Muscle Diseases Flashcards
What is the pathophysiology of polymyositis?
T cell mediated destruction of muscle
What are the clinical features of polymyositis?
Symmetrical muscle weakness in PROXIMAL upper and lower limbs --> difficulty climbing stairs, brushing hair etc Insidious onset Dysphagia in 1/3 (poor prognosis) Interstitial lung disease (5-30%) Increased risk of malignancy
What are the clinical features of dermatomyositis?
Same as polymyositis + cutaneous features:
- heliotrope rash (around eyes)
- Gottron’s papules on hands (over knuckles)
- V-shaped rash over chest, ‘shawl sign’ rash over upper back
Which investigations should be done for poly/dermatomyositis? Which is definitive?
Bloods
EMG (abnormal in 90%)
Muscle biopsy –> definitive diagnosis
MRI
Which blood tests should be done for poly/dermatomyositis? What would they show?
Inflammatory markers –> raised
CK –> raised
Autoantibodies:
- anti-Jo-1, anti-SRP –> specific for myositis
- ANA, anti-RNP –> seen in other conditions
What would be seen on muscle biopsy in myositis?
Perivascular inflammation + muscle necrosis
What is the management of myositis?
Corticosteroids --> prednisolone Immunosuppression: - azathioprine - methotrexate - ciclosporin - IV Ig - rituximab
Patients with myositis are at an increased risk of which malignancies?
Breast Ovarian Lung Colon Oesophagus Bladder --> screen at time of diagnosis
What are the clinical features of fibromyalgia?
Persistent (> 3 months) widespread pain/tenderness
–> both sides of body, above + below waist, including axial spine
Fatigue
Disrupted + unrefreshing sleep
Cognitive difficulties
Other unexplained symptoms e.g. anxiety, depression, functional impairment
Which other conditions is fibromyalgia associated with?
Depression
IBS
Migraine
How is fibromyalgia diagnosed?
Clinically
How is fibromyalgia managed?
Patient education + validation Graded exercise programme CBT Alternative therapies e.g. acupuncture Atypical analgesics e.g. amitriptyline, pregabalin, gabapentin
What are the clinical features of polymyalgia rheumatica?
Proximal myalgia of hip and shoulder girdles
–> muscle strength normal
+ morning stiffness > 1 hour
Tend to improve throughout the day + with movement
Who gets polymyalgia rheumatica?
Elderly, very rare < 50 yrs
Which other condition in polymyalgia rheumatica strongly associated with?
Giant cell/temporal arteritis
