Muscle disease Flashcards
How do muscle diseases present?
Muscle pain (myalgia) Muscle weakness/tiredness Stiffness Abnormal blood tests Other features
Name two idiopathic inflammatory myopathies?
Polymyosititis-muscle
Dermatomyosistits -muscle and skin
Twice as common in females
peak incidence 40-50 y
Association with malignancy
How does muscle weakness usually occur ininflammatory myopathies?
most common presenting
Worseing over months
Usually symmetrical, proximal muscles
in dermatomyosititis?
Cutaneous disease -Grottons sign
which is a purply violet colour
over MCP and PIP joints
Helitrope rash- eyes
Shawl sign-over the back
on histology what does inflammatory myopathies show?
MUSCLE FIBRE NECROSIS, DEGENERATION, REGENERATION AND AN INFLAMMATORY CELL INFILTRATE
What could be the other organ involvement in inflammatory myopathies?
Lung- ILD,respiratory muscle weakness
Oesophageal-Dysphagia
Cardiac-Myocarditis
Other-Fever, wt loss, raynauds phenomenon, non-erosive polyarthiritis
In inflammatory myopathies who has the greatest risk of malignancy?
men over 45
What is important in terms of the history when diagnosing
Presenting symp- tired muscles, functional difficulty, muscle pain
Other medical problems-DM,thryoid disease
Drugs-steroids,statins
FH
Social-alcohol, illicit drug use
Other symptoms- wt loss, cough, breathlessness,Raynauds
What examination can be used?
Conformational testing - direct testing of power
Isotonic testing- 30 s stand to sit test
WHAT TESTS CAN HELP IN DIAGNSIS
Blood tests- muscle enzymes e.g. CK, Inflammatory markers, Electrolytes, calcium, pTH,TSH(to exclude other causes), autoantibodies( ANA,Anti-Jo)
EMG-increased fibrillations, abnormal motor potentials,comlex repetitive discharges
Muscle biopsy- definitive test (perivascular inflammation and muscle necrosis)
MRI-muscle inflammation, oedema,fibrosis and calcification
What is the treatment?
Glucocorticoids Azathioprine Methotrexate Cislosporin IV immunoglobulin Rituximab
What is inclusion body myosititis?
can be misdiagnosed as polymosititis Patients >50 years commoner in men more insidious onset distal muscle weakness weakness wrist and finger flexors in upper limbs and quadriceps and anterior tibial muscles in legs weakness often asymmetrical CK levels lower the PM Muscle biopsy shows inclusion bodies Responds poorly to therapy
WHAT MEDICATION CAN CAUSE A PRESENTATION SIMILAR TO MYOSITITIS
ATORVASTATIN
Polymyalgia rheumatica
ONLY if over 50
Association with temporal arteritis/giant cell arteritis
ache in shoulder and hip griddle
morning STIFFNESS- reduced movement of shoulders, neck and hips
usually symmetrical
fatigue, anorexia,wt loss and fever may occur
Muscle strength is normal
What symptoms may people get with temporal arteritis/giant cell arteritis?
Granulomatous arteritis of large vessels headaches scalp tenderness jaw claudication visual loss (amaurosis fugal) Tender, enlarged, non-pulsate temporal arteries
