Materiały źródłowe

• #1 Diagnosis – Polymyositis (PM) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/polymyositis/diagnosis

  People with polymyositis (PM) may exhibit some characteristic signs and symptoms, such as chronic muscle weakness. Given that PM presents similarly to other idiopathic inflammatory myopathies (IIMs), however, diagnosis of PM is often achieved by exclusion of other IIM subgroups. Diagnosis may require a combination of testing modalities. […] New research and a better understanding of the IIMs has improved the ability to distinguish between and diagnose the different IIM subgroups. Many cases that were previously diagnosed as PM are now thought to be better classified as one of the other IIMs based on the above testing criteria.

• #1 Polymyositis – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/polymyositis/diagnosis-treatment/drc-20353212

  If your doctor suspects you have polymyositis, he or she might suggest some of the following tests: […] A blood test will let your doctor know if you have elevated levels of muscle enzymes, which can indicate muscle damage. A blood test can also detect specific autoantibodies associated with different symptoms of polymyositis, which can help in determining the best medication and treatment. […] This test involves inserting a thin needle electrode through the skin into the muscle. Electrical activity is measured as you relax or tighten the muscle, and changes in the pattern of electrical activity can confirm a muscle disease. The doctor can determine the distribution of the disease by testing different muscles. […] A scanner creates cross-sectional images of your muscles from data generated by a powerful magnetic field and radio waves. Unlike a muscle biopsy, an MRI can assess inflammation over a large area of muscle.

• #1 Polymyositis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/335925-overview

  Polymyositis is an idiopathic inflammatory myopathy characterized by the following: Progressive symmetric, predominantly proximal muscle weakness. Elevated skeletal muscle enzyme levels. Characteristic electromyography (EMG) and muscle biopsy findings. […] Treatment of polymyositis is empirical because of the rarity of the disease and the paucity of randomized controlled trials. Prednisone is the first-line treatment of choice. Immunosuppressive agents are indicated in patients who do not improve within a reasonable period (ie, 4 wk) or in whom adverse effects from corticosteroids develop. Limited data support the use of other agents. […] The pathogenesis of polymyositis appears to be a T-cell-mediated cytotoxic process directed against unidentified muscle antigens. Supporting this conclusion is the involvement of CD8 T cells, which, along with macrophages, initially surround healthy nonnecrotic muscle fibers and eventually invade and destroy them.

• #1 Understanding Polymyositis and Its Effect on Your Body

  https://www.healthline.com/health/polymyositis

  A doctor will need to officially diagnose polymyositis. This visit could involve: […] using blood tests to look for and identify certain autoantibodies […] having a muscle biopsy can help determine whether your muscles are swollen, infected, or physically altered. […] These various tools can help the doctor make an accurate assessment of your condition and start you on the right treatment plan. […] Your doctor can diagnose the condition with a range of tests and help determine a treatment plan that works for your needs.

• #1 Polymyositis – Myositis Support and Understanding

  https://understandingmyositis.org/myositis/polymyositis/

  Polymyositis is diagnosed and managed by either a rheumatologist or neurologist, with a neuromuscular specialist likely having the most experience, usually in coordination with a primary care physician (PCP). Consultation with other specialists may be required depending on your symptoms, other coexisting illnesses, and other organ involvement and may include a cardiologist, pulmonologist, oncologist, and pain management specialist. […] A complete medical and family history are important in helping to diagnosis a rare and complex disease such as polymyositis. We suggest writing a detailed medical and family history that you can share with your medical team and that can be used for all future appointments. […] Your doctor will likely order various blood tests when suspecting polymyositis in order to measure autoimmune and inflammatory markers and to check for myositis-specific and myositis-associated antibodies, cancer markers (if suspected) and other antibodies.

• #1 Polymyositis – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/polymyositis/diagnosis-treatment/drc-20353212

  During this test, a small piece of muscle tissue is surgically removed for laboratory analysis. Analysis may reveal abnormalities, such as inflammation, damage, certain proteins or enzyme deficiencies. […] When you go in to see your doctor, be sure to have a record of your symptoms. Although it may be difficult to pinpoint when symptoms started, try to estimate when you first noticed weakness, and which muscles have been affected. You may want to write a list that includes: […] What kind of tests might I need? Are any special preparations required? […] Your doctor will likely ask you several questions, such as: […] What other symptoms are you experiencing? […] Are you currently taking any medications or dietary supplements?

• #1 Myositis: Muscle Inflammation | Inflammatory Myopathy | HSS

  https://www.hss.edu/condition-list_myositis.asp

  How is myositis diagnosed? […] Myositis can be hard to diagnose, but comprehensive assessment using all the tools available can make this possible. A diagnosis is made by taking the patients history, conducting a physical exam, and performing diagnostic tests, including. These may include blood tests, imaging exams (MRI and/or ultrasound), electromyography and nerve conduction studies, and biopsies of the muscle and/or skin. […] Patients with myositis usually complain of muscle weakness, particularly in the proximal muscle groups like the deltoids in the arms and the quadriceps in the upper legs. A doctor can often detect and quantify the degree of muscle weakness with a simple physical exam. […] Diagnostic blood tests will usually show high levels of muscle enzymes in the circulation, which is a sign of muscle breakdown and damage.

• #1 Diagnosing Inflammatory Myopathies | NYU Langone Health

  https://nyulangone.org/conditions/inflammatory-myopathies/diagnosis

  A correct diagnosis is vital to managing pain and muscle weakness associated with inflammatory myopathies. […] To diagnose an inflammatory myopathy, an NYU Langone doctor takes a thorough medical history, performs a physical exam, and tests your muscle strength. […] Doctors use a blood test to look for elevated levels of a substance called creatine kinase, which is released into the bloodstream when muscle fibers deteriorate. Elevated levels may mean you have an inflammatory myopathy. […] A blood test alone doesn’t provide a definitive diagnosis, and additional tests are necessary. Doctors may also send blood to be tested for antibodies that are associated with polymyositis. […] In this outpatient procedure, a doctor numbs the area to be tested with a local anesthetic and surgically removes a small piece of muscle. This is examined under a microscope for signs of chronic inflammation or muscle fiber death, which may signal an inflammatory disease.

• #1 Polymyositis Workup: Approach Considerations, Imaging Studies, Electromyography

  https://emedicine.medscape.com/article/335925-workup

  The following laboratory findings may be present in polymyositis: […] Complete blood count (CBC) – May show leukocytosis or thrombocytosis; leukocytosis is present in more than 50% of patients […] Erythrocyte sedimentation rate or C-reactive protein level – Elevated in 50% of patients with polymyositis […] Elevated muscle enzyme levels […] Myoglobinuria […] Autoantibodies […] Positive rheumatoid factor – Found in more than 50% of patients. […] Serum creatine kinase (CK) levels are usually elevated in persons with polymyositis, ranging from 5-50 times the reference range. […] Serum CK levels, along with careful physical examination, may be used to monitor myositis activity. […] Antinuclear antibody assays are positive in one third of patients with polymyositis and in only 15% of patients with inclusion body myositis.

• #1 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Test availability […] Quest Diagnostics offers tests and panels that may be useful for classifying or diagnosing myositis. […] Table 1. Laboratory Tests for Classification and Diagnosis of Myositis […] Alanine Aminotransferase (ALT) – Diagnose PM/DM […] Aldolase – Diagnose PM/DM […] Anti-PM/Scl-100 Antibody, EIA – Diagnose overlap of PM/DM with systemic sclerosis […] Aspartate Aminotransferase (AST) – Diagnose PM/DM […] Creatine Kinase (CK), Total – Diagnose PM/DM […] Cytosolic 5’-Nucleotidase 1A (cN-1A) Antibody (IgG) – Diagnose sporadic inclusion body myositis […] Extended Myositis Specific Antibody (MSA) Panel – Diagnose PM/DM (Jo-1 provides a more definitive diagnosis) Diagnose IMNM Diagnose cancer-associated DM Diagnose juvenile DM Diagnose amyopathic DM Diagnose statin-induced myopathy Diagnose sporadic inclusion body myositis

• #1 Polymyositis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/335925-overview

  An autoimmune response to nuclear and cytoplasmic autoantigens is detected in about 60-80% of patients with polymyositis and dermatomyositis. Some serum autoantibodies are shared with other autoimmune diseases, and some are unique to myositis. […] The presence of autoantibodies against the Jo-1 antigen has been reported in 15-30% of polymyositis patients by immunodiffusion. Anti-Jo-1 antibodies are almost completely specific for myositis and are more common in polymyositis than in dermatomyositis. […] Polymyositis is an immune-mediated syndrome secondary to defective cellular immunity that is most commonly associated with other systemic autoimmune diseases. […] Polymyositis usually affects adults older than 20 years, especially those aged 45-60 years. Polymyositis rarely affects children.

• #1 Polymyositis / Dermatomyositis Diagnosis and Treatment – Autoimmune Disorders for Medicine

  https://www.picmonic.com/pathways/medicine/courses/standard/pathology-196/autoimmune-disorders-39340/polymyositis-dermatomyositis-diagnosis-and-treatment_2640

  Polymyositis (PM) and dermatomyositis (DM) are two separate but closely related diseases that are classified as idiopathic inflammatory myopathies. Diagnostic labs include increased creatine kinase (CK), increased aldolase, presence of anti-Jo-1 antibodies, antinuclear (ANA) antibodies, and anti-SRP antibodies, abnormal electromyography (EMG), and muscle biopsy findings. […] An elevated serum level of muscle enzymes like creatine kinase (CK) and aldolase are characteristic but not specific to dermatomyositis and polymyositis. However, they are useful initial tests when the diagnoses are suspected. […] Myositis-specific antibodies like anti-Jo-1 antibody and anti-SRP (signal recognition particle) antibody can be detected in both these diseases. Anti-Jo-1 antibody is a type of antisynthetase antibody, a class of antibody that is related to an overarching condition called antisynthetase syndrome, that some patients with DM or PM may fall under.

• #1 Inflammatory Myopathies Difficult to Diagnose, Treat – The Rheumatologist

  https://www.the-rheumatologist.org/article/inflammatory-myopathies-difficult-to-diagnose-treat/

  Because there is no gold standard for diagnosing idiopathic inflammatory myopathies, we are forced to rely on criteria. […] For the diagnosis of polymyositis, they proposed the combination of proximal muscle weakness, elevated serum levels of enzymes derived from skeletal muscle, a classic triad of electromyographic (EMG) abnormalities, and the presence of inflammation on muscle biopsy. […] When elevated, the enzyme most considered to be a sign of myositis is creatine phosphokinase (CPK). […] Some patients have normal CPK levels throughout their course. […] The classic triad of EMG changes described includes: 1) fibrillation at rest, increased insertional activity, and spontaneous and positive sharp waves; 2) bizarre high-frequency repetitive discharges; and 3) polyphasic potentials of short duration and low amplitude. […] However, this triad is not diagnostic and is generally present in only 40% of patients with myositis, while 10% of patients with these diseases have normal EMG results.

• #1 Polymyositis – Myositis Support and Understanding

  https://understandingmyositis.org/myositis/polymyositis/

  An EMG (Electromyography) is a test that checks the health of the muscles and the nerves that control the muscles. With polymyositis, the EMG may show myopathic changes. EMG testing can help distinguish between weakness due to muscle disease from weakness due to nerve problems. Nerve conduction study is usually done during the same visit and is a test to see how fast electrical signals move through a nerve. […] MRI is being used more frequently for polymyositis and can show changes suggesting muscle inflammation. Physicians may also use MRI to choose the best muscle for biopsy. […] The muscle biopsy has long been considered a gold standard for a diagnosis of polymyositis. A doctor will remove a small piece of muscle tissue, either via a needle biopsy or an open surgical biopsy, and send it to a lab for testing.

• #1 Polymyositis | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/polymyositis?lang=us

  Polymyositis is an increasingly rare diagnosis. […] MRI has been used for diagnosis, follow-up, and to identify the best site for muscle biopsy. […] Management is with immunosuppression, similar to dermatomyositis. […] On MRI there is a broad differential: differential diagnosis of skeletal muscle edema on MRI.

• #1 Polymyositis – Types, Causes, Symptoms, Complications, Diagnosis, Treatment

  https://www.medindia.net/health/conditions/polymyositis.htm

  Polymyositis is diagnosed based on: […] Blood tests show elevated erythrocyte sedimentation rate (ESR), C-reactive protein and increased white blood cells (leukocytosis), which are all indicative of inflammation. The levels of the enzymes creatine kinase and aldolase are increased, which indicate muscle damage. […] Muscle biopsy shows findings consistent with death and degeneration of muscle tissue and inflammation. […] Electromyography is the testing of muscles electrical activity and shows signs of muscle damage in polymyositis. […] Antibody test: Anti-Jo-1 antibodies are detected in the blood in 20% of cases. […] Urine analysis: Myoglobinuria, i.e. excretion of the protein myoglobin derived from muscles in the urine, is present. […] CT scan is used to detect any associated cancers, which could cause polymyositis. […] Magnetic Resonance Imaging (MRI) is used to evaluate the extent of muscle involvement.

• #1 Polymyositis and Dermatomyositis – Brigham and Women’s Hospital

  https://www.brighamandwomens.org/medicine/rheumatology-inflammation-immunity/services/polymyositis-and-dermatomyositis

  Diagnosis of the inflammatory muscle disease is usually done with a combination of physical examination and lab tests that measure muscle inflammation. […] Other tests that may be needed include: […] Biopsy of the affected muscle to show inflammation. […] MRI, which can show inflammation in the muscle. […] Electromyography (EMG), which can show which muscles are involved. […] Especially when EMG or muscle biopsy is being considered, rheumatologists will consult with a neurologist to determine the best diagnostic plan to guide treatment. […] If there is a suspicion of inflammation of the lung, specific breathing tests that measure lung function (pulmonary function tests) and sometimes a CT scan of the chest may be needed.

• #1 Polymyositis – adult: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000428.htm

  Polymyositis and dermatomyositis are rare inflammatory diseases. (The condition is called dermatomyositis when it involves the skin.) These diseases lead to muscle weakness, swelling, tenderness, and tissue damage. They are part of a larger group of diseases called myopathies, more specifically inflammatory myopathies. […] Polymyositis affects the skeletal muscles. It is also known as idiopathic inflammatory myopathy. The exact cause is unknown, but it may be related to an autoimmune reaction or infection. […] Tests may include: […] Autoimmune antibodies and inflammation tests […] Serum CPK (creatine phosphokinase) […] Serum aldolase […] Electromyography […] MRI of affected muscles […] Muscle biopsy […] Myoglobin in the urine […] ECG […] Chest x-ray and CT scan of the chest […] Pulmonary function tests […] Esophageal swallowing study […] Myositis specific and associated autoantibodies. […] A repeat muscle biopsy may be needed to make this diagnosis.

• #1 Myositis: Muscle Inflammation | Inflammatory Myopathy | HSS

  https://www.hss.edu/condition-list_myositis.asp

  A muscle biopsy is the gold standard to diagnosis myositis. It can demonstrate inflammatory changes in the muscle tissue that is, cellular- and molecular-level evidence of muscle damage caused by the immune system. […] How is a diagnosis of polymyositis versus dermatomyositis made? […] A muscle biopsy is a common method to diagnose the condition. In people with dermatomyositis, there may be more skin involvement, such as a rash, and a skin biopsy can be done. Blood tests, magnetic resonance imaging (MRI), and other specialized neurologic tests, such as EMG testing, can be helpful as well.

• #1 Polymyositis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK563129/

  Polymyositis, a relatively uncommon autoimmune disorder, develops due to abnormal activation of cytotoxic T lymphocytes (CD8 cells) and macrophages against muscular antigens that result in rhabdomyolysis and ultimately presents as a proximal myopathy. […] Describe the appropriate evaluation process for polymyositis. […] Polymyositis develops over the months as compared to inclusion body myositis (IBM), which is a slowly progressive chronic myopathy developing in older individuals over a period of months to years with more severe symptoms. […] Polymyositis (PM), an autoimmune disorder, develops due to abnormal activation of cytotoxic T lymphocytes (CD8 cells) and macrophages against muscular antigens as well as the strong extrafusal muscular expression of major histocompatibility complex 1, causing damage to the endomysium of skeletal muscles.

• #1 Polymyositis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK563129/

  The multi-modal approach of hematologic and serologic testing, imaging, electromyography, nerve conduction studies, and biopsy findings is used to evaluate a patient with suspected polymyositis. […] Almost all the patients with PM will have abnormal electromyography (EMG) findings, such as varying amplitude and velocity of the membranous action potential and fibrillation in potentials due to membrane irritability. A vital investigation to make a definitive diagnosis of myopathy is a magnetic resonance imaging, or EMG-guided biopsy that shows perivascular and endomysial mononuclear infiltrates (cytotoxic T lymphocytes and macrophages) and areas of necrosis staining pink due to high eosin stain binding. […] Polymyositis is treated with a combination of different pharmacological and non-pharmacological modalities. Pharmacological treatment mainly includes corticosteroids. Prednisone and methylprednisolone are the most common corticosteroids used for polymyositis, with a starting dose of 1 mg/kg of prednisone a day.

• #1 Diagnosis and management of inflammatory muscle disease

  https://www.hcplive.com/view/diagnosis-and-management-inflammatory-muscle-disease

  Muscle histology can help identify the specific type of idiopathic inflammatory myopathy; however, histological changes may be minimal or nonspecific. […] In polymyositis, muscle fibers are seen in various stages of necrosis and regeneration. […] The classic findings of muscle inflammation are seen in polymyositis, dermatomyositis, and inclusion body myositis. […] The histopathology of inclusion body myositis may be identical to that seen in polymyositis. […] Dermatomyositis has a higher association with malignancies than polymyositis or inclusion body myositis. […] A CT scan of the chest, abdomen, and pelvis and a thorough screening for age-appropriate cancer are recommended at the time of diagnosis.

• #1 Polymyositis | Baylor Medicine

  https://www.bcm.edu/healthcare/specialties/neurology/neuromuscular-diseases/conditions/polymyositis

  The first step in the diagnosis of polymyositis is obtaining a history and physical examination compatible with the picture usually seen in this entity. […] An electromyogram is then performed which usually shows findings of muscle irritability in association with characteristic myopathic units. […] The next step in the diagnosis is the performance of a muscle biopsy. A muscle biopsy is necessary to differentiate between polymyositis and other inflammatory myopathies and to also rule out any other muscle condition that could be mimicking polymyositis. […] When the diagnosis of polymyositis is confirmed, treatment can be initiated.

• #1 Polymyositis

  https://mobile.fpnotebook.com/Rheum/Diffuse/Plymysts.htm

  Polymyositis Diagnosis (4 or more criteria below) Proximal Muscle Weakness (trunk, thighs, Shoulders) Increased serum Creatine Phosphokinase or Aldolase Muscle pain on grasping or spontaneously EMG myogenic changes (see Polymyositis Evaluation) Positive anti-Jo1 Antibody Nondestructive Arthritis or Arthralgia Pathologic inflammatory signs Systemic inflammation signs Temperature over 37 C at axilla C-Reactive Protein increased Erythrocyte Sedimentation Rate 20 mm/hour […] Four or more findings seen in Polymyositis (below)

• #1 Diagnostic criteria for Polymyositis – The Myositis Association

  https://www.myositis.org/about-myositis/diagnosis/diagnostic-criteria/diagnostic-criteria-for-polymyositis/

  A diagnosis of polymyositis should be considered for patients presenting with no skin symptoms and four of the following criteria: […] Muscle biopsy findings compatible with inflammatory myositis: […] Diagnostic criteria.

• #1

  https://empendium.com/mcmtextbook/table/B31.16.7-1.

  1. Symmetric progressive muscle weakness affecting the muscles of the shoulder and hip […] 2. Histologic findings typical of myositis (see text) […] 3. Increased plasma creatine kinase levels […] 4. Electromyographic features of an irritative myopathy (active changes and myopathic potentials) […] 5. Typical cutaneous manifestations: Gottron sign, heliotrope rash, or rash on the anterior chest and shoulders […] […] […] Definite […] Probable […] Possible […] […] […] Number of symptoms […] […] […] PM […] 4 […] 3 […] 2 […] […] […] DM […] 3 or 4 […] 2 […] 1 […] […] […] Plus typical cutaneous manifestations

• #1 Inflammatory Myopathies | Choose the Right Test

  https://arupconsult.com/content/inflammatory-myopathies

  Laboratory testing for inflammatory myopathies is appropriate in individuals with progressive muscle weakness, particularly in patients with muscular, cutaneous, pulmonary, and articular manifestations, after more common etiologies have been ruled out. […] The European League Against Rheumatism (EULAR) and American College of Rheumatology (ACR) published updated classification criteria for inflammatory myopathies in 2017. These criteria, presented in the following table, were intended to improve on the sensitivity and specificity of the 1975 Bohan and Peter criteria, help differentiate inflammatory myopathies from conditions with similar presentations, and distinguish the primary inflammatory myopathy subtypes. […] Identification of the particular inflammatory myopathy subtype can be performed only in cases of a diagnostic probability of 55% (corresponding to a EULAR/ACR score of 5.5 without biopsy data or 6.7 with biopsy data), per the EULAR/ACR criteria.

• #1 Polymyositis Diagnosis And Treatment – Klarity Health Library

  https://my.klarity.health/polymyositis-diagnosis-and-treatment/

  Polymyositis is a chronic autoimmune disorder in which the immune system attacks and destroys muscles close to the trunk of the body, causing myopathy (muscle disease). […] The diagnosis of polymyositis is a diagnosis of exclusion; that is, it can only be diagnosed if the diagnostic criteria for other idiopathic inflammatory myopathies are not met. […] A comprehensive evaluation is required to diagnose the entire range of myopathies, including polymyositis. […] Different classification criteria have been created to facilitate diagnosis. One that has proven useful and effective is the European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) Classification criteria. […] This EULAR/ACR allows doctors to differentiate between possible, probable and definitive cases of polymyositis.

• #1 The diagnosis and classification of polymyositis – PubMed

  https://pubmed.ncbi.nlm.nih.gov/24461380/

  Polymyositis is classified as a separate entity among idiopathic inflammatory myopathies but it is considered as the least common since it is an exclusion diagnosis. […] Although serum autoantibodies, EMG and imaging techniques can help in diagnosis, muscle histopathology is a pivotal value. […] A broad differential diagnosis is needed before concluding a diagnosis of pure PM. […] Finally, a diagnostic algorithm for suspected cases of PM is also proposed.

• #1 Diagnosis and differential diagnosis of dermatomyositis and polymyositis in adults – UpToDate

  https://www.uptodate.com/contents/diagnosis-and-differential-diagnosis-of-dermatomyositis-and-polymyositis-in-adults

  Diagnosis and differential diagnosis of dermatomyositis and polymyositis in adults […] The diagnosis and differential diagnosis of DM and „PM” in adults will be reviewed here. […] There is growing understanding that the term PM is falling out of favor given the increased understanding that many cases that would previously have been classified as PM are now better classified as the antisynthetase syndrome (without a characteristic rash), overlap myositis (with another connective tissue disease), or immune-mediated necrotizing myopathy (IMNM). […] While it is now understood that muscle biopsy features are distinct in IMNM, previous studies often labeled these cases as PM, assuming the primary inflammation had been missed on the muscle biopsy sampling.

• #1 Polymyositis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK563129/

  The presence of anti-aminoacyl tRNA synthetase antibodies can show the association of PM with an autoimmune syndrome known as anti-synthetase syndrome. This is characterized by a group of varying physical presenting features such as inflammation-induced myopathy, joint pain, Raynaud’s phenomenon, and fibrotic lung disease.

• #1 Polymyositis | Better Health Channel

  https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/polymyositis

  Polymyositis is sometimes mistaken for muscular dystrophy, so careful diagnosis is important. […] Some of the tests for polymyositis include: […] Medical history people with other connective tissue diseases, such as scleroderma, are at greater risk of polymyositis. […] Physical examination this includes general tests. […] Electromyography wires attached to the skin measure the electrical activity of muscles. […] Muscle biopsy a small tag of muscle tissue is removed and examined in a laboratory for evidence of degeneration and abnormal immune system activity. This is the definitive test for polymyositis. […] Scans these include magnetic resonance imaging. […] Blood tests an antibody titre is included, since polymyositis is characterised by the overproduction of particular antibodies. There are also higher than normal amounts of a muscle enzyme indicating muscle damage (creatine phosphokinase) circulating in the bloodstream, which can be measured by a specific blood test. […] Other tests these are used to exclude other causes such as bacterial or parasitical infections of muscle tissue.

• #1 Myositis – Polymyositis and Dermatomyositis – Patient.info

  https://patient.info/doctor/myositis-polymyositis-and-dermatomyositis

  Polymyositis produces muscle weakness. It is not painful, although a few patients complain of aches or cramps. […] The diagnosis is established by electromyography (EMG) and is confirmed by muscle biopsy. In polymyositis it is the definitive test. […] Polymyositis is a diagnosis of exclusion and other considerations include: hereditary neuromuscular diseases, endocrine disease including thyrotoxicosis and Cushing’s disease, malabsorption syndromes, alcoholism, cancer, vasculitis, granulomatous disease, sarcoidosis or exposure to drugs or toxins that affect the muscles. […] The prognosis of the idiopathic inflammatory myopathies is very variable. An associated malignancy indicates a poor prognosis for recovery and increases mortality. Overall, drug-free remissions are rare except in juvenile dermatomyositis. Studies have shown that only 20% to 40% of treated patients will achieve polymyositis or dermatomyositis remission, whereas 60% to 80% will experience a polycyclic or chronic continuous course of the disease. Mortality remains 2-3 times higher than in the general population, with cancer, lung, cardiac complications and infections being the most common causes of deaths. Poor prognostic factors include older age, male gender, non-Caucasian ethnicity, longer symptom duration, cardiac involvement, dysphagia, malignancy and serum myositis-specific antibodies (including co-existence of anti-Ro52 and anti-Jo1 antibodies, presence of antisignal recognition particle antibody, anti-155/140, and anti-CADM-140 antibodies). […] The diagnosis is established by electromyography (EMG) and is confirmed by muscle biopsy. In polymyositis it is the definitive test.

• #1 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Myositis: Laboratory Support for Classification and Diagnosis […] This Clinical Focus provides an overview of the use of laboratory testing to classify and diagnose myositis caused by the idiopathic inflammatory myopathies. […] The differential diagnosis of IIMs and overlap myositis begins with the exclusion of muscular dystrophy and myopathies of known cause (eg, infectious, metabolic, drug-induced, or neurologic). Diagnosis is aided by imaging, electromyography, biopsy, testing levels of muscle enzymes in serum, and the detection of myositis-specific and myositis-associated antibodies. In addition, the detection of certain antibodies may have prognostic value. […] Individuals suitable for testing […] Individuals with symptoms of IIM (eg, unexplained muscle weakness, rash, evidence of systemic disease)

• #1 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Jo-1 Antibody – Diagnose PM/DM […] Lactate Dehydrogenase (LD) – Diagnose PM/DM […] Myositis Specific 11 Antibody Panel – Diagnose PM/DM (Jo-1 provides a more definitive diagnosis) Diagnose IMNM Diagnose cancer-associated DM Diagnose juvenile DM Diagnose amyopathic DM […] Sjogren’s Antibody (SS-A) – Diagnose overlap of PM/DM with Sjögren syndrome, SLE, or systemic sclerosis […] Sm/RNP Antibody – Diagnose overlap of PM with SLE or systemic sclerosis […] On initial evaluation, about 80% to 90% of myositis patients have elevated creatine kinase (CK) associated with muscle damage. Using elevated CK to diagnose IIMs has limitations, however. CK levels may be only slightly elevated, or normal, due to lack of muscle mass or the presence of circulating CK inhibitors or CK antibodies. Normal CK levels may also be observed in patients with IBM, as well as those with juvenile or amyopathic dermatomyositis. Another limitation is that CK and other muscle enzymes are not specific markers of polymyositis/dermatomyositis. Serum elevations may be due to other types of muscle disease (muscular dystrophies, rhabdomyolysis), hypothyroidism, cardiac, or liver disease. Consequently, tests employing antibody markers, rather than muscle enzymes, are used to specifically diagnose and classify IIMs.

• #1 Polymyositis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/335925-overview

  In most patients, polymyositis responds well to treatment, although residual weakness occurs in approximately 30% of patients. […] Poor prognostic factors include advanced age, female sex, African-American race, interstitial lung disease, presence of anti-Jo-1 and anti-SRP antibodies, associated malignancy, delayed or inadequate treatment, dysphagia, dysphonia, and cardiac and pulmonary involvement. […] Five-year survival rates in polymyositis have been estimated at more than 80%. Mortality is most often related to associated malignancy or pulmonary complications.

• #1 Polymyositis – Myositis Support and Understanding

  https://understandingmyositis.org/myositis/polymyositis/

  Since there is an increased risk and a potential association of cancer with polymyositis, your doctor may perform several cancer screenings, including those that are age and gender appropriate. […] Diagnosing polymyositis can be a long and difficult process for several reasons. […] The diagnosis can be delayed when characteristic findings are not present such as proximal muscle weakness, elevated muscle enzymes such as creatine kinase (CK or CPK) and aldolase, myopathic findings on electromyography (EMG), and typical muscle biopsy findings for PM.

• #1 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Myositis-specific antibodies for IBM and IMNM have been more recently described: […] cN-1A antibodies target cytosolic 5’-nucleotidase and have been reported to be highly predictive for IBM with high specificity (87%-100%) but wide ranging sensitivity estimates (33%-76%). However, cN-1A antibodies may be detected in some patients with other clinical phenotypes of myositis and other autoimmune diseases, including polymyositis (≤5%), dermatomyositis (≤15%), SLE (10%-20%), and Sjögren syndrome (12%-36%). […] HMGCR antibodies target 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR); positive results correctly identify nearly 100% of patients with IMNM. However, sensitivity for IMNM is about 45%. […] Myositis-associated antibodies, Ku, PM/Scl, Sjögren’s antibody [SS-A], and Smith [Sm]/U1-RNP antibody, are less specific for polymyositis and dermatomyositis and are found in 1% to 13% of these patients. A positive test result for a myositis-associated antibody in a symptomatic patient suggests the presence of either polymyositis, dermatomyositis (with rash), IMNM, or IBM; overlap myositis is also a possibility.

• #1 Leading Polymyositis Treatment in Brisbane | ArthritisCARE

  https://arthritiscare.com.au/polymyositis/

  Diagnosing polymyositis can be challenging, as the symptoms are similar to those of other conditions. It may also be associated with another autoimmune disease, such as scleroderma, lupus (SLE), rheumatoid arthritis, or Sjogrens syndrome. […] At ArthritisCARE, we use a combination of physical examinations, blood tests, and imaging studies to diagnose polymyositis. In some cases, a muscle biopsy may also be required. […] Blood tests: We can check for an enzyme called creatine kinase (CK), where elevated levels indicate muscle damage. This can be elevated with other conditions too, so we will need to rule those out in order to diagnose polymyositis. We can also test for autoantibodies and muscle-specific antibodies. […] EMG, or electromyography, can identify abnormalities in muscles. […] MRI scans can show areas of muscle that are affected, which shows a surgeon where to get an accurate muscle biopsy. This biopsy is considered the most definitive test for diagnosing polymyositis.

• #1 Idiopathic Inflammatory Myopathies – Musculoskeletal and Connective Tissue Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/systemic-rheumatic-diseases/idiopathic-inflammatory-myopathies

  The overall goal is to rapidly eliminate inflammation but minimize long-term corticosteroid exposure. For acute disease, adults receive oral prednisone approximately 1 mg/kg (up to a maximum of 80 mg) once a day. […] A second medication (typically methotrexate, tacrolimus, or azathioprine) is started at the same time as corticosteroids or shortly after so that prednisone can be tapered, ideally within approximately 6 months. […] Serial measurements of creatine kinase (CK) provide an early guide to therapeutic effectiveness. However, in patients with widespread muscle atrophy, levels are occasionally normal despite chronic, active myositis. […] CK levels usually fall toward or reach normal in 6 to 12 weeks during treatment, followed later by improved muscle strength. […] Unless patients have the characteristic skin findings, do a muscle biopsy to confirm the diagnosis and exclude noninflammatory myopathy.

• #1 Reddit – The heart of the internet

  https://www.reddit.com/r/Autoimmune/comments/17udiqa/recently_diagnosed_with_polymyositiskinda_crazy/

  Im 27 (F) and was recently hospitalized and diagnosed with having polymyositis. […] I had my first appointment with a rheumatologist a week ago and hes a really chill and knowledgeable guy. […] Said my case is VERY rare and something he doesnt see often (I guess also because Im really young too lol). […] I got an OFFICIAL diagnosis from my rheumatologist last month and what im dealing with is called immune mediated necrotizing myopathy, which according to him, is VERY rare and I think hes only known of one other person with my same condition so thatswild.

• #1 Polymyositis – Myositis Association Australia

  https://myositis.org.au/myositis/about-myositis/polymyositis/

  Polymyositis is a connective tissue disease that triggers inflammation and muscular weakness. […] Since symptoms differ between individuals, Polymyositis is hard to diagnose. […] How is Polymyositis diagnosed? Polymyositis is sometimes mistaken for muscular dystrophy, so careful diagnosis is important. Some of the tests for Polymyositis include: Medical history: People with other connective tissue diseases, such as scleroderma, are at greater risk of Polymyositis; Physical examination: including general tests; Electromyography: wires attached to the skin measure the electrical activity of muscles; Muscle biopsy: a small tag of muscle tissue is removed and examined in a laboratory for evidence of degeneration and abnormal immune system activity. This is the gold standard test for Polymyositis; Scans: including magnetic resonance imaging; Blood tests: including an antibody titre because Polymyositis is characterised by the overproduction of particular antibodies. There can also be higher than normal amounts of a muscle enzyme indicating muscle damage (CK creatine phosphokinase) circulating in the bloodstream, which can be measured by a specific blood test; Other tests: to exclude other causes such as bacterial or parasitical infections of muscle tissue.

• #1 Polymyositis: Causes, Symptoms, and Treatment

  https://www.webmd.com/arthritis/polymyositis

  Polymyositis Diagnosis […] There are no simple tests to diagnose polymyositis. It often takes time before doctors know for sure you have it. […] Your doctor will take your medical history to rule out other conditions. They may also test your muscle strength. […] You may also get tests such as: Blood tests: These can help the doctor spot signs of muscle damage. EMG (electromyography): This is used to check if the patterns of electrical impulses in your muscles are normal or not. MRI (magnetic resonance imaging): This uses a magnet to scan and create images of large areas of your muscle. Muscle biopsy: Your doctor will take a small sample of your muscle for testing to see if the muscle tissue is inflamed.

• #1 Successful diagnosis and treatment of canine polymyositis: utilizing MRI and immunohistochemistry for accurate detection | BMC Veterinary Research | Full Text

  https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-024-04356-6

  Additionally, magnetic resonance imaging (MRI) and immunohistochemistry (IHC) are valuable diagnostic tools for polymyositis. […] This case highlights the critical role of MRI and immunohistochemistry in diagnosing immune-mediated polymyositis, demonstrating their alternative capability in cases where conventional electromyography (EMG) is not feasible in this context. […] The immunohistochemistry results for CD4, CD8, and VEGF were positive, indicating a T cell-mediated immune response and angiogenesis in the inflamed lesions. […] Based on the clinical presentation and diagnostic findings, the dog was diagnosed with immune-mediated polymyositis.

• #1 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  The classical myositis-specific antibodies include Jo-1, EJ, OJ, PL-7, and PL-12 synthetase antibodies, which define antisynthetase syndrome, as well as Mi-2 and SRP antibodies. Of these, only Jo-1 antibody is currently included in the EULAR/ACR criteria. Jo-1 antibody is observed in 21% of patients with polymyositis and in 11% of those with antisynthetase syndrome with dermatomyositis-like rash. Because it is 100% specific for IIM, Jo-1 positivity is a major contributor to a definitive IIM diagnosis. The remaining classical myositis-specific antibodies occur less frequently than Jo-1 but are also highly specific (97%-100%) for IIM. Accordingly, a positive test result for any of the classical myositis-specific antibodies is highly suggestive of IIM. A negative test result does not rule out IIM; classical myositis-specific antibodies are not detected in 50% of affected patients.

• #1 Polymyositis Diagnosis | Stanford Health Care

  https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/polymyositis/diagnosis.html

  It takes an experienced doctor to tell the difference between polymyositis and other muscle conditions, like dermatomyositis or inclusion body myositis. […] The process for diagnosing polymyositis may include: […] Complete medical history and physical examination, including history of systemic diseases and careful examination to discern the pattern of muscle involvement. […] Electrodiagnostic tests (EMG/NCS): Our neuromuscular neurologists assess muscle and nerve function using a machine that measures electrical signals in individual muscles and nerves. […] Laboratory tests: Your blood is checked for muscle enzymes, antibodies are associated with autoimmune diseases, and other possible causes of muscle weakness. […] Imaging studies: You may undergo non-invasive testing like magnetic resonance imaging (MRI) to confirm muscle inflammation. […] Muscle biopsy: Examination of a small sample of muscle tissue to look for abnormalities that may establish a diagnosis.

• #2 Diagnosis and differential diagnosis of dermatomyositis and polymyositis in adults – UpToDate

  https://www.uptodate.com/contents/diagnosis-and-differential-diagnosis-of-dermatomyositis-and-polymyositis-in-adults

  Diagnosis and differential diagnosis of dermatomyositis and polymyositis in adults […] The diagnosis and differential diagnosis of DM and „PM” in adults will be reviewed here. […] There is growing understanding that the term PM is falling out of favor given the increased understanding that many cases that would previously have been classified as PM are now better classified as the antisynthetase syndrome (without a characteristic rash), overlap myositis (with another connective tissue disease), or immune-mediated necrotizing myopathy (IMNM). […] While it is now understood that muscle biopsy features are distinct in IMNM, previous studies often labeled these cases as PM, assuming the primary inflammation had been missed on the muscle biopsy sampling.

• #2 Polymyositis Diagnosis | Stanford Health Care

  https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/polymyositis/diagnosis.html

  It takes an experienced doctor to tell the difference between polymyositis and other muscle conditions, like dermatomyositis or inclusion body myositis. […] The process for diagnosing polymyositis may include: […] Complete medical history and physical examination, including history of systemic diseases and careful examination to discern the pattern of muscle involvement. […] Electrodiagnostic tests (EMG/NCS): Our neuromuscular neurologists assess muscle and nerve function using a machine that measures electrical signals in individual muscles and nerves. […] Laboratory tests: Your blood is checked for muscle enzymes, antibodies are associated with autoimmune diseases, and other possible causes of muscle weakness. […] Imaging studies: You may undergo non-invasive testing like magnetic resonance imaging (MRI) to confirm muscle inflammation. […] Muscle biopsy: Examination of a small sample of muscle tissue to look for abnormalities that may establish a diagnosis.

• #2 Polymyositis – Wikipedia

  https://en.wikipedia.org/wiki/Polymyositis

  Polymyositis is an inflammatory myopathy mediated by cytotoxic T cells with an as yet unknown autoantigen, while dermatomyositis is a humorally mediated angiopathy resulting in myositis and a typical dermatitis. […] Diagnosis is fourfold: History and physical examination, elevation of creatine kinase, electromyograph (EMG) alteration, and a positive muscle biopsy. […] The hallmark clinical feature of polymyositis is proximal muscle weakness, with less important findings being muscle pain and dysphagia. […] Sporadic inclusion body myositis (sIBM) is often misdiagnosed as polymyositis or dermatomyositis but it can be differentiated as myositis that does not respond to treatment is likely IBM.

• #2 Polymyositis | Better Health Channel

  https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/polymyositis

  Polymyositis is sometimes mistaken for muscular dystrophy, so careful diagnosis is important. […] Some of the tests for polymyositis include: […] Medical history people with other connective tissue diseases, such as scleroderma, are at greater risk of polymyositis. […] Physical examination this includes general tests. […] Electromyography wires attached to the skin measure the electrical activity of muscles. […] Muscle biopsy a small tag of muscle tissue is removed and examined in a laboratory for evidence of degeneration and abnormal immune system activity. This is the definitive test for polymyositis. […] Scans these include magnetic resonance imaging. […] Blood tests an antibody titre is included, since polymyositis is characterised by the overproduction of particular antibodies. There are also higher than normal amounts of a muscle enzyme indicating muscle damage (creatine phosphokinase) circulating in the bloodstream, which can be measured by a specific blood test. […] Other tests these are used to exclude other causes such as bacterial or parasitical infections of muscle tissue.

• #2 Myositis: Symptoms, Causes, Diagnosis, and Treatment

  https://www.verywellhealth.com/myositis-overview-4778444

  Polymyositis causes muscle weakness on both sides of the body. Having polymyositis makes it hard to climb steps, get up from a seated position, reach overhead, and lift. […] Symptoms of polymyositis develop gradually over weeks or months, and may include: Inflammation and weakness in the muscles responsible for movement, Weakness in the proximal muscles—those closest to the chest and abdomen, although the distal muscles (lower arms, hands, lower legs, feet, etc.) may be affected as the disease progresses, Arthritis, including mild joint or muscle tenderness, Shortness of breath, Problems with swallowing and speaking, Fatigue, Heart arrhythmias—improper heart rhythm, whether irregular, too fast, or too slow. […] A diagnosis of myositis is often difficult to make because the condition is so rare and also because symptoms are common in other conditions. If a healthcare provider suspects myositis, the following tests might be done: Bloodwork: High levels of certain enzymes, such as creatine kinase, indicate muscle inflammation. Other bloodwork can look for abnormal antibodies to identify autoimmune diseases. Magnetic resonance imaging (MRI): This involves a magnetic scanner and a computer to take pictures of muscle tissues. An MRI scan can help identify muscles affected by myositis and changes in those muscles over time. Electromyography (EMG): An EMG measures muscle responses. It is done by inserting needle electrodes into muscles to identify muscles that are weak or damaged by myositis. Muscle biopsy: This is the most accurate method for diagnosing myositis. Once a healthcare provider identifies a weak muscle, they make a small incision and remove a small sample of muscle tissue for testing. The tissue sample will be looked at under a microscope. Different chemicals are used on the tissue sample to identify signs of myositis or another disease.

• #2 Diagnosis – The Myositis Association

  https://www.myositis.org/about-myositis/diagnosis/

  Diagnosing any disease is a bit like solving a mystery. The physician will collect a variety of information and fit this all together to form an understanding about what is causing the patients symptoms. For those with myositis, this process can be challenging for a number of reasons. […] The first step in any diagnosis is a medical history. The doctor will ask questions about your health in general, including detailed personal and family health histories. […] The next step will be a physical examination. The doctor will examine your skin symptoms and test your muscle strength. […] The history and physical will give the doctor some idea about a diagnosis. He or she may then use one or more of the following tests to help confirm a specific diagnosis: […] Blood tests, especially the levels of certain muscle enzymes in the blood, can offer important clues, not only about what may be causing symptoms, but also what is not causing them.

• #2 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Jo-1 Antibody – Diagnose PM/DM […] Lactate Dehydrogenase (LD) – Diagnose PM/DM […] Myositis Specific 11 Antibody Panel – Diagnose PM/DM (Jo-1 provides a more definitive diagnosis) Diagnose IMNM Diagnose cancer-associated DM Diagnose juvenile DM Diagnose amyopathic DM […] Sjogren’s Antibody (SS-A) – Diagnose overlap of PM/DM with Sjögren syndrome, SLE, or systemic sclerosis […] Sm/RNP Antibody – Diagnose overlap of PM with SLE or systemic sclerosis […] On initial evaluation, about 80% to 90% of myositis patients have elevated creatine kinase (CK) associated with muscle damage. Using elevated CK to diagnose IIMs has limitations, however. CK levels may be only slightly elevated, or normal, due to lack of muscle mass or the presence of circulating CK inhibitors or CK antibodies. Normal CK levels may also be observed in patients with IBM, as well as those with juvenile or amyopathic dermatomyositis. Another limitation is that CK and other muscle enzymes are not specific markers of polymyositis/dermatomyositis. Serum elevations may be due to other types of muscle disease (muscular dystrophies, rhabdomyolysis), hypothyroidism, cardiac, or liver disease. Consequently, tests employing antibody markers, rather than muscle enzymes, are used to specifically diagnose and classify IIMs.

• #2 Polymyositis and Dermatomyositis Causes, Symptoms, Treatment, Prevention

  https://www.medicinenet.com/polymyositis/article.htm

  Diagnosis of polymyositis or dermatomyositis […] Various measures of strength might be noted. The characteristic features of polymyositis include weakness of the muscles closest to the trunk of the body, abnormal elevation of muscle enzymes, electromyography (EMG) findings, magnetic resonance imaging (MRI) findings, and certain abnormalities detected with muscle biopsy. […] Blood testing usually (but not always) reveals abnormally high levels of muscle enzymes, CPK or creatinine phosphokinase, aldolase, SGOT, SGPT, and LDH. These enzymes are released into the blood by a muscle that is being damaged by inflammation. […] Electromyography (EMG) and nerve conduction velocity are electrical tests of muscle and nerves that can show abnormal findings typical of polymyositis as well as exclude other nerve-muscle diseases.

• #2 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  The classical myositis-specific antibodies include Jo-1, EJ, OJ, PL-7, and PL-12 synthetase antibodies, which define antisynthetase syndrome, as well as Mi-2 and SRP antibodies. Of these, only Jo-1 antibody is currently included in the EULAR/ACR criteria. Jo-1 antibody is observed in 21% of patients with polymyositis and in 11% of those with antisynthetase syndrome with dermatomyositis-like rash. Because it is 100% specific for IIM, Jo-1 positivity is a major contributor to a definitive IIM diagnosis. The remaining classical myositis-specific antibodies occur less frequently than Jo-1 but are also highly specific (97%-100%) for IIM. Accordingly, a positive test result for any of the classical myositis-specific antibodies is highly suggestive of IIM. A negative test result does not rule out IIM; classical myositis-specific antibodies are not detected in 50% of affected patients.

• #2 Polymyositis – Types, Causes, Symptoms, Complications, Diagnosis, Treatment

  https://www.medindia.net/health/conditions/polymyositis.htm

  Polymyositis is diagnosed based on: […] Blood tests show elevated erythrocyte sedimentation rate (ESR), C-reactive protein and increased white blood cells (leukocytosis), which are all indicative of inflammation. The levels of the enzymes creatine kinase and aldolase are increased, which indicate muscle damage. […] Muscle biopsy shows findings consistent with death and degeneration of muscle tissue and inflammation. […] Electromyography is the testing of muscles electrical activity and shows signs of muscle damage in polymyositis. […] Antibody test: Anti-Jo-1 antibodies are detected in the blood in 20% of cases. […] Urine analysis: Myoglobinuria, i.e. excretion of the protein myoglobin derived from muscles in the urine, is present. […] CT scan is used to detect any associated cancers, which could cause polymyositis. […] Magnetic Resonance Imaging (MRI) is used to evaluate the extent of muscle involvement.

• #2 Polymyositis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK563129/

  The multi-modal approach of hematologic and serologic testing, imaging, electromyography, nerve conduction studies, and biopsy findings is used to evaluate a patient with suspected polymyositis. […] Almost all the patients with PM will have abnormal electromyography (EMG) findings, such as varying amplitude and velocity of the membranous action potential and fibrillation in potentials due to membrane irritability. A vital investigation to make a definitive diagnosis of myopathy is a magnetic resonance imaging, or EMG-guided biopsy that shows perivascular and endomysial mononuclear infiltrates (cytotoxic T lymphocytes and macrophages) and areas of necrosis staining pink due to high eosin stain binding. […] Polymyositis is treated with a combination of different pharmacological and non-pharmacological modalities. Pharmacological treatment mainly includes corticosteroids. Prednisone and methylprednisolone are the most common corticosteroids used for polymyositis, with a starting dose of 1 mg/kg of prednisone a day.

• #2 Polymyositis and Dermatomyositis Causes, Symptoms, Treatment, Prevention

  https://www.medicinenet.com/polymyositis/article.htm

  Imaging of the muscles using radiology tests, such as magnetic resonance imaging (MRI scanning), can show areas of inflammation of muscle. This sometimes can be used to determine optimal muscle biopsy sites. […] A muscle biopsy is used to confirm the presence of muscle inflammation typical only of polymyositis. This is a surgical procedure whereby muscle tissue is removed for analysis by a pathologist, a specialist in examining the tissue under a microscope. Muscles often used for biopsy include the quadriceps muscle of the front of the thigh, the biceps muscle of the arm, and the deltoid muscle of the shoulder.

• #2 Polymyositis – adult: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000428.htm

  Polymyositis and dermatomyositis are rare inflammatory diseases. (The condition is called dermatomyositis when it involves the skin.) These diseases lead to muscle weakness, swelling, tenderness, and tissue damage. They are part of a larger group of diseases called myopathies, more specifically inflammatory myopathies. […] Polymyositis affects the skeletal muscles. It is also known as idiopathic inflammatory myopathy. The exact cause is unknown, but it may be related to an autoimmune reaction or infection. […] Tests may include: […] Autoimmune antibodies and inflammation tests […] Serum CPK (creatine phosphokinase) […] Serum aldolase […] Electromyography […] MRI of affected muscles […] Muscle biopsy […] Myoglobin in the urine […] ECG […] Chest x-ray and CT scan of the chest […] Pulmonary function tests […] Esophageal swallowing study […] Myositis specific and associated autoantibodies. […] A repeat muscle biopsy may be needed to make this diagnosis.

• #2 Polymyositis Workup: Approach Considerations, Imaging Studies, Electromyography

  https://emedicine.medscape.com/article/335925-workup

  Muscle biopsy (eg, deltoid or quadriceps femoris) is crucial in helping to diagnose polymyositis and in excluding other rare muscle diseases. […] Inflammatory changes are seen on muscle biopsy. […] The diagnosis of polymyositis is definite when a patient has subacute elevated levels of serum CK and findings on muscle biopsy consistent with the histologic features of polymyositis.

• #2 Polymyositis / Dermatomyositis Diagnosis and Treatment – Autoimmune Disorders for Medicine

  https://www.picmonic.com/pathways/medicine/courses/standard/pathology-196/autoimmune-disorders-39340/polymyositis-dermatomyositis-diagnosis-and-treatment_2640

  For a definitive diagnosis of PM or DM, a muscle biopsy provides positive confirmation. Biopsy for PM shows CD8+ T-cell infiltration, along with necrotic muscle fibers. Muscle biopsy for DM shows CD4+ T-cell infiltration along with perifascicular atrophy, and a skin biopsy may also support the etiology of the cutaneous features.

• #2 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Myositis: Laboratory Support for Classification and Diagnosis […] This Clinical Focus provides an overview of the use of laboratory testing to classify and diagnose myositis caused by the idiopathic inflammatory myopathies. […] The differential diagnosis of IIMs and overlap myositis begins with the exclusion of muscular dystrophy and myopathies of known cause (eg, infectious, metabolic, drug-induced, or neurologic). Diagnosis is aided by imaging, electromyography, biopsy, testing levels of muscle enzymes in serum, and the detection of myositis-specific and myositis-associated antibodies. In addition, the detection of certain antibodies may have prognostic value. […] Individuals suitable for testing […] Individuals with symptoms of IIM (eg, unexplained muscle weakness, rash, evidence of systemic disease)

• #2 Polymyositis Diagnosis And Treatment – Klarity Health Library

  https://my.klarity.health/polymyositis-diagnosis-and-treatment/

  Polymyositis is a chronic autoimmune disorder in which the immune system attacks and destroys muscles close to the trunk of the body, causing myopathy (muscle disease). […] The diagnosis of polymyositis is a diagnosis of exclusion; that is, it can only be diagnosed if the diagnostic criteria for other idiopathic inflammatory myopathies are not met. […] A comprehensive evaluation is required to diagnose the entire range of myopathies, including polymyositis. […] Different classification criteria have been created to facilitate diagnosis. One that has proven useful and effective is the European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) Classification criteria. […] This EULAR/ACR allows doctors to differentiate between possible, probable and definitive cases of polymyositis.

• #2 Myositis – Polymyositis and Dermatomyositis – Patient.info

  https://patient.info/doctor/myositis-polymyositis-and-dermatomyositis

  Polymyositis produces muscle weakness. It is not painful, although a few patients complain of aches or cramps. […] The diagnosis is established by electromyography (EMG) and is confirmed by muscle biopsy. In polymyositis it is the definitive test. […] Polymyositis is a diagnosis of exclusion and other considerations include: hereditary neuromuscular diseases, endocrine disease including thyrotoxicosis and Cushing’s disease, malabsorption syndromes, alcoholism, cancer, vasculitis, granulomatous disease, sarcoidosis or exposure to drugs or toxins that affect the muscles. […] The prognosis of the idiopathic inflammatory myopathies is very variable. An associated malignancy indicates a poor prognosis for recovery and increases mortality. Overall, drug-free remissions are rare except in juvenile dermatomyositis. Studies have shown that only 20% to 40% of treated patients will achieve polymyositis or dermatomyositis remission, whereas 60% to 80% will experience a polycyclic or chronic continuous course of the disease. Mortality remains 2-3 times higher than in the general population, with cancer, lung, cardiac complications and infections being the most common causes of deaths. Poor prognostic factors include older age, male gender, non-Caucasian ethnicity, longer symptom duration, cardiac involvement, dysphagia, malignancy and serum myositis-specific antibodies (including co-existence of anti-Ro52 and anti-Jo1 antibodies, presence of antisignal recognition particle antibody, anti-155/140, and anti-CADM-140 antibodies). […] The diagnosis is established by electromyography (EMG) and is confirmed by muscle biopsy. In polymyositis it is the definitive test.

• #2

  https://link.springer.com/article/10.1007/s44231-023-00033-8

  Polymyositis (PM), which usually occurs in young and middle-aged females, is an inflammatory myopathy characterized by symmetrical proximal limb weakness, neck muscular weakness, and muscle soreness. […] In this case report, we described the clinical features and pathological clues to help diagnose this disease, furthermore, a review of the literature is provided. […] Serum creatine kinase (CK) level elevated five times above the limit of normal levels and the myositis autoantibody test was positive. […] Typical clinical symptoms and signs, laboratory results, and significant therapeutic efficacy of hormone therapy and biological therapy all revealed PM complicated with rhabdomyolysis (RML) clinically. […] This study was to explore the disease by reviewing one case and literatures, which would help for early diagnosis of this disease and then give a reasonable basis for future treatment. Glucocorticoids are still the first-line treatment for the disease.

• #2 Polymyositis – adult Information | Mount Sinai – New York

  https://www.mountsinai.org/health-library/diseases-conditions/polymyositis-adult

  Polymyositis can affect people at any age. […] Tests may include: Autoimmune antibodies and inflammation tests, Serum CPK (creatine phosphokinase), Serum aldolase, Electromyography, MRI of affected muscles, Muscle biopsy, Myoglobin in the urine, ECG, Chest x-ray and CT scan of the chest, Pulmonary function tests, Esophageal swallowing study, Myositis specific and associated autoantibodies. […] People with this condition also must be watched carefully for signs of cancer. […] A repeat muscle biopsy may be needed to make this diagnosis.

• #2 Polymyositis and Dermatomyositis – Brigham and Women’s Hospital

  https://www.brighamandwomens.org/medicine/rheumatology-inflammation-immunity/services/polymyositis-and-dermatomyositis

  Diagnosis of the inflammatory muscle disease is usually done with a combination of physical examination and lab tests that measure muscle inflammation. […] Other tests that may be needed include: […] Biopsy of the affected muscle to show inflammation. […] MRI, which can show inflammation in the muscle. […] Electromyography (EMG), which can show which muscles are involved. […] Especially when EMG or muscle biopsy is being considered, rheumatologists will consult with a neurologist to determine the best diagnostic plan to guide treatment. […] If there is a suspicion of inflammation of the lung, specific breathing tests that measure lung function (pulmonary function tests) and sometimes a CT scan of the chest may be needed.

• #2 Myositis: Laboratory Support for Classification and Diagnosis | Clinical Focus | Quest Diagnostics Myositis: Laboratory Support for Classification and DiagnosisMyositis: Laboratory Support for Classification and Diagnosis

  https://testdirectory.questdiagnostics.com/test/test-guides/CF_Myositis/myositis-laboratory-support-for-classification-and-diagnosis

  Myositis-specific antibodies for IBM and IMNM have been more recently described: […] cN-1A antibodies target cytosolic 5’-nucleotidase and have been reported to be highly predictive for IBM with high specificity (87%-100%) but wide ranging sensitivity estimates (33%-76%). However, cN-1A antibodies may be detected in some patients with other clinical phenotypes of myositis and other autoimmune diseases, including polymyositis (≤5%), dermatomyositis (≤15%), SLE (10%-20%), and Sjögren syndrome (12%-36%). […] HMGCR antibodies target 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR); positive results correctly identify nearly 100% of patients with IMNM. However, sensitivity for IMNM is about 45%. […] Myositis-associated antibodies, Ku, PM/Scl, Sjögren’s antibody [SS-A], and Smith [Sm]/U1-RNP antibody, are less specific for polymyositis and dermatomyositis and are found in 1% to 13% of these patients. A positive test result for a myositis-associated antibody in a symptomatic patient suggests the presence of either polymyositis, dermatomyositis (with rash), IMNM, or IBM; overlap myositis is also a possibility.

• #2 Polymyositis: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/335925-overview

  In most patients, polymyositis responds well to treatment, although residual weakness occurs in approximately 30% of patients. […] Poor prognostic factors include advanced age, female sex, African-American race, interstitial lung disease, presence of anti-Jo-1 and anti-SRP antibodies, associated malignancy, delayed or inadequate treatment, dysphagia, dysphonia, and cardiac and pulmonary involvement. […] Five-year survival rates in polymyositis have been estimated at more than 80%. Mortality is most often related to associated malignancy or pulmonary complications.

• #2 Idiopathic Inflammatory Myopathies – Musculoskeletal and Connective Tissue Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/systemic-rheumatic-diseases/idiopathic-inflammatory-myopathies

  The overall goal is to rapidly eliminate inflammation but minimize long-term corticosteroid exposure. For acute disease, adults receive oral prednisone approximately 1 mg/kg (up to a maximum of 80 mg) once a day. […] A second medication (typically methotrexate, tacrolimus, or azathioprine) is started at the same time as corticosteroids or shortly after so that prednisone can be tapered, ideally within approximately 6 months. […] Serial measurements of creatine kinase (CK) provide an early guide to therapeutic effectiveness. However, in patients with widespread muscle atrophy, levels are occasionally normal despite chronic, active myositis. […] CK levels usually fall toward or reach normal in 6 to 12 weeks during treatment, followed later by improved muscle strength. […] Unless patients have the characteristic skin findings, do a muscle biopsy to confirm the diagnosis and exclude noninflammatory myopathy.

• #2 Polymyoisitis – Diagnosis – Johns Hopkins RheumTV

  https://rheum.tv/rheumtv/polymyoisitis-diagnosis/

  Diagnosing polymyositis is a step by step process. The physician will start by doing a physical exam to assess their strength, followed by blood tests, an EMG, and a muscle biopsy. […] In this video, Dr. Lisa Christopher-Stine, the Director of the Myositis Center, discusses how polymyositis is diagnosed.

• #3 Polymyositis (PM) – Muscular Dystrophy UK

  https://www.musculardystrophyuk.org/conditions/a-z/polymyositis-pm/

  Polymyositis is now considered a rare diagnosis. […] A new diagnosis of polymyositis is now rare. However, some people may still have a diagnosis of polymyositis if they were diagnosed before changes in understanding. […] Specialists use a clinical examination and one or more tests to make a diagnosis. This may include blood tests, a magnetic resonance imaging (MRI) scan, an electromyography (EMG) test, or sometimes a muscle biopsy. A blood test can look for high levels of creatine kinase (CK), which is a sign of muscle damage. There are no specific antibodies for polymyositis.

• #3 MRI guided muscle biopsy confirmed polymyositis diagnosis in a patient with interstitial lung disease | Annals of the Rheumatic Diseases

  https://ard.bmj.com/content/60/4/423.short

  MRI guided muscle biopsy confirmed polymyositis diagnosis in a patient with interstitial lung disease. […] Idiopathic inflammatory myopathies, such as polymyositis (PM), may present with general symptoms such as fever and fatigue and only minimal muscle weakness, making it difficult to make a definite diagnosis and provide adequate treatment. […] MRI scans of muscles may be helpful in selection of a site for muscle biopsy in patients with suspected inflammatory myopathy when a first muscle biopsy turns out to be negative. Additionally, patients with interstitial lung disease of unknown cause should be tested for muscular function to exclude an associated inflammatory muscle disorder.

• #3 Polymyositis – What is it? How is it treated? – Myositis UK

  https://www.myositis.org.uk/myositis-info/conditions/polymyositis/

  How is polymyositis diagnosed? […] Experienced doctors at a centre familiar to the disease will recognise myositis after a simple examination. It will then need to be confirmed by a combination of blood tests and other tests such as electromyography and muscle biopsies. […] When muscles are damaged they release creatine kinase (CK) and lactate dehydrogenase (LDH) enzymes into the bloodstream. These can be tested for in a routine blood sample. Blood tests alone will not confirm but are a useful starting point. […] An examination of the electrical activity of the muscle, known as electromyography, may be helpful in making a diagnosis. […] A muscle biopsy involves a small piece of muscle tissue being taken (usually under local anaesthetic) and then examined under a microscope.

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