Inflammatory Myopathies Flashcards

1
Q

What is dermatomyositis?

What is its mechanism?

A

Autoimmune antibody-mediated vasculopathy leading to muscle damage

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2
Q

What are the clinical features of dermatomyositis?

A

Muscle:

  • proximal muscle weakness (bilateral)
  • difficulty climbing stairs or raise things with arms

Dermatologic:

  • heliotrope rash (periorbital edema w/ purple upper eyelids)
  • malar rash
  • Gottron papules (erythematous papules on extensor surfaces of hands, elbows, and knees)
  • poikiloderma or “shawl sign” (erythema of neck, shoulders, and upper chest/back; area covered by a shawL)
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3
Q

What is the epidemiology of dermatomyositis?

A
  • twice as likely in females
  • bimodal age distribution; childhood (5-15) and older adults (40-60)
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4
Q

What are expected lab and biopsy findings with dermatomyositis?

A

Lab:

  • increased CK/aldolase
  • positive ANA (anti-Jo-1 and anti-M2)

Muscle biopsy:

  • perifascicular atrophy
  • perimysial and perifascicular inflammation (CD4+ T cells)
  • perimysium is the outer layer and closest to the skin; dermatomyositis has skin involvement
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5
Q

What is the treatment/management for dermatomyositis?

A

-corticosteroids

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6
Q

What is an associated condition with dermatomyofibrosis?

A

malignancy in 15-24% -> paraneoplastic dermatomyositis

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7
Q

What are potential complications of dermatomyositis?

A
  • dysphagia (33%)
  • interstitial lung disease (10%)
  • cardiac involvement is common but cardiac failure is rare
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8
Q

What is polymyositis?

What is its mechanism?

A

Autoimmune cell-mediated condition resulting in muscle damage (vasculature spared compared to dermatomyositis)

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9
Q

What are the clinical features of polymyositis?

A
  • proximal muscle weakness (bilateral)
  • difficulty climbing stairs or raise things with arms

NO SKIN INVOLVEMENT

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10
Q

What is the epidemiology of polymyositis?

A
  • twice as likely in females
  • mid to older adults (30-60)
  • African American
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11
Q

What are expected lab and biopsy findings with polymyositis?

A

Lab:

  • increased CK/aldolase
  • positive ANA (anti-Jo-1)

Muscle biopsy:

  • necrotic muscle fibers
  • endomysial and intrafascicular inflammation (CD8+ T cells)
  • endomysium is the inner layer and furthest from skin; polymyositis has no skin involvement
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12
Q

What is the treatment/management for polymyositis?

A

-corticosteroids

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13
Q

What is inclusion body myositis?

A

Autoimmune cell-mediated? inflammatory myopathy

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14
Q

What are the clinical features of inclusion body myositis?

A

Muscle:

-distal muscle and quadriceps weakness (bilateral)

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15
Q

What is the epidemiology of inclusion body myositis?

A
  • twice as likely in males
  • older adults (>50)
  • caucasian
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16
Q

What are expected lab and biopsy findings with inclusion body myositis?

A

Lab:

  • increased CK/aldolase
  • positive ANA (anti-cN1A)

Muscle biopsy:

  • rimmed vacuoles
  • endomysial inflammation (CD8+ T cells)