Duchenne Muscular Dystrophy

Question 1

What is DMD the result of?

Answer 1

mutations in dystrophin gene (protein)

results in progressive muscle degeneration

Question 2

What kind of genetic mutation is DMD?

Answer 2

X linked recessive (though can occur secondary to a spontaneous mutation

Question 3

how does the weakness progress?

Answer 3

Proximal to distal

Question 4

Who are the carriers?

Answer 4

Women are the carriers but usually exhibit no symptoms

Question 5

When is there loss of ambulation without Tx?

Answer 5

Typically between 7-12 y.o.

Question 6

Can the natural history be changed? if yes how?

Answer 6

Yes, by targeting interventions to known manifestations and complications. (steroids, etc)

Question 7

When is DMD typically diagnosed?

Answer 7

5 years of age

Question 8

What are the initial sx?

Answer 8

Abnormal muscle function.
Delayed walking, frequent falls, difficulty running/climbing stiars, gowers sign, gait abnormalities, pseudo hypertrophy of calves, increased CK

Question 9

DMD effects on MSK system

Answer 9

Mechanical damage; increased permeability of muscle membrane, reduced blood flow to skeletal muscle during exercise, decreased bone mineral density.

Question 10

What does mechanical damage lead to?

Answer 10

Decreased tissue compliance/elasticity, loss of regenerative capability, fibrosis, increased collagen density, reduced maximal force production and fatigue resistance.

Question 11

What is mechanical damage?

Answer 11

Dystrophin provides stability to muscles during function, without it muscle is more vulnerable to damage. Dystrophin increases tensile strength. Chronic damage/muscle breakdown (increased serum CK)

Question 12

Stages of DMD

Answer 12

Pre-Symptomatic
Early ambulatory
Late ambulatory
Early non-ambulatory
Late non-ambulatory

Question 13

Pre-symptomatic DMD

Answer 13

Possible developmental delay (freq falls, dealyed motor milestones etc)
Gait abnormalities not typically evident
Generally not Dx during this phase

Question 14

Early Ambulatory DMD

Answer 14

GOWERS SIGN!
Waddling gait/duchenne jog
Can climb stairs with compensatory pattern
May see some imp in gross motor but plateau eventually
No specialized mobility equipment typically needed prior to school age

Question 15

Late ambulatory DMD

Answer 15

Increasingly labored gait
Loss of ability to climb stairs and rise from floor ind
Difficulty with antigravity extension
inc LE contractures with dc amb
decreased mot to participate
access to mobility device may help keep up with peers

Question 16

Early non-ambulatory

Answer 16

Typically able to sit ind, bed mobility may be difficult
Often need adaptive equipment and some assistance with bathing, toileting, and transfers
might be able to self propel wheelchair might not
increased risk for scoliosis

Question 17

Late non-ambulatory

Answer 17

UE function, postural maintenance and bed mobility increasingly limited.
Increased need for caregiver assistance for all ADLs/repositioning
Increasing need for assistive technology
Increasing use of respiratory support
Increasing reports of chronic pain

Question 18

Pharmocological interventions

Answer 18

Glucocorticoids

Deflazacort

Question 19

Glucocorticoids

Answer 19

currently the only med that slows decline in muscle strength and function in DMD. Helps preserve ambulation, minimize resp, cardiac and orthopedic complications.

Question 20

Deflazacort or Prednisone

Answer 20

Work similarly. Deflazacort not currently approved by FDA. lower risk of weight gain.

Question 21

Initiatio of Glucocorticoid therapy

Answer 21

not rec for child who is still gaining motor skills, rec during plateau phase (no progress with motor skills, prior to decline (4-8 y.o.)

Question 22

Use of glucocorticoids after loss of ambulation

Answer 22

Medication continued to help preserve upper limb strength, reduce progression of scoliosis, and delay decline in respiratory and cardiac function

Question 23

Glucocorticoids side effects

Answer 23

Cushingoid features
Weight gain, obesity
Growth suppression 
Bone demineralization
Increased fracture risk 
Adverse behavioral changes
Delayed puberty
Increased susceptibility to infection
Hypertension
Glucose intolerance
Cataracts

Question 24

areas of psychosocial risk

Answer 24

Social functioning due to biological or physical limitations
Learning disorders and/or cognitive delays
Speech and language deficits
Neurobehavioral and/or neurodevelopmental disorders
Oppositional/argumentative behavior
Anxiety or depression (patient and family)

Question 25

Respiratory intervention

Answer 25

Volume recruitment
Manual/Mechanical assisted cough
Nocturnal ventilation (BiPAP)
Daytime ventilation
Tracheostomy

Question 26

Cardiac function

Answer 26

cardiomyopathy and arrythmias common, baseline of cardiac function at Dx important. (at least before 6 y.o.) - cardiac meds: ace inhibitors, beta blockers, diuretics.
GLucocorticoids = hypertension

Question 27

If theres back pain whats the red flag thought?

Answer 27

Vertebral Fracture

Question 28

Role as a PT

Answer 28

systematic documentation of disease progression, prolong independence, slow progression, improve QOL.

Question 29

PT assessment

Answer 29

Hx (# falls), strength, PROM (every 3-6 mo), posture/symmetry, Gait, Timed testing, motor function scales

Question 30

What should you check PROM of?

Answer 30

Heelcords
Hamstrings
Hip flexors
Iliotibial bands
Knee extension 
Long finger flexors
Pronators
Elbow extension
Shoulder abduction/flexion

Question 31

Periodic therapy

Answer 31

Monthly or at regularly scheduled intervals
Usually every 3-6 months for this population
Monitor ROM, assess function, provide treatment and update home program
We follow Clinical Pathways/Algorithms to guide frequency and intervention

Question 32

Consultative Therapy

Answer 32

As necessary

Due to change in status or new technology/equipment availability

Question 33

What should be a primary focus of therapy?

Answer 33

Active, passive, positional (prolonged elongation) stretches –> Heelcords (primarily gastroc), hamstrings, hip flexors, IT bands, pronators, long finger flexors
Knee extension, elbow extension, shoulder abduction/flexion
Long sitting with AFOs for hamstrings and heelcords
Wedge standing, runners stretch for heelcords
Frequency: daily (at home, school, and clinic)

Question 34

What kind of orthotics are good for this?

Answer 34

Night time resting AFOs set at comfortable end range dorsiflexion. - goal is not to stretch
AFOs during ambulation are not indicated

Question 35

Early Ambulatory AD

Answer 35

Lightweight manual mobility device to be pushed for long distances
Adapted stroller
Ultra-lightweight manual w/c

Question 36

Late Ambulatory AD

Answer 36

power assist wheelchair

Question 37

Exercise recommendations

Answer 37

Some recommend sub-maximum aerobic exercise while others emphasize avoidance of overexertion and overwork weakness
High-resistance strength training and eccentric exercise are inappropriate across the lifespan
Muscle pain or myoglobinuria in 24 hour period after activity sign of overexertion and contraction-induced injury
Aquatic therapy and swimming may be appropriate
Education regarding energy conservation is appropriate