Muscular Dystrophy

Question 1

What would an EMG of a child with MD reveal?

Answer 1

Progressive loss of muscle contractility as the

myofibrils are destroyed due to a missing protein (dystrophin)

Question 2

How does one diagnose MD?

Answer 2

• Clinical examination
• EMG
• Muscle biopsy
• DNA analysis
• Enzyme levels from blood samples

Question 3

What is the most common type of MD?

Answer 3

Duchenne’s MD

3/100,000 prevalence
1/3,500 male birth incidence

Question 4

Duchenne’s MD stats

Answer 4

• Prevalence 3 per 100,000
• Incidence 1 in 3500 male births
• Life expectancy is late teens to twenties
• Cause of death is often respiratory or cardiac in origin

Question 5

Why is it so uncommon for girls to have MD?

Answer 5

Diseases inherited in an X-linked recessive pattern mostly affect males, because a second X chromosome usually protects females from showing symptoms. In very rare instances, a female could have two faulty x chromosomes, where the female would most likely exhibit mild MD symptoms.

Question 6

What is the primary impairment of MD?

Answer 6

Muscle weakness

Initial weakness usually involves:

– Neck flexors, abdominals, interscapular and hip extensors

– Quad weakness occurs shortly after

Question 7

What is pseudohypertrophy?

Answer 7

Pseudohypertrophy (result of fatty and connective tissue infiltration) is a common symptom

– Pseudohypertrophy can give a
false impression of strength
– Calf is most always pseudohypertrophic
– Other areas sometimes affected include:
• deltoid, quadriceps and forearm
extensors

Question 8

In combination with weakness and
declining activity, this impairment
severely impacts on function

Answer 8

Flexibility

Question 9

No limitations in ROM are noted prior to

____ years of age according to book

Answer 9

5

But Bill disagrees

Question 10

What is the order of ROM loss in MD?

Answer 10

• Initially, tightness is seen in the gastrocsoleus
and TFL
• This is followed by hip flexor tightness
• Knee flexor tightness
• Elbow flexor tightness
• Shoulder extensor/adductor tightness
• Finger/wrist flexor tightness
• Hip adductor tightness as child becomes non-ambulatory

Question 11

_____________ and __________ are common and contribute
significantly to the respiratory
problems children with MD have
later in the disease

Answer 11

Scoliosis and contractures

Question 12

Tightness and weakness contribute to a clinical picture of increased _________ and ____________ in children with MD

Answer 12

Lumbar lordosis and scapula winging

Question 13

In children with MD, cognitive impairments are ________

Answer 13

Unusual

Question 14

True or false: No significant signs of MD disability is usually noted in toddlers

Answer 14

True

Question 15

Half of children with MD are delayed in walking until _______

Answer 15

18 months

Question 16

Symptoms for MD are often not noticed until…

Answer 16

3-5 years

Question 17

The mean age of diagnosis for MD is…

Answer 17

5 years

Question 18

The initial signs of MD

Answer 18

• Clumsiness, falling
• Bilateral trendelenberg gait
• Increased BOS
• Decreased or loss of ability to run or jump
• Gower sign

Question 19

What is the progression of symptoms of MD? (Not muscular order, symptoms in general)

Answer 19

• Difficulty up and down stairs
• Further increased BOS
• More pronounced trendelenberg
• Toe walking
• Decreased arm swing

Question 20

4 things to keep in mind for interventions with children with MD

Answer 20

• Avoid over-exertion
• Avoid immobilization
• Cycling, swimming, walking
• Monitor for scoliosis

Question 21

For MD, what do you stretch and what do you strengthen?

Answer 21

Strengthen:
abdominal
hip extensors
hip abductors
knee extensors

Stretch: 
gastrocsoleus 
hip flexors 
knee flexors 
TFL/ITB

Question 22

Children with CP are typically not walking past what age?

Answer 22

10-12 years

Question 23

What are the predictors for cessation of walking?

Answer 23

– inability to rise from floor – inability to ascend steps – frequent falls
– strength decrease by 50% (dynamometer)
– ROM is a key determinant (experience/book) because of c of g

Question 24

True or false: most children with MD do not under go surgeries.

Answer 24

False
• Not uncommon in this population
– Release of hamstrings, hip adductors, hip
flexors and achilles are all common
– Usually achilles release there is a cast
– ROM as per surgeon
– Positioning immediately
– Most often weight bearing begins 2nd day post-op/ right away

Question 25

Facts about scoliosis and MD

Answer 25

• 25% of children with DMD have scoliosis before
cessation of walking
• poor sitting posture contributes to development
• impacts on maximum vital capacity
• spinal orthoses
• custom molded seat inserts
• modular seating inserts
• surgery, performed earlier with hardware is more common now

Question 26

Respiratory failure/ pulmonary complications are a major contributor to death of ___% patients

Answer 26

75%

Question 27

___________________ is a hallmark sign

of pre-terminal stage DMD

Answer 27

Respiratory insufficiency

Question 28

True or false: being put on respiratory assistance significantly decreases children with MD’s quality of life.

Answer 28

• Bach et al (1991) - surveyed 82 vent-assisted individuals, vast majority reported positive affect & satisfied with life despite physical dependence

• Colbert (1989) - reported increased
longevity from 19yrs. 9mos. to 25yrs.
9mos. in individuals who use vent.
assistance

Question 29

Becker’s Dystrophy stats

Answer 29

• Not as progressive
• incidence 1 in 20,000 births
• progression similar to DMD but slower
• longevity into 40’s, initially identified in late childhood, early adolescence

• Research:
– onset 11 yrs. – inability to walk 27 years – death 42 years

Question 30

Which type of MD is not progressive?

Answer 30

Congenital myopathy