orthopedic pathology (muscle pathologies) Flashcards
atrophy
decrease in size (cells/muscle)
hypertrophy
increase in size (cells/muscle)
hyperplasia
Increase in number of muscle fibers
Does not occur under normal conditions
contracture
A contracture is the shortening of tissues surrounding a joint, leading to decreased range of motion
includes muscles, but also other tissues such as tendons or ligaments
contractures causes
burns, scars, disuse, many pathologies (cerebral palsy, muscular dystrophy, etc)
Ischemic Necrosis
Some texts say muscles will undergo necrosis after 6 hours
(some texts say 3 hours)
muscular dystrophy
largest and most common group of inherited progressive neuromuscular disorders
how many types MD
more than 30 genetic diseases
MD characterized by
progressive weakness and degeneration of skeletal muscles
Most common form of MD
Most severe form of MD
Duchenne’s MD
differ in types of
type of inheritance, area affected, age at onset, and rate of progression/prognosis
Duchenne’s MD rate
1/3500 male births
Duchenne’s MD – lack in which muscle protein
dystrophin
dystrophin function
Protein that helps muscle fibers maintain their shape/strength
“helps link thin filaments to the sarcolemma for stability”
Duchenne’s MD etiology
Etiology - Genetic (x-linked recessive)
x linked recessive inheritance
X-linked recessive inheritance refers to genetic conditions associated with mutations in genes on the X chromosome.
A male carrying such a mutation will be affected, because he carries only one X chromosome.
A female carrying a mutation in one gene, with a normal gene on the other X chromosome, is generally unaffected.
when symptoms appear?
at 2 - 4 years of age
when loss of unassistec ambulation
Loss of ambulation occurs between 7 – 13 years of age
respirator?
“Night ventilation by body respirators for patients in chronic respiratory failure due to late stage Duchenne muscular dystrophy”
Duchenne’s MD respiratory system
eventually resulting in loss of ambulation, loss of respiratory muscle strength, and death from respiratory insufficiency.
The majority of patients develop cardiomyopathy.
Duchenne’s MD life expectancy
Life expectancy is 20 – 30 years of age
Usually die due to cardiopulmonary issues
Duchenne’s MD initially affects (which part of body)
Initially affects the girdles (shoulders and hips)
SSx
Muscle weakness
Lack of coordination
Spastic movements
Weight loss
Contractures, loss of ROM, deformities – painful
where is there pseudohypertrophy in Duchenne’s MD?
calves
fat storage, not muscle (?)