Muscular Dystrophy Flashcards
what is it
skeletal muscle degeneration (progressive)
d/t atrophy, necrosis (of the muscle fibre) & pseudo hypertrophy (inc in size but its false bc of some other tissue (connective tissue) going into the muscle - not inc in muscle inc)
what type is most common
duchenne muscular dystrophy is most common
who is most likely to get it? why? prevalence?
1 in 3500 births (male)
r/t inheritance and mode of transmission
why are there so many different forms?
look at muscle group (which group of sk muscle)
what age is the onset (0-60 yr)
mode of inheritance
progression of disease
how is it inherited?
recessive, x linked trait (sex chromosomes)
-mom is carrier to son. X will go to son but if daughter, she will get the other X and it will override
short arm of the X chromosome (long arm and short arm)
what is dystrophin? fx?
membrane protein found on muscle membrane called sarcolemma.
attaches to contractile filaments and helps with attachment to membrane
patho?
o mutation → alt protein → poor contractile and protein attachment → fibre necrosis with use → poor repair & regen → more necrosis →Ca influx & E release (eg CK)
fibrofatty tissue replaces muscle because body attempt to compensate for the necrosis and non muscle components deposit in there
manifestations?
asymp until 2-3 (injury only happens when you use the muscle)
prog muscle weakness
resp and cardiac muscle affected (difficulty breathing)
usually death from resp and cardiac complications ~around 20
Dx
hx (won’t seek medical attn in first years of life)
voluntary movement
serum CK
biopsy- look at the sample of muscle and section and stain the tissue and see adipose tissue, could see Ca deposits and dystrophin on the sarcolemma
2 other: carrier status of mom before conception and during pregnancy (prenatal testing- 12 wk)
Tx?
no cure (can’t form new muscles)
supportive and symptomatic
inc comfort and fx
-breathing exercises indicated
use the muscles (but more damage)
