Polymyositis Flashcards
Polymyositis is an autoimmune mediated connective tissue disease that causes inflammatory disease that causes muscle weakness. What is the incidence of polymyositis?
1 - 1 : 100
2 - 1 : 1000
3 - 1 : 10,000
4 - 1 : 100,000
4 - 1 : 100,000
Polymyositis is an autoimmune mediated connective tissue disease that causes inflammatory disease that causes muscle weakness. Does it affect men or women more?
- women
Polymyositis is an autoimmune mediated connective tissue disease that causes inflammatory disease that causes muscle weakness. What age is the peak incidence?
1 - 20-30 years
2 - 30-40 years
3 - 40-50 years
4 - 50-60 years
4 - 50-60 years
Although the exact cause of polymyositis is unknown, it is though that it is caused by an abnormal immune response. normally do host cells present MHC-1 or MHC-II to cytotoxic T cells?
- MHC-1
- check is the antigen presented on the MHC-1 is a self antigen
- however, if the cell is infected or damaged the cytotoxic T cell will induce cell apoptosis
In polymyositis, it has been suggested that cytotoxic T cells bind to MHC-1 on skeletal muscle, but react as though the antigen is foreign. What is the term used when host antigens resemble foreign antigens?
1 - mirroring
2 - molecular mimicry
3 - cross reactivity
4 - molecular camouflage
2 - molecular mimicry
When T cells react to host antigens, this is called autoantigens
If a CD8 (cytotoxic) T cell binds to a host antigen on skeletal muscle cells but recognises it as foreign then the T cell will induce apoptosis. Which other cell can also begin producing antibodies against the skeletal muscle?
1 - CD4 T helper cells
2 - neutrophils
3 - macrophages
4 - B cells
4 - B cells
B cells can produce antibodies that target skeletal muscle in polymyositis. Which antibodies are produced that are specific to polymyositis?
1 - anti-Ro
2 - anti-La
3 - anti-tRNA synthetases (Jo-1)
4 - anti-Mi-2 nuclear protein (Mi-2)
3 - anti-tRNA synthetases (Jo-1)
4 - anti-Mi-2 nuclear protein (Mi-2)
- this is typically how patients are diagnosed
- muscle biopsy can also be used
Once skeletal muscles begin being damaged by cytotoxic T cells, there is inflammation in the surrounding tissues. The damage muscle also leak which enzymes into the blood that can be measured and help with diagnosis?
1 - creatine kinase,
2 - aldolase
3 - lactate dehydrogenase
4 - all of the above
4 - all of the above
All of the following are common presenting clinical features of polymyositis. Which of the following is the most common feature?
1 - muscle weakness
2 - muscle tenderness
3 - raynaud’s
4 - respiratory muscle weakness
5 - interstitial lung disease
6 - dysphagia
7 - dysphonia (vocal changes)
1 - muscle weakness
- this is often bilateral
Progressive muscle weakness and pain are common clinical features of polymyositis. Which 2 of the following are most commonly affected?
1 - shoulder muscles
2 - pelvic girdle muscles
3 - arm muscles
4 - leg muscles
1 - shoulder muscles
2 - pelvic girdle muscles
- flexors of the neck may also be affected
Which of the following can be used to diagnose polymyositis in the muscles?
1 - grip strength
2 - sit to stand
3 - electromyography
4 - MRI
3 - electromyography
- able to identify dead or weak muscles
Once diagnosed, what is the 1st line treatment for polymyositis?
1 - Corticosteroids
2 - Immunosuppressives
3 - Intravenous Immunoglobulins (IVIG)
4 - Muscle stimulation
1 - Corticosteroids
- prednisolone is 1st choice
- aim is to suppress the immune response
Once diagnosed, the 1st line treatment for polymyositis is corticosteroids. If this fails immunosuppressives can be tried. Which of the following is NOT an immunosuppressive?
1 - Methotrexate
2 - Anastrozole
3 - Azathioprine
4 - Cyclophoshamide
2 - Anastrozole
- hormone medication
