Muscle Disease Flashcards
How do muscle diseases present?
Muscle pain (myalgia) Muscle weakness/ tiredness Stiffness Abnormal blood tests Other features
Who is likely to get polymositis and dermatomyositis?
Prevalence is 1/100,000
Female to male ratio is 2:1
Peak incidence is 40-50s
What will polymyositis look like histologically?
Muscle fibre necrosis, degenration and regeneration
Inflammataory cell infiltrate
What are the clinical features of polymyositis/ dermatomyositis?
Muscle weakness- insidious onset, worsening over months, usually symmetrical and affects proximal muscles
Will have specific problems e.g. brushing hair, climbing stairs
What cutaneous signs are associated with dermatomyositis?
Gottrons sign
Helitrope rash
Shawl sign
How can polymyositis/ dermatomyositis affect the lungs?
ILD
Resp muscle weakness
How can polymyositis/ dermatomyositis affect the oesophagus?
Dysphagia
How can polymyositis/ dermatomyositis affect the heart?
Myocarditis
What other systemic conditions can polymyositis/ dermatomyositis cause?
Fever
Weight loss
Raynauds phenomenon
Non-erosive polyarthrtitis
What is the link between polymyositis/ dermatomyositis and malignancy?
15% incidence in dermatomyositis, 9% in polymyositis
What malignancies will polymyositis/ dermatomyositis cause?
Ovarian Breast Stomach Lung Bladder Colon cancer
Who is at the highest risk of polymyositis/ dermatomyositis related malignancy?
Men over 65 years
How can a diagnosis of polymyositis/ dermatomyositis be determined from the history?
PS: tired muscles, functional difficulty, muscle pain
PMX: DM, thyroid disease
Drugs: steroids, statins
Social: alcohol, illicit drug use
Systemic Enquiry: WL, cough, SOB, rayanauds
What tests can be performed in an examination of polymyositis/ dermatomyositis?
Confrontational testing - direct testing of power
Isotonic testing - 30 second sit to stand test
What blood tests should be taken in the diagnosis of polymyositis/ dermatomyositis?
Muscle enzymes - CK
Inflammatory markers
Electrolytes, calcium, PTH, TSH
Autoantibodies: ANA, Anti-Jo-1
What will an electromyography show in polymyositis/ dermatomyositis?
Increased fibrilations, abnormal motor potentials, complex repetitive discharges
What will muscle biopsy show in polymyositis/ dermatomyositis?
Perivascular inflammation
Muscle necrosis
What will an MRI show in polymyositis/ dermatomyositis?
Muscle inflammation
Oedema
Fibrosis
Calcification
How is polymyositis/ dermatomyositis treated?
Glucocorticoids Azathioprine Methotrexate Ciclosporin IV immunoglobulin Rituximab
Who will polymyalgia rheumatica affect?
Those over 50
Higher in northern regions
What vasculitis disease is PR associated with?
Temoral arteritis
What are the clinical manifestations of PR?
Ache in shoulder and hip girldle Morning stiffness Symmetrical Fatigue, anorexia, weight loss, fever Reduced movement NORMAL muslce strength
How is PR diagnosed?
Exclude other diagnosis
Raised ESR, PV and CRP
Temporal artery biopsy
How is PR treated?
Rapid and dramatic response to low dose steroids
If GCA present, higher steroid dose needed
What is fibromyalgia?
Chronic msk pain that is not associated with inflammation
Who is likely to be affected by fibromyalgia?
Commonest cause of msk pain in women 22-50
Commoner in women (6:1)
Can begin after emotional or physical trauma
What are the clinical manifestations of fibromyalgia?
Pain in neck, shoulders, lower back and chest wall
Worse with exertion, fatigue and stress
Sensation of swelling
Fatigue and poor sleep
What other extra-articular conditions is fibromyalgia associated with?
Pins and needles Headaches Depression IBS Poor concentration and memory
What are the clinical findings of fibromyalgia on examination?
Excessive tenderness on palpation of soft tissues
11/18 tender points
What is the criterea for diagnosis of fibromyalgia?
Widespread pain with associated symtoms (unrefreshed sleep, cognitive symptoms, fatigue)
Symptoms present for more than 3months
No other condition explains pain - disease of exclusion
How is fibroyalgia treated?
Patient education MDT response CBT Acupuncture Atypical analgesics - anti-depressants, gabapentin and pregabalin
