Muscle Disease Flashcards
What are some inflammatory causes of muscle disease
Polymyositis
Dermatomyositis
Inclusion body myositis
Polymyalgia Rheumatica
How do muscle diseases commonly present
Muscle pain (myalgia)
Muscle weakness/ tiredness
Stiffness
Occasionally abnormal bloods,
organ involvement and skin rashes
What is the difference between polymyositis and dermatomyositis
Exactly the same but dermatomyositis also has skin involvement
At what age do polymyositis and dermatomyositis often appear
Between 40 and 50 years
There is an increased malignancy with both polymyositis and dermatomyositis. In one there is a particularly increased risk. What one of these 2 is this
Dermatomyositis
How can we describe polymyositis and dermatomyositis
Idiopathic inflammatory myopathies that appear in a symmetrical pattern
What are some of the clinical features of polymyositis and dermatomyositis
Muscle weakness
Insidious onset, worsening over months
Proximal muscles
What happens to the muscle cells in polymyositis and dermatomyositis
The muscle cells are lost and therefore muscle bulk
What is a key feature of dermatomyositis
Gottrons sign or gottrons papules
Where is there evidence of Gottrons sign
Over the PIP and the metapharyngeal joints
Describe the appearance of the Heliotrope rash that can appear in dermatomyositis
Purple rash around the eyes
Describe the appearance of the Shawl sign that can be appear in dermatomyositis
purple colour rash over the back of the neck or a v shaped rash down the front of the chest
What is the most common organ involved in polymyositis or dermatomyositis
Lung (interstitial lung disease and respiratory muscle weakness
Respiratory muscle weakness can lead to breathlessness
What organs can be involved in polymyositis or dermatomyositis
Oesophageal (dysphagia)
Cardiac (myocarditis)
Other (fever, weight loss, Raynauds phenomenon, non-erosive polyarthritis)
What kind of malignancies can develop from polymyositis or dermatomyositis
Ovarian, breast, stomach, lung, bladder and colon (hollow organs)
Who is the malignancy risk greatest in in patients who have either polymyositis or dermatomyositis
men over the age of 45
What types of drug can cause muscle pain and muscle inflammation
Statins
What other medical conditions are important to know about when taking a history for suspected polymyositis or dermatomyositis
Diabetes mellitus and thyroid disease
On examination of a patient with either polymyositis or dermatomyositis, what can be scene
Wasting of the muscles usually the big proximal ones
What should be tested in examining a patient with polymyositis or dermatomyositis
Confrontational - muscle power
Isotonic testing - 30 seconds sitting to standing test (repeated muscle strength
Why is it useful to do confrontational testing and isotonic testing
It is easy to compare results - to see if medication is helping and how poor they are during a flare etc.
What should be tested in suspected polymyositis or dermatomyositis
Muscle enzymes (CREATINE KINASE CK)
inflammatory markers
electrolytes, calcium, PTH, TSH
Autoantibodies: ANA and Anti-Jo-1
Electromyography (EMG)
- increased fibrillations
- abnormal motor potentials
- complex repetitive discharges
Muscle Biopsy
- definitive test
- perivascular inflammation and muscle necrosis
MRI
-muscle inflammation
-oedema
fibrosis and calcification
Why is CK likely to be high in polymyositis or dermatomyositis
The muscle itself is inflamed which causes the breakdown of the muscle cells which release CK
What are the 5 different types of treatment for polymyositis or dermatomyositis
Glucocorticoids (40mg/day, fast acting) Azathioprine (take 6-8 weeks to work) Methotrexate Ciclosporin IVIG
The steroid treatment for polymyositis or dermatomyositis should gradually be increased. True or False
False - it should be gradually decreased until the patient is only on immunosuppressive therapy
Patients with Inclusion body myositis are often misdiagnosed as having what
Polymyositis
What age group and sex are more likely to develop Inclusion body myositis
over 50s
More common in men
What muscles are typically affected in Inclusion body myositis
Distal muscles - weakness in wrist and finger flexors in upper limbs and quadriceps and anterior tibial muscles in legs
What is the main different between Inclusion body myositis and Polymyositis or dermatomyositis
Inclusion body myositis is assymetrical and Polymyositis or dermatomyositis is symmetrical
What does a muscle biopsy of Inclusion Body Myositis show
Inclusional bodies
Patients with Inclusion Body Myositis tend to have a fairly poor response to treatment. True or False
True
What age of patients are likely to develop Polymyalgia Rheumatica
Those over 50 years
Where is there a higher incidence of Polymyalgia Rheumatica
Northern regions - iceland and scandinavia (near the equator it is rare)
What conditions is Polymyalgia Rheumatica associated with
Temporal arteritis and giant cell arteritis
What muscles does Polymyalgia Rheumatica affect
Proximal muscles
What is the problem with muscle biopsies in Polymyalgia Rheumatica
The muscles look normal as the problem does not arise at the level of the muscle
What are some of the clinical manifestations of Polymyalgia Rheumatica
Ache in shoulder and hip girdle Morning stiffness Symmetrical Fatigue, anorexia, weight loss, fever Reduced movement of shoulders, neck and hips Muscle strength is normal
What is a common presenting complaint in a patient with Polymyalgia Rheumatica
I could not get up in the morning but over the course of the day things improved
If they lift their arms they really struggle but if you do it for them it is normal as the underlying muscle is normal
What is Temporal arteritis / Giant cell arteritis
Granulomatous arteritis of large vessels
What are some of the presenting complaints with Temporal arteritis / Giant cell arteritis
Headache Scalp tenderness Jaw claudication - when chewing Visual loss Tender, enlarged, non-pulsatile temporal arteries
How can we make a diagnosis of Temporal Arteritis
Raised ESR
Plasma viscosity
CRP
Temporal artery biopsy - you may see thickening of the vessel wall
What is the problem with temporal artery biopsies?
They are not reliable due to having skipped lesions - you get patches of normal areas and affected areas
What is the treatment for Polymyalgia Rheumatica
Low dose steroids (15mg) - very rapid and dramatic response to these
Can polymalgia rheumatica be cured
Yes - within 18months to 2 year
What is the commonest cause of chronic MSK pain
Fibromyalgia
Is fibromyalgia associated with inflammation
No
Who is most likely to get fibromyalgia
Women often between 22-50
When might fibromyalgia begin
After emotional or physical trauma
What are some of the factors in the fibromyalgia cycle
Stress, limited activity, fatigue, depression, muscle stiffness, pain, muscle tension
Describe the sleep pattern is a patient with fibromyalgia
Often disturbed and they often wake up and feel as if they haven’t had a good sleep which ultimately causes more pain
What are some regional symptoms and syndromes related to fibromyalgia
Headache IBS Cognitive difficulties (concentrating and remembering things properly) - brain fog Non cardiac chest pain Numbness that moves from area to area Excessive sweating
What are some of the clinical manifestations of fibromyalgia
Pain in neck, shoulders, lower back and chest wall Varies in intensity Symptoms are worse with exertion, fatigue and stress Sensation of swelling Unrefreshing sleep Pins and needles/ tingling Headaches Depression Abdominal pain Poor concentration and memory
Excessive tenderness on palpation of soft tissue (even cap refill)
How can we establish a diagnosis of fibromyalgia
No diagnostic test
inflammatory markers are normal
Absence of other explanation of symptoms
What is the treatment for a patient with fibromyalgia
Patient education MDT Graded exercise programme CBT Complementary medicine - acupuncture Anti-depressants Analgesia Gabapentin and pregabalin AMATRYPTOLINE
