Muscle Diseases Flashcards
Talk about polymyositis ( def + common age )
1- autoimmune disease
2-it presents with bilateral proximal weakness of muscles
3- common in adults
Microscopic picture of polymyostitis
Endomysial lymphocytic inflammation ( mostly cytotoxic c 8 ) and skeletal muscle fibre degeneration and regeneration
Treatment of polymyositis
Patients respond to immunosuppressants
Def of dermatomyositis and common age
Autoimmune disease involving inflammation of skeletal muscles and skin
It presents with bilateral proximal weakness of muscle and skin rash on eyelides and periorbital oedema
Common in children and adults
Def of duchenne muscular dystrophy
X linked disease leads to rapid progression of muscle degeneration
It is more common and severe form of musclar dystrophy
The affected gene is dystrophin gene on chromosome X and mutation in this gene leads to virtual abscence of this protein
The affected boys are normal at birth but onset of symptoms appears at age of 5
Importance of dystrophin protein
Muscle structural protein that protect the muscle from injuries of contractions and relaxation
Clinical features of duchenne musclar dystrophy
1- progressive muscle weakness
2- calf pseudo hypertrophy
3- proximal weakness of shoulders
4- HF AND arrhythmia
5- respiratory insufficiency and infection
6- elevated serum CPK
7- immunostains shows decreased dystrophin protein
8- muscle biopsy shows muscle fibers of variable sizes necrosis and fibrosis and degeneration and fatty infiltration
9- the diagnosis can be confirmed by genetic testing
Talk about becker muscular dystrophy
1- X LINKED disease leads to slowly progressive muscle weakness of legs and pelvis
2- less sevre than duchenne
3- not as common as duchenne
4- later onset than duchenne with variable progression
5- mutation produces an altered dystrophin protein
6- cardiac involvements are rare , patients can relatively live a normal life span
