Muscle Disease Flashcards
name 7 possible causes of myopathy
inflammatory Endocrine disroders Electrolyte disorders metabolis myopathies drugs and toxins infection rhabdomylysis
general presentation of muscle disease?
muscle pain (myalgia)
muscle weakness/tiredness
stiffness
abnormal blood tests
name 2 idiopathic inflammatory myopathies
polymyositis
dermatomyolitis
who gets idiopathic inflammatory myopathy?
more females than men
onset usually 40-50 y/o
does inflammatory myopathy increase cancer risk?
yes
greatest risk in men >45
histological features of inflammatory myopathy (IM)?
muscle fibre necrosis
degeneration
regeneration
inflammatory infiltrate
clinical features of IM?
muscle weakness = main feature incidious onset - worsening over months symmetrical, proximal muscles often specific problems - i.e cant brush hair etc myalgia in 25-50%
what is dermatomyositis?
inflammatory myopathy which affects the skin
Gottrons sign = inflammation on the knuckles
heliotrope rash
shawl sign
what organs can IM affect?
lungs - ILD, resp muscle weakness
oesophagus - dysphagia
cardiac - myocarditis
systemic - fever, weight loss, raynauds, non-erosive polyarthritis
IM history?
muscle symptoms PMH - DM, thyroid DH - steroids, statins FH SH - alcohol/drug use Other - weight loss, cough, breathless, raynauds
how can IM affect muscles?
can cause atrophy and loss of muscle power
2 types of testing for muscle power?
conformational - direct test (push against)
isotonic - 30 secs to stand and sit
how can IM be diagnosed?
History Bloods electromyography muscle biopsy MRI
muscle biopsy features?
perivascular inflammation
muscle necrosis
MRI features?
muscle inflammation
oedema
fibrosis
calcification
blood test features?
CK enzyme
inflammatory markers
Autoantibodies - ANA, anti-Jo-1
electrolytes, calcium, PTH, TSH (to exclude other things)
EMG features?
increased fibrillations
abnormal motor potentials
complex repetitive discharges
how is IM treated?
steroids
azathioprine/methotrexate/ciclosporin?
IV immunoglobulin
Rituximab
what is a heliotrope rash associated with?
dermatomyositis
what is the definitive test for polymyositis?
muscle biopsy
main symptoms in inflammatory myositis?
muscle weakness
what drug might cause a presentation similar to myositis?
statins
who gets polymyalgia rheumatica?
over 50s
associated with giant cell arteritis and temporal arteritis
clinical features of PR?
aching in shoulder and hip morning stiffness usually symmetrical fatigue, weight loss, fever sometimes reduced movement normal muscle strength
how is PR diagnosed?
mainly focused on clinical features and examination
exclude other diagnosis
bloods - raised inflammatory markers
temporal artery biopsy
how is PR treated?
steroids
higher dose if temporal arteritis
gradually reduce dose over 18 months to 2 years
what is fibromyalgia?
non-inflammatory cause of chronic MSK pain
more common in women 22-50
what can trigger fibromyalgia?
physical or emotional trauma
what causes the sensation of pain in fibromyalgia?
central sensitization
fibromyalgia cycle?
emotional and physical pain etc lead to less movement leads to worse symptoms etc
can fibromyalgia affect other systems?
yes
almost all
clinical features of fibromyalgia?
widespread pain diffuse and chronic symptoms worsen with exertion, fatigue and stress sensation of swelling poor sleep pins and needles headaches depression abdo pain (IBS) poor cognition
clinical finding of fibromyalgia?
excessive tenderness on palpation of soft tissues (11/18 points)
no actual abnormality
how is fibromyalgia diagnosed?
clinically
widespread pain with associated symptoms
present 3 or more months
no other explanation
associated symptoms?
bad sleep
cognitive symptoms
fatigue
other somatic symptoms
how is fibromyalgia medically treated?
analgesia (usually not opiates)
anti-depression
gabapentin and pregabalin
non medical fibromyalgia treatment?
education
graded exercise programme
CBT
complementary medicine (e.g acupuncture)
