muscular dystrophy Flashcards
muscular dystrophy general etiology
- genetic inheritance
- progressive loss of muscle contractility secondary to myofibril destruction
criteria for classification of Muscular dystrophy
- mode of inheritance
- age of onset
- preogression rate
- muscular morphologic changes
- presence of genetic markers
Duchenne’s Muscular dystrophy
Onset: 1-4 years
- Inheritance X-linked
- Rapid progressive ; loss of walking by 9-10 years; death in late teens or early twenties
-abnormal/ missing dystrophin. acts as an anchor in the intracellular lattice to enhance tensile strength
Duchenne’s Muscular dystrophy (DMD) treatment
- myoblast transfer therapy. injectionof skeletal muscle precursors from donor into the muscle of an individual with MD
- gene replacement therapy. introduction of dystrophin gene placed in a “vector”
DMD medical management
- Long term steroid use. shown to improve outcomes- prolonged independent and assisted walking by up to 3 years. imporved pulmonary function
- side effect. wt gain, growth suppression and osteoporosis
- use of orthotics and surgical intervention to prolong ambulation is controversial
DMD clinical manifestation onset at 4-5 years
- muscle weakness. neck flexors, abs, hip ex interscapular
- posterior calf enlargement
- ROM WNL prior to age 5
- lordodic standing posture is increased
- scapular winging
- scoliosis before or during adolescence
DMD initial instability at age 5
Mean dx at age 5
- clumsiness, falling, inability to keep up with peers
- gait I smildly atypical
- unable to run or jump
- Grower’s sign
DMD instability seen at ages 6-8
- stair negotiation and standing from floor become more difficult
- gait pattern : increased BOS, compensated Trendelenburg, pronounced lateral sway, shoulder retraction, reduced arm swing
- tow walking: initially compensation for weakness in abdominals ad hip extensors. resulting in lordosis and forward shift of center of mass
DMD manifestation seen ages 8-10
- tow walking due to contracture of posterior calf musculature
- in-toeing with TFL to compensate for weak iliopsoas
- falls secondary to progressive weakness
- complaints of fatigue during ambulation
- progressive decline in pulmonary function. decline in max Vital capacity
DMD manifestation in adolescent perios
- walking lost for mobility ~10-12 yrs
- general mobility for transfers become increasingly difficult
- manual WC or powered mobility is a necessity
- difficulty with ADLs
- manual stretching may be discontinued
vignos functional rating scale for duchenne muscular dystrophy
- 1 lowest - 10 highest
- 1.walks and climb stairs w/o assistance
- walks and climbs stairs with aid of railing
- walks and climbs stairs slwly with aid or railing >25sec
- walks but cannot climb stairs
- walks assisted, but cannot climb stairs or get out of chair
- walks only with assistance or with braces
- in wheelchair: sits erect and can roll chair and perform ADLs
- in wheelchair: sits erect is unable to perform bed and Wheel chair ADLs w/o assistance
- in wheelchair: sits erect only with support and is able to do only minimal ADLs
- in bed: can’t do ADL w/o assistance
Role of exercise in children with DMD
- controversial
- overexertion and immobilization are detrimental
- submaximal ther ex has been shown to be beneficial
- key muscle groups (if ther ex is initiated early) abdominals, hip extensors, abductors, knee extensors
- cycling and swimming are excellent for overall conditioning
- standing and walking for a minimum of 2-3 hours/day is highly recommended
intervention considerations for DMD
- -breathing ex
- ROM and positioning to slow progression of contrcatures. 30-60 sec holds
- prone positioning to sleep to slow hip and knee flexion contractures
- advice modification to PE programs as needed
- routine scoliosis check
- addressing falls and fatigue
mobility and spinal alignment for DMD
- power scooter may be used for a transition to power chair
- manual chair may be required in areas not accessible to power mobility
- monitor WC fit paying close attention to alignment of spine and pelvis
- neutral or slight extension of spinal position to lessen progression of scoliosis
exercise and custom equipment
- shifting emphasis of exercise program from LE to UE
- ROM programs- include stretching of shoulder and elbow
- van lift or ramp
- modification of home. wheeled commode, bath chair, hand held shower, urinal. bed modifications due to inability to change position
transition to adulthood for DMD
- greater reliance on assistive technology for environmental access and ADLs
- social considerations
- environmental control unit on power chair to independently access lights, phone, TV, motor on doors, computers
- breathing ex, postural drainage, or intermittent pressure breathing treatments
Becker Muscular dystrophy BMD
- onset 5-10 years
- inheritance x-linked
- more slowly progressive variant of DMD. maintain walking past early teens; life span into third decade
- *frequently report muscle cramping
- dystrophin is present in reduced amts or abnormal size
- initials clinical sx typically not identified before late childhood or early adolescence
BMD impairments
- same as DMD, less severe
- initial clinical signs: frequent fall and clumsiness in mid to late teens
- cardiac involvement greater than DMD
- contractures in hip knee and ankle plantar flexor muscle may be present when walking is no longer possible
transition to adulthood BMD
- longevity commonly into mid 40s. complications from dilated cardiac myopathy is limiting factor for longevity
- vocational and avocational choices must be made with disease progression and disability level in mind
- govt support may be needed to off set expense for independent living
Congenital Muscualr dystrophy
- onset: birth
- inheritance: recessive
- slow but variable; shortened life span
- characterized by congenital hypotonis, delayed motor development and early onset of progressive weakness
Spinal muscular atrophy types
- childhood-onset Type I acute
- childhood - onset type II chronic
- juvenile- onset Type III
Child hood onset Type I acute
- 0-3 mo
- inheritance: recessive
- rapid progressive; severe hypotonia; death within first year
- Primary impairment is mucle weakness secondary to progressive loss of anterior horn cells
- contrcatures
- inconsistent cranial nerve involvement
childhood-onset Type II chronic
- 3 mo-4 years
- inheritance: recessive
- rapid progressive that stabilizes; moderate to severe hypotonia; shortened life span
- significant weakness appears in first year of life
- three sub groups.
- primary proximal muscle weakness
juvenile- onset Type III
- onset 5-10 years
- inheritance: recessive
- slow progressive; mild impairment