Muscle Disease Flashcards
What is the cause of polymyositis and dermatomyositis?
None- they are idiopathic
Which sex is polymyositis/dermatomyositis more common in?
Females
What is the peak age incidence for polymyositis/dermatomyositis?
40-50
Do polymyositis/dermatomyositis have an increased risk of malignancy?
Yes
What is the difference between polymyositis/dermatomyositis?
They are the same, with the exception that dermatomyositis involves the skin
What is important to know about dermatomyositis in males over 50?
It is often paraneoplastic- these patients should be screened for malignancy
Muscle fibre necrosis, degeneration, regeneration and inflammatory cell infiltrate on histology suggests what?
polymyositis/dermatomyositis
How does the muscle weakness come on in polymyositis/dermatomyositis?
Insidiously, worsening over months
Where is the weakness usually found in polymyositis/dermatomyositis? Is it symmetrical?
Usually in proximal muscles (hip and shoulder girdle) and is usually symmetrical
What is the main clinical feature of polymyositis/dermatomyositis?
Muscle WEAKNESS
What is Gottron’s sign? What disease is it associated with?
Dermatomyositis- papules over the joints in the hands
What disease will show a heliotropic rash around the eyes?
Dermatomyositis
What other organs can be involved in polymyositis/dermatomyositis?
Lungs, oesophagus, heart
What is the lung involvement in polymyositis/dermatomyositis?
Interstitial lung disease/pulmonary fibrosis
What is the oesophageal involvement in polymyositis/dermatomyositis?
Dysphagia
What is the cardiac involvement in polymyositis/dermatomyositis?
Myocarditis
What are 4 systemic features of polymyositis/dermatomyositis?
Raynaud’s, weight loss, fever, polyarthritis
Which out of polymyositis/dermatomyositis has a higher risk of malignancy?
Dermatomyositis
What PMH might be important when suspicious of polymyositis/dermatomyositis?
Diabetes, thyroid disease
What drug use might be important when suspicious of polymyositis/dermatomyositis?
Steroids, statins
What is the sit to stand test (isotonic testing)?
How many times can a person sit to stand in 30 seconds
What blood tests would be useful for polymyositis/dermatomyositis?
Creatinine kinase, inflammatory markers, electrolytes, calcium, PTH, TSH
When is creatinine kinase released?
When muscles start to breakdown
Which autoantibodies may be found in polymyositis/dermatomyositis? Which one is SPECIFIC?
ANA
Anti-Jo-1 (SPECIFIC)
What test can check muscle inflammation?
Electromyography
What is the definitive test (gold standard) for polymyositis/dermatomyositis?
Muscle biopsy
Do polymyositis/dermatomyositis have the same patterns on muscle biopsy?
No
Could you use an MRI for polymyositis/dermatomyositis?
Yes
How do you treat polymyositis/dermatomyositis initially?
High dose steroids to suppress initial inflammation then lower dose while starting a DMARD
What should be used to treat polymyositis/dermatomyositis in patients who don’t respond to DMARDs?
IV immunoglobulin and rituximab
What is a condition that can be misdiagnosed as polymyositis?
Inclusion body myositis
What age group and sex is inclusion body myositis most common in?
> 50 years, more commonly men
Which muscles does inclusion body myositis usually affect?
Distal ones
Is the weakness in inclusion body myositis symmetrical?
No, it is usually asymmetrical
Is inclusion body myositis an autoimmune condition?
No
Will CK levels be raised in inclusion body myositis?
Yes, but not as much as in polymyositis
What does muscle biopsy show in inclusion body myositis?
Inclusion bodies
Does inclusion body myositis respond to treatment?
No
What are the 3 main inflammatory muscle conditions?
- Polymyositis
- Dermatomyositis
- Inclusion body myositis
What age and location is polymyalgia rheumatica associated with?
- Over 50s
- Northern countries
What other medical condition is polymyalgia rheumatica associated with?
Temporal/giant cell arteritis
What is the main clinical feature of polymyalgia rheumatica?
PAIN AND STIFFNESS
Where usually is the ache found in polymyalgia rheumatica? Is it symmetrical?
Usually the hip and shoulder girdle, normally symmetrical
When does the stiffness from polymyalgia rheumatica occur and how long does it last?
In the morning, can last a few hours and then get better
What symptoms as well as the muscle problems can occur in polymyalgia rheumatica?
Fatigue, anorexia, weight loss, fever
Is there a specific test for polymyalgia rheumatica?
No
How long does polymyalgia rheumatica last?
18 months- 2 years
What is the best medication for polymyalgia rheumatica?
Steroids (rapid and dramatic response)
Is polymyalgia rheumatica inflammatory?
Yes
What is the normal starting dose of steroids in any condition?
15mg/day
When should 40mg/day of prednisolone be given in polymyalgia rheumatica?
If there is giant cell arteritis causing headache only
What dose of steroids should be given to a polymyalgia rheumatica patient with giant cell arteritis causing visual disturbances?
60mg/day prednisolone
Is fibromyalgia an inflammatory condition?
No
Fibromyalgia is a chronic cause of pain, usually occurring in who?
Women under 50
What factors may trigger the beginning of fibromyalgia?
Emotional or physical trauma, poor sleep pattern
What is the main clinical feature of fibromyalgia?
PAIN
Does exercise make pain better or worse in fibromyalgia?
Worse
Is there a diagnostic test for fibromyalgia?
No
Is medication useful for fibromyalgia? What could you give patients?
Not really, only give analgesics (amitryptilline, gabapentin)