Flashcards in Seminar G Dermatomyositis and Polymyositis Deck (17):
Polymyositis is an autoimmune disease characterised by inflammation of striated muscle.
2-10 per million/yr
Peak mean ages
Childhood and 40-50 years
Aetiology and Pathogenesis
Associations with HLA-DR3 and Drw52
First degree relatives
More common in winter and spring
Drug induced myositis
HMG-CoA reductase inhibitors (Statins)
Painless proximal muscle weakness
More advanced disease
Pharyngeal musculature result difficulty in initiating swallowing, whilst exertional dyspnoea may result from respiratory muscle weakness.
MRC motor scale
May be used to record muscle power
Acute phase response, with a raised ESR or plasma viscosity
Muscle enzymes will be grossly elevated, as they leak from damaged skeletal muscle.
Creatine Kinase (CK)
Most sensitive and best guide to muscle inflammation, but other enzymes such as lactate dehydrogenase, and the transaminases (ALT and AST) may
Autoimmune profile may show
Positive Antinuclear (ANA) and anti-Jo-1 antibodies may also be present.
Treatment → Symptoms
Treatment → Other Agents
Treatment → Prevent glucocorticoid-induced osteoporosis