Muscle Diseases Flashcards
What are inflammatory myopathies characterised by?
Weakness
What is polymyalgia rheumatica characterised by?
Pain and stiffness
What is fibromyalgia characterised by?
Pain and fatigue
Define myopathy
Disease of the muscle in which the fibres do not function properly
What condition is polymyositis often associated with?
Dermatomyositis
What causes polymyositis?
Idiopathic, autoimmune inflammatory myopathy
Who tends to get polymyositis?
40-50 year old females
State the increased risk in men with polymyositis
> 45 years old increased risk of malignancy
What are the clinical features of polymyositis?
Muscle weakness, insidious onset worsening over months, symmetrical pattern affecting proximal muscles
What are the three signs of dermatomyositis?
Gorton's sign (hands) Heliotrope sign (face) Shawl sign (neck and back)
Name three other organs polymyositis can affect
- lung
- oesophagus
- heart
Name two special tests used to confirm polymyositis
Confrontational test - push down on flexed forearm
Isotonic test - 30 sit to stand
What are the investigations carried out for polymyositis?
Bloods
Electromyography
Muscle biopsy
MRI
What blood tests should be carried out for polymyositis?
Creatine kinase
Inflammatory markers
Electrolytes, Calcium, TSH, PTH
Autoantibodies - ANA and Anti-Jo1
What will electromyography of polymyositis show?
Increased fibrillations, abnormal motor potentials and complex repetitive discharges
What is the definitive test for polymyositis?
Muscle biopsy - shows perivascular inflammation and muscle necrosis
What will an MRI of polymyositis show?
Muscle inflammation, oedema, fibrosis and calcification
How is polymyositis treated?
Corticosteroids and immunosuppressants
Describe the epidemiology of polymyalgia rheumatica
Usually in over 50 year olds with a higher incidence in northern regions
What is polymyalgia rheumatica associated with?
Temporal arterities/giant cell arterities
Describe the clinical features of polymyalgia rheumatica
Ache in shoulder and hip girdle, morning stiffness. Often symmetrical with reduced movement of shoulders neck and hip. Strength is normal.
What are the features of granulomatous arterities?
Headache Scalp tenderness Jaw Claudication Visual loss Tender/enlarged/pulseless arteries
How is polymyalgia rheumatica diagnosed?
Raised ESR/PV/CRP
Temporal artery biopsy and ultrasound
How is polymyalgia rheumatica treated?
Low dose steroids - prednisolone 15mg/day
Gradually reduce steroids over 18 months - after 2 years symptoms are usually gone
What is fibromyalgia?
Commonest cause of chronic MSK pain in women 22-50 years old - not associated with inflammation but may begin after emotional or physical trauma
Explain the pathogenesis of fibromyalgia
- Pre-existing factors
- Precipitating factors
- Pain/Fatigue/Depression
- Decreased serotonin and endorphins
Leads to skin hyperactivity, muscle contraction and reconditioning
What are the symptoms of fibromyalgia?
Fatigue, pain, twitches, morning stiffness, various central symptoms
Tender points - neck, hips, knees, elbows, scapula
What criteria is used to diagnose fibromyalgia?
ACR
- widespread pain and symptoms
- symptoms have been the same for >3months
- no other condition explains the pain
How is fibromyalgia treated?
Education, CBT, complementary medicine, anti-depressants, analgesia, graded exercise programme
