polymyositis

Question 1

What is polymyositis?

Answer 1

inflammatory disorder causing symmetrical, proximal muscle weakness

Question 2

What cells mediate the inflammation in polymyositis

Answer 2

T-cell mediated cytotoxic process directed against muscle fibres

Question 3

Causes of polymyositis

dermatomyositis is a
typically affects middle-aged, female:male 3:1

Answer 3

1. idiopathic
2. associated with connective tissue disorders
3. associated with malignancy

Question 4

Name the variant of polymyositis where skin manifestations are prominent, for example a purple (heliotrope) rash on the cheeks and eyelids

Answer 4

Dermatomyositis

Question 5

Clinical features of polymyositis

Answer 5

• proximal muscle weakness +/- tenderness
• Raynaud’s
• respiratory muscle weakness
• interstitial lung disease
• dysphagia/dysphonia

Question 6

investigation findings

Answer 6

• raised CK
• raised lactate
• EMG
• muscle biopsy

Question 7

Antibodies found in polymyositis

Answer 7

Anti-synthetase antibodies

Anti-Jo-1 antibodies are seen in pattern of disease associated with lung involvement, Raynaud’s and fever

Question 8

Management of polymyositis

Answer 8

high-dose steroids
- tapered as symptoms improve

azathioprine may be used as a steroid-sparing agent