Poly/dermatomyositis Flashcards
What is poly/dermatomyositis?
rare condition characterised by the insidious onset of progressive symmetrical proximal muscle weakness
What is the cause of poly/dermatomyositis?
- autoimmune mediated inflammation of striated muscl
2. conditions (especially dermatomyositis) are quite often paraneoplastic phenomena
What is the patho of polymyositis?
Endomysial inflammation with CD8+ T cells
What does polymyositis usually involve?
shoulders
What is the patho of dermatomyositis?
- Perimysial inflammation with CD4+ T cells.
2. Membrane attack complex causes destruction
What is the presentation of polymyositis?
Progressive symmetrical muscle weakness
What are the signs associated with dermatomyositis?
- Gottron’s papules
- facial erthyema
- shawl rash
- mechanical hands
What are Gottron’s papules in dermatomyositis?
rough red papules across knuckles, knees and elbows
What is facial erythema like in dermatomyositis?
Heliotrope rash of eyelids
What is shawl rash like in dermatomyositis?
shoulders and chest darkening
What are the mechanical hands like in dermatomyositis?
Dark and thick irregular patches
What investigations are done?
1, Muscle enzymes
- EMG
- Muscle biopsy
- Autoantibodies
What do muscle enzymes show in poly/dermatomyositis?
CK and Aldolase evelated
What does EMG show in poly/dermatomyositis?
fibrillation potentials
What do muscle biopsy show in poly/dermatomyositis?
can confirm diagnosis by visualising inflammation
