Flashcards in Muscular Dystrophy Deck (12):
What are muscular dystrophy disorders?
genetic defects that impair normal muscle fxn
How is DMD inherited?
2/3 are inherited from mother carrying genetic mutation on X chromosome
What is the mutation involved in DMD?
DMD= Xp21 position -> loss of functional expression
BMD= Xp21 -> reduced functional expression
What is the patho in muscular dystrophy?
ongoing degeneration & regeneration of muscle fibers->
progressive breakdown of affected muscle
(starts as muscle hypertrophy, after years has atrophy)
What are clinical manifestation of DMD?
-growth delay in 1st year of life
-clinical onset of weakness begins 2-3 years old
-lower extremities before upper
What is Gower's sign, DMD?
using hand to support when arising from the ground (because legs are affected before upper extremities)
How is respiratory fxn affected in DMD? What is needed?
gradual weakening of respiratory muscles
ventilator support by 25 years old
How is the cardiac sx involved in DMD?
-primary dilated cardiomyopathy
How does BMD compare to DMD?
-growth delay is uncommon
-cognitive impairment is uncommon
-muscle involvement later in life (common to retain strength, contracture are less common)
-Cardiac involvement MORE predominant
-Less respiratory involvement
What unexplained labs might you see in a pt w/ muscular dystrophy?
AST and ALT
Dx studies for muscular dystrophy
-Serum creatine kinase
(DMD 50-100x nl, BMD 5x nl)
-genetic testing for Xp21 mutation