Difference between revisions of "Polymyositis"

(Text replacement - "==Diagnosis==" to "==Evaluation==")
 
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==Background==
 
==Background==
Idiopathic inflammatory myopathy causing symmetric proximal muscle weakness, elevated CK,and characteristic EMG findings
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*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
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*Symmetrical proximal muscle [[weakness]] with insidious onset
*Generally painless (though 30% have myalgia)  
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*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
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{{Myalgia DDX}}
*Hypophosphatemia
 
*Thyroid disorder (hypothyroidism or hyperthyroidism)
 
*Myopathies
 
*Inclusion body myositis
 
*Drug Induced myopathies (EtOH, antimalarials, colchicine, antifungals)
 
  
 
{{Weakness DDX}}
 
{{Weakness DDX}}
  
 
==Evaluation==
 
==Evaluation==
*CBC, ESR, CRP, CK, UA, RF, ANA, Anti-Jo-1
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*CBC
 +
*ESR
 +
*CRP
 +
*CK
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*[[Urinalysis]]
 +
*Consider:
 +
**RF
 +
**ANA
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**Anti-Jo-1
  
 
==Management==
 
==Management==
 
*[[Prednisone]] 1mg/kg/day for 4-8 weeks until CK returns to reference range
 
*[[Prednisone]] 1mg/kg/day for 4-8 weeks until CK returns to reference range
**Followed by prednisone taper
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**Followed by [[prednisone]] taper
 
*Other treatments that rheum may prescribe:
 
*Other treatments that rheum may prescribe:
 
**[[Methotrexate]] as second line for poor response to corticosteroids
 
**[[Methotrexate]] as second line for poor response to corticosteroids
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**Lymphoma
 
**Lymphoma
 
**Bladder
 
**Bladder
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 +
==See Also==
 +
*[[Weakness]]
  
 
==References==
 
==References==
 +
<references/>
  
<references/>
 
 
[[Category:Rheumatology]]
 
[[Category:Rheumatology]]
 
[[Category:Neurology]]
 
[[Category:Neurology]]

Latest 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.