Polymyositis

Source: Wikipedia, the free encyclopedia.
Not to be confused with
poliomyelitis
.
Polymyositis
Micrograph of polymyositis. Muscle biopsy. H&E stain.
SpecialtyRheumatology

Polymyositis (PM) is a type of chronic inflammation of the muscles (inflammatory myopathy) related to dermatomyositis and inclusion body myositis. Its name means 'inflammation of many muscles' (poly- + myos- + -itis). The inflammation of polymyositis is mainly found in the endomysial layer of skeletal muscle, whereas dermatomyositis is characterized primarily by inflammation of the perimysial layer of skeletal muscles.[1]

Signs and symptoms

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.

conduction abnormalities.[2]

Polymyositis tends to become evident in adulthood, presenting with bilateral proximal

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
]

Associated illnesses

Polymyositis and the associated inflammatory myopathies have an associated increased risk of

non-Hodgkin's lymphoma and bladder cancer, amongst others.[4]

Cardiac involvement manifests itself typically as heart failure and is present in up to 77% of patients.[2] 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.[5]

Causes

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.[6]

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.

celiac disease.[8]

Diagnosis

Diagnosis is fourfold: History and physical examination, elevation of

electromyograph (EMG) alteration, and a positive muscle biopsy.[9]

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]

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]

Treatment

The first line treatment for polymyositis is

corticosteroids. Specialized exercise therapy may supplement treatment to enhance quality of life.[10]

Epidemiology

Polymyositis affects females at greater frequency than males.[11]

Polymyositis as a distinct diagnosis

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.[12]

Society and culture

Notable cases

See also

References

  1. ^
    PMID 2690042
    .
  2. ^
    PMID 22847365
    .
  3. ^
    PMID 24713868
    .
  4. S2CID 35258253
    . Retrieved 20 April 2015.
  5. PMID 14962966
    .
  6. PMID 15604185
    .
  7. ^ Hajj-ali, Rula A. (August 2013). "Polymyositis and Dermatomyositis". Merck Manual Home Edition. Archived from the original on 19 April 2015. Retrieved 20 April 2015.
  8. PMID 28779865
    .
  9. PMID 11018813
    .
  10. ^ "Myositis". medlineplus.gov. Retrieved 2022-11-18.
  11. ^ "Signs and Symptoms of Polymyositis (PM) - Diseases". Muscular Dystrophy Association. 2015-12-18. Retrieved 2023-05-18.
  12. S2CID 237443416
    .
  13. ^ "Dan Christensen, 64, Painter of Abstract Art, Dies". The New York Times. 27 January 2007. Archived from the original on 5 June 2015. Retrieved 20 April 2015.
  14. ^ "Obituary - Robert Erickson". SF Gate. 29 April 1997. Archived from the original on 1 January 2015. Retrieved 20 April 2015.
  15. ISBN 978-1-4000-4054-4
    .
  16. ISBN 978-1-4668-3237-4. Archived
    from the original on 13 January 2018. Retrieved 20 April 2015.
  17. ^ "Noted Latter-day Saint playwright and LGBT ally Eric Samuelsen dies". The Salt Lake Tribune. Retrieved 2022-11-18.
  18. ISSN 0362-4331
    . Retrieved 2022-11-18.
  19. ^ "Rosita Velázquez".

External links

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