3: Neurology - Muscular dystrophies Flashcards
What are muscular dystrophies
Group of progressive disorders affecting musculoskeletal system
What are the three types of muscular dystrophies
- Duchenne
- Becker’s
- Limb-Girdle
In which gender do muscular dystrophies occur and why
Males
What is the inheritance pattern of muscular dystrophies
X-linked recessive
What causes muscular dystrophy
Mutation in dystrophin gene
What type of mutation is present in duchenne muscular dystrophy
Frameshift
What type of mutation is present in becker’s muscular dystrophy
Point mutation
What age does duchenne muscular dystrophy occur
onsets 2-5 years
Where is weakness in duchenne muscular dystrophy
Proximal muscles
How will gait present in duchenne muscular dystrophy
Waddling
What are two signs seen in duchenne muscular dystrophy
- Calf pseudo hypertrophy
- Gower’s manoeuvre
What is Gower’s manoeuvre
Individual uses their hands to walk themselves up their legs to standing
Why does calf pseudo hypertrophy occur
Replacement calf-muscle with fat
What is an early sign of duchenne muscular dystrophy
Delayed gross motor milestone - difficulty walking
What is duchenne muscular dystrophy associated with
Cognitive impairment
What is main cause of death in duchenne muscular dystrophy
- Respiratory failure
- Dilated cardiomyopathy
What is Becker’s muscular dystrophy
Presents similarly to duchenne muscular dystrophy however onsets after 15-years and is milder
Explain progression in Becker’s muscular dystrophy
Milder and slower progression
What is a more common association with Becker’s muscular dystrophy
Heart defects
What is the role of the dystrophin protein
Holds cytoskeleton to ECM
What happens in muscular dystrophy
Disruption in dystrophin causes muscle-cell necrosis which results in replacement with fat - causing it to appear large = pseudohypertrophy
What is first-line for duchenne muscular dystrophy
Creatinine Kinase (CK)
What is second-line for DMD
Genetic analysis
When may a muscle biopsy be performed
Genetic analysis inconclusive
How will muscle biopsy present in DMD
Absent dystrophin
How will muscle biopsy present in BMD
Reduced dystrophin
How is DMD managed during the early-stages
- Physio
- Orthoses
- Corticosteroids
- Vitamin D and Calcium supplements
What is the advantage of corticosteroids
Prolongs survival
What are individuals given in late-stage to aid with mobility
Electric wheelchair
What respiratory parameters should be monitored in DMD
Vital capacity
What is given to manage respiratory function in DMD
Non-invasive ventilation
What is offered from cardiology for DMD
Screening every 6-months
What may be seen on cardiac screening in DMD
Dilated cardiomyopathy
What is prognosis of DMD
Often survive until 20’s, due to respiratory failure
What are complications of DMD
- Contractures
- Resp Failure
- GI: pseudoobstruction
- Progressive failure resp muscles
