Duchenne Muscular Dystrophy Flashcards
What is DMD the result of?
mutations in dystrophin gene (protein)
results in progressive muscle degeneration
What kind of genetic mutation is DMD?
X linked recessive (though can occur secondary to a spontaneous mutation
how does the weakness progress?
Proximal to distal
Who are the carriers?
Women are the carriers but usually exhibit no symptoms
When is there loss of ambulation without Tx?
Typically between 7-12 y.o.
Can the natural history be changed? if yes how?
Yes, by targeting interventions to known manifestations and complications. (steroids, etc)
When is DMD typically diagnosed?
5 years of age
What are the initial sx?
Abnormal muscle function.
Delayed walking, frequent falls, difficulty running/climbing stiars, gowers sign, gait abnormalities, pseudo hypertrophy of calves, increased CK
DMD effects on MSK system
Mechanical damage; increased permeability of muscle membrane, reduced blood flow to skeletal muscle during exercise, decreased bone mineral density.
What does mechanical damage lead to?
Decreased tissue compliance/elasticity, loss of regenerative capability, fibrosis, increased collagen density, reduced maximal force production and fatigue resistance.
What is mechanical damage?
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)
Stages of DMD
Pre-Symptomatic Early ambulatory Late ambulatory Early non-ambulatory Late non-ambulatory
Pre-symptomatic DMD
Possible developmental delay (freq falls, dealyed motor milestones etc)
Gait abnormalities not typically evident
Generally not Dx during this phase
Early Ambulatory DMD
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
Late ambulatory DMD
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
Early non-ambulatory
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
Late non-ambulatory
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
Pharmocological interventions
Glucocorticoids
Deflazacort
Glucocorticoids
currently the only med that slows decline in muscle strength and function in DMD. Helps preserve ambulation, minimize resp, cardiac and orthopedic complications.
Deflazacort or Prednisone
Work similarly. Deflazacort not currently approved by FDA. lower risk of weight gain.
Initiatio of Glucocorticoid therapy
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.)
Use of glucocorticoids after loss of ambulation
Medication continued to help preserve upper limb strength, reduce progression of scoliosis, and delay decline in respiratory and cardiac function
Glucocorticoids side effects
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
areas of psychosocial risk
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)
Respiratory intervention
Volume recruitment Manual/Mechanical assisted cough Nocturnal ventilation (BiPAP) Daytime ventilation Tracheostomy
Cardiac function
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
If theres back pain whats the red flag thought?
Vertebral Fracture
Role as a PT
systematic documentation of disease progression, prolong independence, slow progression, improve QOL.
PT assessment
Hx (# falls), strength, PROM (every 3-6 mo), posture/symmetry, Gait, Timed testing, motor function scales
What should you check PROM of?
Heelcords Hamstrings Hip flexors Iliotibial bands Knee extension Long finger flexors Pronators Elbow extension Shoulder abduction/flexion
Periodic therapy
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
Consultative Therapy
As necessary
Due to change in status or new technology/equipment availability
What should be a primary focus of therapy?
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)
What kind of orthotics are good for this?
Night time resting AFOs set at comfortable end range dorsiflexion. - goal is not to stretch
AFOs during ambulation are not indicated
Early Ambulatory AD
Lightweight manual mobility device to be pushed for long distances
Adapted stroller
Ultra-lightweight manual w/c
Late Ambulatory AD
power assist wheelchair
Exercise recommendations
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
