Polymyositis: Difference between revisions

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==Background==
==Background==
Idiopathic inflammatory myopathy causing symmetric proximal muscle weakness, elevated CK,and characteristic EMG findings
*Idiopathic inflammatory myopathy causing symmetric proximal muscle weakness, elevated CK,and characteristic EMG findings


==Clinical Features==
==Clinical Features==
*Symmetrical proximal muscle weakness with insidious onset
*Symmetrical proximal muscle [[weakness]] with insidious onset
*Generally painless (though 30% have myalgia)  
*Generally painless (though 30% have [[myalgia]])  
*Difficulty with kneeling, climbing stairs, combing hair, or rising from a seated position
*Difficulty with kneeling, climbing stairs, combing hair, or rising from a seated position
*Weak neck extensors causing difficulty of holding head up
*Weak neck extensors causing difficulty of holding head up
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==Differential Diagnosis==
==Differential Diagnosis==
*Hypokalemia
{{Myalgia DDX}}
*Hypophosphatemia
*Thyroid disorder (hypothyroidism or hyperthyroidism)
*Myopathies
*Inclusion body myositis
*Drug Induced myopathies (EtOH, antimalarials, colchicine, antifungals)


{{Weakness DDX}}
{{Weakness DDX}}
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*CRP
*CRP
*CK
*CK
*UA
*[[Urinalysis]]
*Consider:
*Consider:
**RF
**RF
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==References==
==References==
<references/>


<references/>
[[Category:Rheumatology]]
[[Category:Rheumatology]]
[[Category:Neurology]]
[[Category:Neurology]]

Revision as of 04:27, 3 October 2019

Background

  • Idiopathic inflammatory myopathy causing symmetric proximal muscle weakness, elevated CK,and characteristic EMG findings

Clinical Features

  • Symmetrical proximal muscle weakness with insidious onset
  • Generally painless (though 30% have myalgia)
  • Difficulty with kneeling, climbing stairs, combing hair, or rising from a seated position
  • Weak neck extensors causing difficulty of holding head up
  • Associated arthralgias

Differential Diagnosis

Myalgia

Weakness

Evaluation

  • CBC
  • ESR
  • CRP
  • CK
  • Urinalysis
  • Consider:
    • RF
    • ANA
    • Anti-Jo-1

Management

  • Prednisone 1mg/kg/day for 4-8 weeks until CK returns to reference range
  • Other treatments that rheum may prescribe:
    • Methotrexate as second line for poor response to corticosteroids
    • Other agents with less evidence: IVIG, TNF Inhibitors

Disposition

  • Rheumatology or neurology consultation either in ED or as outpatient depending on severity of symptoms
  • Very strongly associated with malignancy (~30%), especially:[1]
    • Ovarian
    • Lung
    • Pancreatic
    • Stomach
    • Colorectal
    • Lymphoma
    • Bladder

See Also

References

  1. Hill CL et al. Frequency of specific cancer types in dermatomyositis and polymyositis: a population-based study. Lancet. 2001 Jan 13;357(9250):96-100.