Polymyositis & Dermatomyositis Flashcards
What is polymyositis?
Characterised by:
1) symmetrical, proximal muscle weakness, and
2) inflammation of skeletal muscles.
Clinical presentation of polymyositis?
1) Progressive muscle weakness: predominantly affecting the shoulder and pelvic girdles
2) Dysphagia
3) Dyspnoea
4) Arthralgias
5) Myalgias
6) Raynaud’s phenomenon
What muscles are primarily affected in polymyositis?
Shoulder & pelvic girdles
Investigations in polymyositis?
1) CK –> elevated
2) Other muscle enzymes e.g. LDH, AST, ALT –> elevated
3) EMG
4) Mulsce biopsy
What is dermatomyositis?
An inflammatory disorder causing symmetrical, proximal muscle weakness and characteristic SKIN LESIONS.
Are skin lesions seen in polymyositis or dermatomyositis?
Dermatomyositis
polymyositis is a variant of dermatomyositis where skin manifestations are not prominent
Skin features of dermatomyositis?
1) Photosensitive
2) Macular rash over back and shoulders
3) Heliotrope rash in periorbital region
4) Gottron’s papules
5) Extremely dry and scaly hands with linear ‘cracks’ on the palmar and lateral aspects of the fingers
What are Gottron’s papules?
roughened red papules over extensor surfaces of fingers
Other features of dermatomyositis?
Same as polymyositis:
1) proximal muscle weakness +/- tenderness
2) Raynaud’s
3) respiratory muscle weakness
4) interstitial lung disease: e.g. Fibrosing alveolitis or organising pneumonia
5) dysphagia, dysphonia
What antibodies are found in 80% of patients with dermatomyositis?
ANA
Investigations in dermatomyositis?
1) ANA antibodies –> +ve
2) CK –> elevated
3) Skin & muscle biopsy –> to confirm
What investigation may be useful in distinguising myopathy from neuropathy?
Electromyography
Mx of dermatomyositis?
Prednisolone
