Muscle Diseases Flashcards
What are polymyositis and dermatomyositis?
Idiopathic inflammatory myopathies.
Who would likely present with poly/dermatomyositis?
F:M 2:1, 40-50yo.
What clinical features may be seen in poly/dermatomyositis?
Muscle weakness, insidious onset, worsening over months. Usually symmetrical, proximal. Often specific problems-hair brushing etc. Myalgia in 25-50%
What are common cutaneous features in dermatomyositis?
Gottrons sign, heliotrope rash, shawl sign
What organ involvement bar skin occurs in dermatomyositis?
ILD, resp muscle weakness, dysphagia, myocarditis, fever, wt loss, Raynauds, non-erosive polyarthritis
What is the likelihood of malignancy in dermatomyositis and polymyositis, and what associations occur?
15 % d, 9% p. Ovarian, breast, stomach, lung, bladder and colon cancer-risk greatest in men >45yo
What is the likely history of someone with poly/dermatomyositis?
Tired muscles, functional difficulty, pain, DM, thyroid disease, on steroids/statins, use of alcohol/illicit drugs, wt loss, cough, SOB, Raynauds
What examinations are required in the diagnosis of poly/dermatomyositis?
GALS, confrontational testing, isotonic testing
What blood tests are required in diagnosis of poly/dermatomyositis?
Muscle enzymes eg. Creatine kinase (CK) (10x normal)
Inflammatory markers
Electrolytes, calcium, PTH, TSH (to exclude other causes)
Autoantibodies: ANA, Anti-Jo-1, anti-SRP
What electrical activity test is used in the diagnosis of poly/dermatomyositis?
Electromyography (EMG):
increased fibrillations, abnormal motor potentials, complex repetitive discharges
What biopsy may be used in diagnosis of poly/dermatomyositis?
Muscle biopsy: Definitive test. Perivascular inflammation and muscle necrosis
What imaging may be used in diagnosis of poly/dermatomyositis?
MRI: muscle inflammation, oedema, fibrosis and calcification
What is the treatment of poly/dermatomyositis?
Glucocorticoids Azathioprine Methotrexate Ciclosporin IV immunoglobulin
What is inclusion body myositis?
Patients >50yo, M:F 3:1. Distal muscle weakness, weakness wrist/finger flexors, quads and anterior tibial muscles. Often asymmetrical
What will CK levels in inclusion body myositis be compared to PM?
Lower
What will muscle biopsy in inclusion body myositis show?
Shows inclusion bodies
What patient would likely present with Polymyalgia Rheumatica?
> 50yo, higher in northern regions. May have temporal arteritis/giant cell arteritis
What are the clinical manifestations of PR?
Ache in shoulder and hip girdle
Morning stiffness
Usually symmetrical
Fatigue, anorexia, weight loss and fever may occur
Reduced movement of shoulders, neck and hips
Muscle strength is normal
What is temporal/giant cell arteritis?
Granulomatous arteritis of large vessels. Inflammation of intima, media, adventitia of affected arteries.
What symptoms/signs are present in temporal/giant cell arteritis?
Headache Scalp tenderness Jaw claudication (almost pathognomonic) Visual loss (amaurosis fugax) Tender, enlarged, non-pulsatile temporal arteries
How is temporal/giant cell arteritis diagnosed?
Exclude other diagnoses, raised ESR, plasma viscosity, CRP. Temporal artery biopsy definitive test.
What is the treatment of temporal/giant cell arteritis?
Rapid and dramatic response to low dose steroids
If temporal arteritis higher steroid doses required
Gradual reduction in steroid dose over around 18 months to 2 years
What is Fibromyalgia?
Common cause of chronic MSK pain- no inflammation. Commonly women 22-50yo. May occur after emotional/physical trauma
What are the clinical manifestations of Fibromyalgia?
Pain neck, shoulders, lower back, chest wall
Diffuse and chronic
Varies in intensity
Symptoms worse with exertion, fatigue and stress
Sensation of swelling
Fatigue and poor, unrefreshing sleep
Pins and needles/tingling, headaches, depression, abdominal pain (IBS), poor concentration and memory
What clinical findings are present in Fibromyalgia?
Tenderness on palpitation of soft tissues. 11/18 tender points. No other abnormality of MSK system
How is fibromyalgia diagnosed?
Clinical diagnosis partly- no diagnostic tests. Inflamm markers normal, absence of other explanation of symptoms
What is the treatment of fibromylagia ?
MDT- exercise programme, cognitive behavioural therapy, complementary medicine, anti-depressants, analgesia, gabapentin and pregabalin
What is the treatment for polymyalgia rheumatica?
Low dose steroids (prednisolone 15mg/day)- sometimes used as diagnostic tool. After 18 months should resolve
What infiltration can occur in GCA?
Patchy infiltration by lymphocytes, macrophages and multinucleated giant cells
What can vessel wall thickening in GCA result in?
Arterial luminal narrowing, leading to subsequent distal ischaemia
