Muscle Dystrophies and Spinal Muscle Atrophy Flashcards
1
Q
Muscular Dystrophy
A
- Definition: group of hereditary myopathies
- Characteristics:
- Progressive muscle weakness, deterioration, destruction, and regeneration of muscle fibers
- Muscle fibers gradually replaced by fibrous and fatty tissues
- Types
- Beckers dystrophy
- Myotonic dystrophy
- Limb girdle dystrophy
- Facioscapulohumeral dystrophy
2
Q
Congenital/myotonic muscular dystrophy
A
birth
dominant
Typically slow with significant intellectual impairment
3
Q
Duchenne’s Muscular Dystrophy
A
- Incidence
- One of the most prevalent and disabling types of MD
- Between 1/3500 male births
- Prognosis
- Mortality usually due to respiratory or cardiorespiratory insufficiency
- Many are surviving into their 30s
- New challenges for therapy, education, and vocation
4
Q
Etiology Duchenne’s Muscular Dystrophy
A
- Sex linked recessive disorder
- Abnormality on X chromosome at band Xp21
- Results in a disorder of encoding dystrophin and dystrophin associated proteins (DAP)
- Dystrophin acts as an anchor in the intracellular lattice to enhance tensile strength
- If dystrophin is absent from the muscle 🡪 fragility in the muscle membrane during muscle contraction + relative muscle hypoxia as a result of an aberrant vascular response to exercises
- Early breakdown of muscle fiber plasma membrane
5
Q
Duchenne’s Muscular Dystrophy Characteristics
A
- Creatine kinase is elevated early in the disease
- Present at birth long before symptoms are present
- Muscle biopsy shows degeneration with loss of fibers, variation in fiber size, and a proliferation of connective and adipose tissue
6
Q
Duchenne’s Muscular Dystrophy: Clinical Presentation
A
- Insidious onset
- May be misdiagnosed
- Early symptoms
- Reluctance to walk/run at appropriate ages
- Falling
- Difficulty with stairs
- Toe walking
- Clumsiness
- Pseudohypertrophy
- Gastroc
- Deltoids
- Quads
- Forearm extensors
- Proximal muscles weak early on
- Weakness of hip and knee extensors early
- Gower’s sign
- Initial weakness of the neck/trunk flexors, hip extensors, and interscapular muscles
- Intellectual impairment
- Emotional disturbance
- With progression
- Exaggerated lordosis
- Wide BOS
- Waddling gait
- ITB contracture
- Heel cord contracture
- Loss of unassisted ambulation at ages 9-10
7
Q
Duchenne’s Muscular Dystrophy: Medical Intervention
A
- Steroids
- Prolong life by 3 years
- Improve isometric UE strength by 60%
- Improve isometric LE strength by 85%
- Improve pulmonary and cognitive function
- Side effects
- Weight gain
- Growth suppression
- Cataracts
- Osteoporosis
- Other interventions
- Myoblast transplant
- Gene therapy
- Cell based replacement therapy
- Creatine
- Improved muscle strength/endurance
- Less joint stiffness
- Surgical interventions
- Muscle releases (Achilles, fasciotomy of TFL/ITB)
- Scoliosis stabilization
8
Q
Prognostic factors Duchenne’s Muscular Dystrophy
A
- Timed functional activities closely related to muscle strength and predictive of loss of ambulation
- 10M walk/run time greater than 9 seconds predicts loss of ambulation within 2 years
- Inability to rise from the floor predicts loss of ambulation within 2 years
- 10M walk/run time greater than 12 seconds predicts loss of ambulation within a year
9
Q
Duchenne’s Muscular Dystrophy: Evidence Based Tests and Measures
A
- Northstar Ambulatory Assessment
- The Performance of Upper Limb for Duchenne
- Brook Scale
- Vignos Scale
- Egen Klassifikation Scale
10
Q
Vignos Scale
A
1-10 scale with 1 being able to walk and climb stairs without assistance and 10 being confined to bed.
11
Q
Duchenne’s Muscular Dystrophy: PT Role
A
- Early diagnosis
- Education, referral, and support for the family
- Weight control
- Sleep and respiratory concerns
- B&B concerns
- Goals
- Prolong function
- Prevent contractures/deformities
- Adapt equipment
- Encourage peer and community interaction
- Pain control
- Many experience spasms and pain
- Massage and gentle stretching appear to help
12
Q
DMD: Interventions for Infancy-Preschool Age
A
- Characteristics
- May see developmental delay related to weakness
- Mild tightness of the gastroc/TFL
- PT goals
- Family support and education
- Consider daily ROM and night splinting
13
Q
DMD: Interventions for Early School Age Period Characteristics
A
- Characteristics
- Limitations in activity more apparent
- Clumsiness
- Falling
- Difficulty with stairs
- Rising to standing/running
- Gait deviations
- Increased BOS
- Compensated Trendelenburg
- Toe walking
- Lordosis with shoulder retraction
- Lack of arm swing
- Limitations in activity more apparent
14
Q
DMD: Interventions for Early School Age Period
A
- Family support and education
- Obtain baseline data on ROM/MMT
- Strength and exercise
- Widely accepted that eccentric exercise and immobilization are detrimental
- Key muscles: abdominals, hip ext/abd, knee extensors
- Maintain ROM/flexibility
- May not be able to prevent contractures, but can slow development
- Key muscles: gastrocs, HS, and TFL
- 1-2x daily, 10 reps, 30-60 seconds
- Night splints in combination with daily stretching most effective; can prolong ambulation
- Cycling, swimming, and standing for 2-3 hours daily
- Respiratory function
- Measure RR
- Chest wall excursion
- Coughing
- Secretion clearing
- Spirometry
- Breathing exercises
- Inspiratory muscle training
- Monitor progression
- Consider need for other mobility options (MWC, scooters, PWC)
- Risk for falls if ambulation continues past when it is feasible
- Risk for scoliosis increases once the child is nonambulatory
15
Q
DMD: Interventions for Adolescent Period
A
- Impairments
- Considerable deterioration in function
- Loss of walking
- Reliance of powered mobility
- Considerable deterioration in function
