Polymyositis & Dermatomyositis Flashcards
What is Polymyositis?
Striated muscle inflammation
What is associated with Polymyositis?
Myalgia
Arthralgia
What can commonly cause Polymyositis?
Cancer of the Bowel, Lung, Pancreas or Ovaries
Often a paraneoplastic syndrome
What are the main features of Polymyositis?
Progressive and symmetrical muscle weakness Wasting of shoulder and pelvic girdle Dysphagia Dysphonia Respiratory weakness *More common in females*
What is Dermatomyositis?
Myositis and skin changes
What skin changes can occur in Dermatomyositis?
Heliotrope rash (On eyelids, may have oedema)
Macular rash (Shawl sign - over back/shoulders)
Nailfold erythema (Also in SLE)
Gottron’s papules (Knuckles, elbows, knees)
Mechanics hands (Painful cracking skin)
Retinopathy (Haemorrhaging and cotton wool spots)
Subcutaneous calcifications
What are some of the extra muscular features that can occur in Polymyositis/Dermatomyositis?
Fever Arthritis Bibasal pulmonary fibrosis Raynaud's phenomenon Myocarditis Arrhythmias
What investigations can be done in a patient with suspected Polymyositis/Dermatomyositis?
Muscle enzymes - Creatinine kinase, AST, ALT, LDH
Antibodies - Anti Jo1 - Associated with extra muscular features
EMG - Measures electrical activity in skeletal muscle
Muscle biopsy
Screen for malignancy
What is important to check for when investigating a patient for Polymyositis/Dermatomyositis?
Cancer as common paraneoplastic syndrome
Tumour markers, CXR, mammogram, Pelvic/Abdo US, CT
What are some of the differentials for Polymyositis/Dermatomyositis?
Muscular dystrophy
Polymyalgia rheumatica
Drugs - Steroids, Statins, Colchine
What is the management for Polymyositis/Dermatomyositis?
Screen for malignancy
Immunosuppression - Steroids, cytotoxics eg Azathioprine Methotrexate
