Polymyositis & Dermatomyositis Flashcards
1
Q
What is Polymyositis and Dermatomyositis?
A
- Polymyositis
- Condition of chronic inflammation of muscles
- Dermatomyositis
- Chronic inflammation of skin and msucles
2
Q
What are the Sx of P&D?
A
- Muscle pain, fatigue and weakness
- Occurs bilaterally and typically affects the proximal muscles
- Mostly affects the shoulder and pelvic girdle
- Develops over weeks
- Dysphagia
3
Q
What are the skin clinical features of D?
A
- Macular rash
- Heliotrop rash on eyelids
- Nailfold erythema
- Gottron’s papules
4
Q
What are Gottron’s papules?
A
- roughened red papules over knuckles, elbows, knee
5
Q
What are the extramusclular signs seen for both P&D?
A
- fever
- arthralgia
- Raynaud’s
- ILD
- Myocarditis
- Arrythmias
6
Q
What Ix would you order for P&D?
A
- Bloods
- Muscle enzymes
- CK >1000
- ALT, AST, LDH, aldolase
- Autoantibodies
- Anti-Jo-1 antibodies: polymyositis (but often present in dermatomyositis)
- Anti-Mi-2 antibodies: dermatomyositis.
- Anti-nuclear antibodies: dermatomyositis
- Muscle enzymes
- MRI - muscle oedema in acute myositis
- Muscle biopsy
7
Q
What are the other causes of elevated CK?
A
- Rhabdomyolysis
- Acute kidney injury
- Myocardial infarction
- Statins
- Strenuous exercise
8
Q
P&D can be caused by underlying malignancy. What are the most common associated cancers?
A
- Lung
- Breast
- Ovarian
- Gastric
9
Q
What are the differential diagnosis for P&D?
A
- Carcinomatous myopathy
- Inclusion body myositis
- muscular dystrophy
- endocrine myopathy
- rhabdomyolysis
- infection - HIV
- drugs
- penicillamine
- colchicine
- statins
- chloroquine
10
Q
How would you mx P&D?
A
- Prednisolone - first line tx
- Immunosuppressants (such as azathioprine)
- IV immunoglobulins
- Biological therapy (such as infliximab or etanercept)
- Hydroxychloroquine/topical tacrolimus for skin disease
