Muscle diseases Flashcards
What are the typical presentations of polymyalgia rheumatica (PMR)?
PAIN & STIFFNESS
Ache in shoulder and hip girdle
Morning stiffness
Usually symmetrical
Systemic presentation: Fatigue, anorexia, weight loss and fever may occur
Reduced movement of shoulders, neck and hips
Muscle strength is normal
What is polymyalgia rheumatica?
Most commonly 50-60 y/o
Quite common
Incidence higher in northern regions
Associated with temporal arteritis/ giant cell arteritis (15%)
How is blood test used for diagnosing PMR?
Inflammatory markers are the only abnormal indicators (Raised ESR, plasma viscosity, CRP), no antibody abnormalities
How to manage PMR?
Rapid and dramatic response to low does steroids
Steroid dose: PMR - start at prednisolone 15mg daily
What is inflammatory myositis?
WEAKNESS of muscle
Idiopathic inflammatory myopathies
Autoimmune
Peak incidence age 40-50 years
Clinical features of inflammatory myositis
Muscle weakness
Insidious onset, worsening over months
Usually symmetrical, proximal muscles
Often specific problems eg difficulty brushing hair, climbing stairs
Myalgia in 25-50% (usually mild)
What is Dermatomyositis?
Clinical features of dermatomyositis?
Investigations for dermatomyositis?
Anti-Mi 2
What are other organs involved in inflammatory myopathies (dermatomyositis & inflammatory myositis)?
What is antisynthetase syndrome?
What is fibromyalgia?
PAIN & FATIGUE
Common cause of chronic musculoskeletal pain
NOT a disease of the muscle
Commonest cause of musculoskeletal pain in women 22-50 years
Prevalence of 2-5%
Commoner in women (F:M, 6:1)
May begin after emotional or physical trauma
What are clinical presentations of fibromyalgia?
How to manage fibromyalgia?
In general, avoid medication –> ineffective and addictive
Patient education
Multi-disciplinary response
Graded exercise programme
Cognitive behavioural therapy
Complementary medicine eg. acupuncture
What is myopathy?
Myopathy is a disease of the muscle in which the muscle fibres do not function properly. This results in muscular weakness
How to investigate inflammatory myositis?
- Blood test
Muscle enzymes eg. creatine kinase (CK)
Inflammatory markers
Electrolytes, calcium, PTH, TSH (to exclude other causes)
Autoantibodies: ANA, Anti-Jo-1, Myositis specific antibodies - Electromyography (EMG):
increased fibrillations, abnormal motor potentials, complex repetitive discharges
How to diagnose inflammatory myositis?
- Muscle biopsy: DEFINITIVE TEST. Perivascular inflammation and muscle necrosis
- MRI: muscle inflammation, oedema, fibrosis and calcification
How to treat inflammatory myositis?
Initial treatment: high dose corticosteroid + immunosuppression medications
eg. Mycophenolate Mofetil
Methotrexate
IV immunoglobulin
Rituximab
What are differential diagnosis of muscle weakness?
Rhabdomyolysis
What is a side effect of simvastatin and how would combined use of diltiazem exacerbate this side effect?
