muscular dystrophy

Question 1

muscular dystrophy general etiology

Answer 1

• genetic inheritance

- progressive loss of muscle contractility secondary to myofibril destruction

Question 2

criteria for classification of Muscular dystrophy

Answer 2

• mode of inheritance
• age of onset
• preogression rate
• muscular morphologic changes
• presence of genetic markers

Question 3

Duchenne’s Muscular dystrophy

Answer 3

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

Question 4

Duchenne’s Muscular dystrophy (DMD) treatment

Answer 4

• 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”

Question 5

DMD medical management

Answer 5

• 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

Question 6

DMD clinical manifestation onset at 4-5 years

Answer 6

• 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

Question 7

DMD initial instability at age 5

Answer 7

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

Question 8

DMD instability seen at ages 6-8

Answer 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

Question 9

DMD manifestation seen ages 8-10

Answer 9

• 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

Question 10

DMD manifestation in adolescent perios

Answer 10

• 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

Question 11

vignos functional rating scale for duchenne muscular dystrophy

Answer 11

• 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

Question 12

Role of exercise in children with DMD

Answer 12

• 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

Question 13

intervention considerations for DMD

Answer 13

• -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

Question 14

mobility and spinal alignment for DMD

Answer 14

• 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

Question 15

exercise and custom equipment

Answer 15

• 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

Question 16

transition to adulthood for DMD

Answer 16

• 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

Question 17

Becker Muscular dystrophy BMD

Answer 17

• 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

Question 18

BMD impairments

Answer 18

• 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

Question 19

transition to adulthood BMD

Answer 19

• 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

Question 20

Congenital Muscualr dystrophy

Answer 20

• onset: birth
• inheritance: recessive
• slow but variable; shortened life span
• characterized by congenital hypotonis, delayed motor development and early onset of progressive weakness

Question 21

Spinal muscular atrophy types

Answer 21

• childhood-onset Type I acute
• childhood - onset type II chronic
• juvenile- onset Type III

Question 22

Child hood onset Type I acute

Answer 22

• 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

Question 23

childhood-onset Type II chronic

Answer 23

• 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

Question 24

juvenile- onset Type III

Answer 24

• onset 5-10 years
• inheritance: recessive
• slow progressive; mild impairment

Question 25

SMA diagnosis and pathophysiology

Answer 25

• second most common group of fatal recessive disease
• autosomal recessive with genetic defect on chromosome 5. Survival motor neuron
• abnormality of anterior horn in SC. number of cells reduced, progressive degeneration of remaining contributes to loss of function

Question 26

SMA type I infancy

Answer 26

• weak or absent fetal movement during last month of pregnancy
• significant weakness at birth
• positioning programs are necessary
• respiratory care is central focus
• prone on elbows is not typically attained- use of developmental ther-ex is controversial but appropriate if family agrees and child tolerates
• supported sitting for only short periods to avoid fatigue
• mean age of death 6 mo

Question 27

SMA Type II three sub groups,

-Most severely involved

Answer 27

• children never develop the ability to sit alone and repiratory capacity is severely reduced

Question 28

SMA Type IIthree sub groups

- intermediate group

Answer 28

• child sits along, but never able to walk. forced vital capacity regress to 45% by age 10

Question 29

SMA Type II three sub groups

- least severe

Answer 29

-independent walking attained, 50% then loose this ability by end of first decade

Question 30

SMA Type II infancy

Answer 30

• 15% show impairment within first 3 months
• sitting posture is if primary concern. molded seat or TLSO for support in sitting
• PT kept short to avoid fatigue. emphasize selcetd developmental area

-if child is not standing by 16-18 mo, adaptive equipment should be considered

Question 31

SMA Type II prechool and school age

Answer 31

• toddlers may need KAFOs for standing. progression of weakness may make walking an unrealisticgoal
• initiation of walking program in parallel bars followed by walker use is recommended
• for child whod does not develop independent mobility and when ambulation has ceased, power mobility is necessary. change side of joystick every months to avoid pattern of leaning to one side

Question 32

SMA type II progression to adulthood

Answer 32

• survival into adulthood is extremely variable
• intelligence is rarely affected
• aggressive pulmonary care is required. breathing exercises and postural drainage
• ROM continuation to control progression of contrcatures

Question 33

Juvenile onset SMA Type III

Answer 33

• typical onset later in 1st decade

- may demonstrate some weakness with in first year of life in proximal hip and shoulder girdle

Question 34

juvenile onset SMA type III impairments, functional limitation

Answer 34

• proximal LE weakness MC
• secondary impairments include postural compensation due to muscle weakness, contractures and occasional scoliosis
• increased lumbar lowrdosis, Trendelenburg gait pattern
• and plantar flexor contracture frequent
• incidence of scoliosis and severity related to degree of weakness and fucntiona status