids, immunosuppressants Immunosuppressants Immunosuppressants are a class of drugs widely used in the management of autoimmune conditions and organ transplant rejection. The general effect is dampening of the immune response. Immunosuppressants, and physiotherapy Physiotherapy Spinal Stenosis. All patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should undergo cancer screening Screening Preoperative Care because there is a strong association with malignancy Malignancy Hemothorax.
Last updated: 29 Apr, 2022
Polymyositis (PM) is an autoimmune inflammatory myopathy Myopathy Dermatomyositis that presents as symmetric proximal muscle weakness Proximal Muscle Weakness Lambert-Eaton Myasthenic Syndrome. Antisynthetase syndrome Antisynthetase Syndrome Dermatomyositis is a subtype that shows the presence of antisynthetase antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions and certain extramuscular manifestations.
The exact etiology is unknown.
Possible genetic predisposition:
Environmental factors:
Associated medical conditions:
“Dropped head” in polymyositis: caused by weakness in the extensor muscles of the neck Muscles of the Neck The muscles of the neck can be divided into 3 groups: anterior, lateral, and posterior neck muscles. Each of the groups is subdivided according to function and the precise location of the muscles. Muscles of the Neck: Anatomy
Image by Lecturio.“Mechanic’s hands” associated with antisynthetase antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions in polymyositis: hyperkeratosis Hyperkeratosis Ichthyosis Vulgaris resulting in fissures, roughness, and scaling on the pad of the thumb and the lateral aspect of the index finger
Image: “Patient 3” by Department of Respiratory Medicine, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka City, Tokyo 181-8611, Japan. License: CC BY 2.0Histological findings in polymyositis:
Muscle biopsy
Muscle Biopsy
Trichinella/Trichinellosis from a patient with polymyositis showing endomysial inflammatory cells (arrows) and variations in fiber size
Electromyography Electromyography Recording of the changes in electric potential of muscle by means of surface or needle electrodes. Becker Muscular Dystrophy findings in polymyositis: comparison chart showing the differences in EMG activity for different pathologies
Image by Lecturio.A multidisciplinary approach including pharmacological and non-pharmacological therapies is used in the management of PM.