Muscular Dystrophies (Ch. 15) Flashcards
What is muscular dystrophy characterized by?
progressive atrophy = muscle wasting
What is the protein involved in muscular dystrophy and its affect from mutation?
dystrophin = absence due to mutation –> muscle tissue lacks integrity
What are the 2 most common types of muscle dystrophy?
Duchenne MD and Becker’s MD
What is the onset and disease progression of DMD?
early childhood onset, before 3 y/o
rapid progression
Most = wheelchair bound by 12 y/o and die of respiratory failure in early to mid-20s.
More repeats than beckers (CAD)
What is the onset and disease progression of BMD?
later in childhood or adolescence
less severe and slower progression
Death usually occurs in the mid-40s.
What is the pattern of inheritance for all MD?
X-linked recessive
What clinical presentations might DMD carriers (females) have?
cardiomyopathy, muscle weakness
What are some signs and symptoms with MD?
- atrophy
- waddling gait
- pain/stiff muscles
- pseudohypertophy
- difficulty with running/jumping
- scoliosis, spinal fusion
- cardiac problems
- Gower’s sign
What is pseudohypertophy?
replacement of muscle tissue with fat and fibrous tissue; specifically calf muscle
What is Gower’s sign?
proximal muscle weakness; patient needs to “walk up” his legs with his hands to keep an upright posture
What diagnostic tests confirms MD?
- ↑ creatine kinase (CK) levels (damaged muscles produce creatine kinase as byproduct)
- ↑ myoglobin = indicate breakdown of skeletal and cardiac muscles
- Western blot
- biopsy
- EKG
What is myotonic MD?
adult onset MD
What are treatments for MD?
- PT, OT
- corticosteroids
- cardiac medications
- immunopsuppresants
- Gene replacement therapy
What is the clinical presentation of myotonic MD?
- facial and neck muscles = affected first
- cataracts, sleepiness, and arrhythmia
- difficulty relaxing a group of muscles once contracted
What is congenital MD?
- from birth or before 2 y/o
- affects both females and males
