Polymyositis: Difference between revisions

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==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
* Associated arthralgias
*Associated arthralgias


==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}}


==Diagnosis==
==Evaluation==
* CBC, ESR, CRP, CK, UA, RF, ANA, Anti-Jo-1
*CBC
*ESR
*CRP
*CK
*[[Urinalysis]]
*Consider:
**RF
**ANA
**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
**Followed by [[prednisone]] taper
* Methotrexate as second line for poor response to corticosteroids
*Other treatments that rheum may prescribe:
* Other agents with less evidence: IVIG, TNF Inhibitors
**[[Methotrexate]] as second line for poor response to corticosteroids
**Other agents with less evidence: IVIG, TNF Inhibitors


==Disposition==
==Disposition==
* Rheumatology or neurology consultation either in ED or as outpatient depending on severity of symptoms
*Rheumatology or neurology consultation either in ED or as outpatient depending on severity of symptoms
*Very strongly associated with malignancy (~30%), especially:<ref>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.</ref>
**Ovarian
**Lung
**Pancreatic
**Stomach
**Colorectal
**Lymphoma
**Bladder
 
==See Also==
*[[Weakness]]


==References==
==References==
Tintinalli
<references/>


[[Category:Rheum]]
[[Category:Rheumatology]]
[[Category:Neuro]]
[[Category:Neurology]]

Revision as of 00:59, 2 April 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.