Polymyositis and Dermatomyositis

Question 1

Aetiology (3)

Answer 1

1. Viruses (IM, EBV)
2. Autoimmune
3. Cancer

Question 2

Time frame of polymyositis presentation

Answer 2

Weeks to months

Question 3

Polymyositis is associated with ____ disease

Answer 3

Interstitial lung disease

Question 4

Presentation of polymyositis (5)

Answer 4

Muscle pain, systemic proximal muscle weakness, dysphagia, low grade fever, peripheral adenopathy

Question 5

Presentation of dermatomyositis (5)

Answer 5

Systemic proximal muscle weakness, dysphagia, rash (Gottron’s, heliotrope/iliac, Shawl/V), mechanic’s hands, calcinosis cutis

Question 6

Main differential for polymyositis and how you tell the difference

Answer 6

Sporadic inclusion body myositis (sIBM) - comes on in months to years

Question 7

Antibodies positive in dermatomyositis

Answer 7

ANA, anti-Mi-2

Question 8

Antibodies positive in polymyositis

Answer 8

ANA, anti-Jo-1

Question 9

Investigations for polymyositis/dermatomyositis (3)

Answer 9

1. Creatine kinase
2. Electromyograph
3. Muscle biopsy (lymphocyte aggregates, perifascicular muscle fibre atrophy)

Question 10

Management of polymyositis

Answer 10

Steroids and exercise therapy

Question 11

Complications of polymyositis (2)

Answer 11

Heart failure

Increased risk of NHL and lung and bladder cancers