II. Types

  1. Type 1: Primary Idiopathic Polymyositis (33%)
  2. Type 2: Primary Idiopathic Dermatomyositis (25%)
  3. Type 3: Neoplasia related
  4. Type 4: Childhood disease with Vasculitis
  5. Type 5: Collagen Vascular disease related
  6. Type 6: Miscellaneous (Inclusion body, Eosinophilic)

III. Diagnostic Criteria

  1. Dermatomyositis Diagnosis
    1. Four or more findings seen in Polymyositis (below)
    2. Cutaneous findings suggestive of Dermatomyositis
  2. Polymyositis Diagnosis (4 or more criteria below)
    1. Proximal Muscle Weakness (trunk, thighs, Shoulders)
    2. Increased serum Creatine Phosphokinase or Aldolase
    3. Muscle pain on grasping or spontaneously
    4. EMG myogenic changes (see Polymyositis Evaluation)
    5. Positive anti-Jo1 Antibody
    6. Nondestructive Arthritis or Arthralgia
    7. Pathologic inflammatory signs
    8. Systemic inflammation signs
      1. Temperature over 37 C at axilla
      2. C-Reactive Protein increased
      3. Erythrocyte Sedimentation Rate >20 mm/hour

IV. Differential Diagnosis

V. Evaluation

VI. Management

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Related Studies

Ontology: Polymyositis (C0085655)

Definition (NCI_NCI-GLOSS) An inflammatory disease of the muscles closest to the center of the body. It causes weakness, inability to stand, climb stairs, lift, or reach. It may also cause muscle pain and difficulty swallowing, and may affect the lungs and heart. Having polymyositis increases the risk of certain types of cancer.
Definition (NCI) An idiopathic inflammatory disorder affecting the muscles. It presents with symmetrical proximal muscle weakness and elevated skeletal muscle enzymes.
Definition (CSP) inflammation of a number of voluntary muscles simultaneously.
Definition (MSH) Diseases characterized by inflammation involving multiple muscles. This may occur as an acute or chronic condition associated with medication toxicity (DRUG TOXICITY); CONNECTIVE TISSUE DISEASES; infections; malignant NEOPLASMS; and other disorders. The term polymyositis is frequently used to refer to a specific clinical entity characterized by subacute or slowly progressing symmetrical weakness primarily affecting the proximal limb and trunk muscles. The illness may occur at any age, but is most frequent in the fourth to sixth decade of life. Weakness of pharyngeal and laryngeal muscles, interstitial lung disease, and inflammation of the myocardium may also occur. Muscle biopsy reveals widespread destruction of segments of muscle fibers and an inflammatory cellular response. (Adams et al., Principles of Neurology, 6th ed, pp1404-9)
Concepts Disease or Syndrome (T047)
MSH D017285
ICD9 710.4
ICD10 M33.2
SnomedCT 15099002, 156457001, 31384009
English Myositis, Multiple, Multiple Myositis, Myositides, Multiple, Polymyositides, polymyositis (diagnosis), polymyositis, Polymyositis, Polymyositis [Disease/Finding], multiple myositis, Neuromyositis-retired, Neuromyositis-retired (disorder), POLYMYOSITIS, Neuromyositis, PM - Polymyositis, Polymyositis (disorder)
French POLYMYOSITE, Myosite multiple, Polymyosite
Portuguese POLIMIOSITE, Polimiosite, Miosite Múltipla
Spanish POLIMIOSITIS, neuromiositis - RETIRADO - (concepto no activo), neuromiositis - RETIRADO -, polimiositis (trastorno), polimiositis, Polimiositis, Miositis Múltiple
German POLYMYOSITIS, Myositis, Poly-, Polymyositis
Swedish Polymyosit
Japanese タハツセイキンエン, 筋炎-多発, 筋炎-多発性, 多発性筋炎, 多発筋炎
Czech polymyozitida, Polymyozitida, polymyositida, polymyositis
Finnish Polymyosiitti
Korean 다발성근육염
Croatian Not Translated[Polymyositis]
Polish Zapalenie mięśni mnogie, Zapalenie wielomięśniowe
Hungarian Polymyositis
Norwegian Polymyositt
Dutch polymyositis, Myositis, multipele, Polymyositis
Italian Polimiosite