Muscle Disease Flashcards
what are causes of muscle disease
inflammatory endocrine metabolic myopathies electrolytes disorders infection drugs and toxins rhabdomyolysis fibromyalgia
what is Polymyositis and Dermatomyositis
idiopathic inflammatory myopathies
which one is more linked with malignancy between Polymyositis and Dermatomyositis
dermatomyositis
what are the clinical features of Polymyositis and Dermatomyositis
Muscle weakness - most common presenting feature
Insidious onset - worsening over months
Symmetrical, proximal muscles
Mild myalgia (muscle pain) in some
what do people with Polymyositis and Dermatomyositis often present with
specific problems with muscle weakness
difficulty brushing hair, climbing stairs
how are Polymyositis and Dermatomyositis different
dermatomyositis has cutaneous features
what are cutaneous features of Dermatomyositis
Gottrons sign - red-purple areas over PIP and MCP joints
Heliotrope rash - purple-red rash around the eyes
Shawl sign - rash around shoulders and in v shape down the chest
what can be other organ manifestations in Polymyositis and Dermatomyositis
Lung:
Interstitial lung disease
Respiratory muscle weakness
Oesophageal:
Dysphagia
Cardiac:
Myocarditis
Other:
Fever, weight loss, Raynauds phenomenon, non-erosive polyarthritis
what cancers are linked with Polymyositis and Dermatomyositis
ovarian, breast, stomach, lung, bladder and colon
what can be features of the history that can make you suspect Polymyositis and Dermatomyositis
PC - tired muscle, functional difficulty, muscle pain
PMH - DM, thyroid disease
Dx - steroids, statins
Sx - alcohol, cocaine
Systemic - Weight loss, cough, SOB, Raynauds
what might be seen on examination of Polymyositis and Dermatomyositis
loss of muscle bulk
muscle wasting
what tests can be done for Polymyositis and Dermatomyositis
confrontation testing - direct testing of power
isotonic testing - 30 second sit to stand test
what investigations can be done for Polymyositis and Dermatomyositis
Serum CK levels - will be elevated
Inflammatory markers
EMG - electromyography
Muscle biopsy - the definitive test for diagnosis
what autoantibodies are associated with Polymyositis and Dermatomyositis
ANA
Anti-Jo-1
what would be seen in a muscle biopsy of Polymyositis and Dermatomyositis
Perivascular inflammation and muscle necrosis
treatment of Polymyositis and Dermatomyositis
1 - Oral steroids; 40mg daily Prednisolone
2 - Immunosuppression; Methotrexate, Azathioprine or Ciclosporin
3 - IV immunoglobulin; used in people who have failed standard therapy
how does inclusion body myositis (IBD) differ from polymyositis and Dermatomyositis
weakness often ASYMMETRICAL commoner in men diagnosed at much older age> 50 more insidious onset distal muscle weakness - tends to start with lower legs and hands
what muscles are commonly affected in IBD
wrist and finger flexors in upper limbs
quadriceps and anterior tibial muscles in legs
Ix of IBD
CK levels - lower than in PM ad DM
Muscle biopsy - inclusion bodies seen
treatment of IBD
responds very poorly to treatment
who gets Polymyalgia Rheumatica (PMR) and what is it associated with
> 50 years old
Temporal arteritis/Giant cell arteritis
features of PMR
NO MUSCLE WEAKNESS ache in shoulder and hip girdle morning stiffness and pain symmetrical Fatigue, anorexia, weight loss, fever
what are the findings of clinical examination in PMR
reduced movements of shoulders, neck and hips
muscle strength is NORMAL
symptoms/signs of Temporal arteritis/Giant cell arteritis
headache scalp tenderness jaw claudication visual loss (amaurosis fugax) tender, enlarged, non-pulsatile temporal arteries
