polymyositis

The hallmark of polymyositis is weakness and/or loss of muscle mass in the proximal musculature, as well as flexion of the neck and torso.{{cite journal | vauthors = Strauss KW, Gonzalez-Buritica H, Khamashta MA, Hughes GR | title = Polymyositis-dermatomyositis: a clinical review | journal = Postgraduate Medical Journal | volume = 65 | issue = 765 | pages = 437–43 | date = July 1989 | pmid = 2690042 | pmc = 2429417 | doi = 10.1136/pgmj.65.765.437}} These symptoms can be associated with marked pain in these areas as well. The hip extensors are often severely affected, leading to particular difficulty in climbing stairs and rising from a seated position. The skin involvement of dermatomyositis is absent in polymyositis. Dysphagia (difficulty swallowing) or other problems with esophageal motility occur in as many as 1/3 of patients. Low grade fever and enlarged lymph nodes may be present. Foot drop in one or both feet can be a symptom of advanced polymyositis and inclusion body myositis. The systemic involvement of polymyositis includes interstitial lung disease (ILD) and heart disease, such as heart failure and conduction abnormalities.{{cite journal | vauthors = Zhang L, Wang GC, Ma L, Zu N | title = Cardiac involvement in adult polymyositis or dermatomyositis: a systematic review | journal = Clinical Cardiology | volume = 35 | issue = 11 | pages = 686–91 | date = November 2012 | pmid = 22847365 | doi = 10.1002/clc.22026 | pmc = 6652370 }}

Polymyositis tends to become evident in adulthood, presenting with bilateral proximal muscle weakness often noted in the upper legs due to early fatigue while walking. Sometimes the weakness presents itself as an inability to rise from a seated position without help or an inability to raise one's arms above one's head. The weakness is generally progressive, accompanied by lymphocytic inflammation (mainly cytotoxic T cells).{{citation needed|date=October 2020}}

Polymyositis and the associated inflammatory myopathies have an associated increased risk of cancer.{{cite journal | title=Factors Predicting Malignancy in Patients with Polymyositis and Dermatomyositis: A Systematic Review and Meta-Analysis |author1=Xin Lu |author2=Hanbo Yang |author3=Xiaoming Shu |author4=Fang Chen |author5=Yinli Zhang |author6=Sigong Zhang |author7=Qinglin Peng |author8=Xiaolan Tian |author9=Guochun Wang | journal=PLOS ONE | year=2014 | volume=9 | issue=4 | pages=e94128 | doi=10.1371/journal.pone.0094128 | pmid=24713868 | pmc=3979740|bibcode=2014PLoSO...994128L |doi-access=free }} The features they found associated with an increased risk of cancer were older age, age greater than 45, male sex, difficulty swallowing, death of skin cells, cutaneous vasculitis, rapid onset of myositis (<4 weeks), elevated creatine kinase, higher erythrocyte sedimentation rate and higher C-reactive protein levels. Several factors were associated with lower-than-average risk, including the presence of interstitial lung disease, joint inflammation/joint pain, Raynaud's syndrome, or anti-Jo-1 antibody. The malignancies that are associated are nasopharyngeal cancer, lung cancer, non-Hodgkin's lymphoma and bladder cancer, amongst others.{{cite journal |last1=Hill |first1=C.L. |last2=Zhang |first2=Y. |last3=Sigurgeirsson |first3=B. |last4=Pukkala |first4=E. |last5=Mellemkjaer |first5=L. |last6=Airio |first6=A. |last7=Evans |first7=S.R. |last8=Felson |first8=D.T. |title=Frequency of specific cancer types in dermatomyositis and polymyositis: a population-based study |journal=Lancet |volume=357 |issue=9250 |pages=96–100 |date=January 2001 |pmid=11197446 |doi=10.1016/S0140-6736(00)03540-6 |s2cid=35258253 |url= http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(00)03540-6/abstract |access-date=20 April 2015|url-access=subscription }}

Cardiac involvement manifests itself typically as heart failure and is present in up to 77% of patients.

Interstitial lung disease is found in up to 65% of patients with polymyositis, as defined by HRCT or restrictive ventilatory defects compatible with interstitial lung disease.{{cite journal | vauthors = Fathi M, Dastmalchi M, Rasmussen E, Lundberg IE, Tornling G | title = Interstitial lung disease, a common manifestation of newly diagnosed polymyositis and dermatomyositis | journal = Annals of the Rheumatic Diseases | volume = 63 | issue = 3 | pages = 297–301 | date = March 2004 | pmid = 14962966 | pmc = 1754925 | doi = 10.1136/ard.2003.006122}}

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.{{cite journal | title=Polymyositis, invasion of non-necrotic muscle fibres, and the art of repetition | author=Gerald J D Hengstman, Baziel G M van Engelen | journal=British Medical Journal | year=2004 | volume=329 | issue=7480 | doi=10.1136/bmj.329.7480.1464 | pages=1464–1467 | pmid=15604185 | pmc=535982}}

The cause of polymyositis is unknown and may involve viruses and autoimmune factors. Cancer may trigger polymyositis and dermatomyositis, possibly through an immune reaction against cancer that also attacks a component of muscles.{{cite web |url=http://www.merckmanuals.com/home/bone-joint-and-muscle-disorders/autoimmune-disorders-of-connective-tissue/polymyositis-and-dermatomyositis |title=Polymyositis and Dermatomyositis |first=Rula A. |last=Hajj-ali |work=Merck Manual Home Edition |date=August 2013 |access-date=20 April 2015 |url-status=live |archive-url=https://web.archive.org/web/20150419101643/http://www.merckmanuals.com/home/bone-joint-and-muscle-disorders/autoimmune-disorders-of-connective-tissue/polymyositis-and-dermatomyositis |archive-date=19 April 2015 }} There is tentative evidence of an association with celiac disease.{{cite journal| vauthors=Shapiro M, Blanco DA| title=Neurological Complications of Gastrointestinal Disease. | journal=Semin Pediatr Neurol | year= 2017 | volume= 24 | issue= 1 | pages= 43–53 | pmid=28779865 | doi=10.1016/j.spen.2017.02.001 | type=Review }}

Diagnosis is fourfold: History and physical examination, elevation of creatine kinase, electromyograph (EMG) alteration, and a positive muscle biopsy.{{cite journal | vauthors = Scola RH, Werneck LC, Prevedello DM, Toderke EL, Iwamoto FM | title = Diagnosis of dermatomyositis and polymyositis: a study of 102 cases | journal = Arquivos de Neuro-Psiquiatria | volume = 58 | issue = 3B | pages = 789–99 | date = September 2000 | pmid = 11018813 | doi = 10.1590/S0004-282X2000000500001| doi-access = free }}

The hallmark clinical feature of polymyositis is proximal muscle weakness, with less important findings being muscle pain and dysphagia. Cardiac and pulmonary findings will be present in approximately 25% of cases of patients with polymyositis.{{citation needed|date=October 2020}}

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. sIBM comes on over months to years; polymyositis comes on over weeks to months. Polymyositis tends to respond well to treatment, at least initially; IBM does not.{{citation needed|date=October 2020}}

The first line treatment for polymyositis is corticosteroids. Specialized exercise therapy may supplement treatment to enhance quality of life.{{Cite web |title=Myositis |url=https://medlineplus.gov/myositis.html |access-date=2022-11-18 |website=medlineplus.gov}}

Polymyositis affects females at greater frequency than males.{{Cite web |date=2015-12-18 |title=Signs and Symptoms of Polymyositis (PM) - Diseases |url=https://www.mda.org/disease/polymyositis/signs-and-symptoms |access-date=2023-05-18 |website=Muscular Dystrophy Association |language=en}}

The discovery of several myositis-specific autoantibodies during the past decades has enabled the description of other discrete subsets of diagnosis, specifically the discovery of Antisynthetase syndrome in reducing the number of diagnoses of polymyositis.{{cite journal |last1=Leclair |first1=Valérie |last2=Notarnicola |first2=Antonella |last3=Vencovsky |first3=Jiri |last4=Lundberg |first4=Ingrid E. |title=Polymyositis: does it really exist as a distinct clinical subset? |journal=Current Opinion in Rheumatology |date=November 2021 |volume=33 |issue=6 |pages=537–543 |doi=10.1097/BOR.0000000000000837|pmid=34494607 |s2cid=237443416 }}

• Dan Christensen, painter of abstract art. Died due to heart failure caused by polymyositis.{{cite news|url=https://www.nytimes.com/2007/01/27/obituaries/27christensen.html|title=Dan Christensen, 64, Painter of Abstract Art, Dies|date=27 January 2007|newspaper=The New York Times|access-date=20 April 2015|url-status=live|archive-url=https://web.archive.org/web/20150605102517/http://www.nytimes.com/2007/01/27/obituaries/27christensen.html|archive-date=5 June 2015}}
• Robert Erickson, American composer and teacher who was a leading modernist exponent of "12-tone" composition. Died from the effects of polymyositis.{{cite web |url=http://www.sfgate.com/news/article/OBITUARY-Robert-Erickson-2842509.php |title=Obituary - Robert Erickson |date=29 April 1997 |publisher=SF Gate |access-date=20 April 2015 |url-status=live |archive-url=https://web.archive.org/web/20150101194821/http://www.sfgate.com/news/article/OBITUARY-Robert-Erickson-2842509.php |archive-date=1 January 2015 }}
• Ana Estrada, the first person in Peru to die by euthanasia on 21 April 2024, at the age of 47.
• David Lean, film director.{{cite book| first=George Jr. | last=Stevens |title=Conversations with the Great Moviemakers of Hollywood's Golden Age at the American Film Institute |year=2006|publisher=Knopf |isbn=978-1-4000-4054-4 |page=427}}{{cite book |first=Kevin |last=Brownlow |title=David Lean: A Biography |url=https://books.google.com/books?id=u4AdbfjHZf0C&pg=PT1466 |date=1996 |publisher=Macmillan |isbn=978-1-4668-3237-4 |pages=1466–1467 |access-date=20 April 2015 |url-status=live |archive-url=https://web.archive.org/web/20180113024122/https://books.google.com/books?id=u4AdbfjHZf0C&pg=PT1466 |archive-date=13 January 2018 }}
• Eric Samuelsen, playwright.{{Cite web |title=Noted Latter-day Saint playwright and LGBT ally Eric Samuelsen dies |url=https://www.sltrib.com/artsliving/2019/09/20/noted-lds-playwright-eric/ |access-date=2022-11-18 |website=The Salt Lake Tribune |language=en-US}}
• Victor Manuel Resendiz Ruiz, wrestler.{{citation needed|date=October 2020}}
• Cardinal John Wright{{Cite news |last=Vecsey |first=George |date=1979-08-12 |title=John Cardinal Wright Dies at 70; Top-Ranking American in Vatican |language=en-US |work=The New York Times |url=https://www.nytimes.com/1979/08/12/archives/john-cardinal-wright-dies-at-70-topranking-american-in-vatican-saw.html |access-date=2022-11-18 |issn=0362-4331}}
• Rosita Velazquez, Puerto Rican actress and singer.{{cite web | url=https://prpop.org/biografias/rosita-velazquez/ | title=Rosita Velázquez }}

• Limb girdle syndrome

{{Reflist}}

{{Medical resources

| DiseasesDB = 10343

| ICD10 = {{ICD10|M|33|2|m|30}}

| ICD9 = {{ICD9|710.4}}

| ICDO =

| OMIM =

| MedlinePlus = 000428

| eMedicineSubj = med

| eMedicineTopic = 3441

| eMedicine_mult = {{eMedicine2|emerg|474}}

| MeshID = D017285

| Scholia = Q980926

}}

{{Systemic connective tissue disorders}}

{{Authority control}}

Category:Inflammations

Category:Steroid-responsive inflammatory conditions

Category:Systemic connective tissue disorders