definition
The muscular dystrophies (MD) are a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles that control movement. There are many forms of muscular dystrophy, some noticeable at birth (congenital muscular dystrophy), others in adolescence (Becker MD), others in adult-hood (Myotonic).
Duchenne muscular dystrophy (DMD)
- An inherited disease
- Carried on the X chromosome that primarily affects boys (girls can carry the gene that causes the disease, but they usually have no symptoms).
incidence for DMD
1 in 3,500 males for Duchenne muscular dystrophy
etiology for DMD
- DMD occurs when a particular gene on the X chromosome fails to make the protein dystrophin.
- This protein stabilizes the muscle membrane during contraction. When dystrophin is deficient, the muscle degenerates.
diagnosis of DMD
- blood test: CK level (creatine kinase) an enzyme that leaks out of damaged muscle.
- usually means muscle is being destroyed by some abnormal process, such as a muscular dystrophy or an inflammation.
• muscle biopsy is preformed to pinpoint the specific dystrophy
phase 1: preschooler/transitional phase
Onset is between 3-5 years and progresses rapidly (typically when children are diagnosed)
• late in learning to walk
• may notice enlarged calf muscles, or pseudohypertrophy. may seem clumsy and fall often.
• child begins to “toe” walk in order to compensate for beginning proximal weakness in pelvis.
**Proximal weakness in hips and shoulders is a hallmark feature of DMD.
gower’s sign
Proximal muscle weakness forces the patient to use arms to push up trunk and “climb up the legs” when rising from the floor. Soon, child has trouble climbing stairs, getting up from the floor or running.
stage 2: school age/immobility
- continue to walk on his toes or the balls of his feet, with a slightly rolling gait.
- waddling and unsteady gait and can easily fall over. anterior pelvic tilt, projecting the belly out, and puts the shoulders back.
- difficulty raising his arms above shoulder level.
- lose the ability to walk sometime between ages 7 and 12.
stage 3: adolescent/end stage
• wheelchair users
• Some rely on a ventilator to breathe.
• Many boys will not live past 20 years of age.
• Activities involving the arms, legs or trunk require assistance or mechanical support
• This period is characterized by:
o Respiratory problems (pneumonias)
o Infections
o Cardiac Arrest
healthcare management
- no medical treatment to stop/reverse dystrophic process
- antibiotics for secondary infections
- pulmonary treatments
- gene therapy?
- surgeries: spinal fusion for scoliosis, heel cord lengthening
- meds: steroids for strength, slow progression of disease, improve lungs/endurance
OT
main goal:
- maintain child’s independence and minimize contractors, provide adaptive equipment, seating/posture, family counseling
- adjunct therapies: aquatics, hippotherapy
end of life issues
A difficult performance area to address in a child with a progressive disease is activities of daily living. Many times, adults take away the independence that an ill child had previously acquired. Parents and caregivers many times “jump” to perform an activity such as dressing or eating to save the child’s strength.
• By doing this, are the parents taking away the vestiges of independence that remain for the child?
• Could this affect the child’s perception of control over the situation?
• Could energy conservation techniques be used to help children make the most of their energy reserves?
• How can adaptive equipment be beneficial for energy conservation? (examples…)
spinal muscular atrophy
genetic disorder characterized by weakness and wasting (atrophy) in muscles used for movement (skeletal muscles). It is caused by a loss of specialized nerve cells, called motor neurons that control muscle movement.
• The weakness tends to be more severe in the muscles that are close to the center of the body (proximal) compared to muscles away from the body’s center (distal).
• The muscle weakness usually worsens with age.
4 SMA classifications
Type I: Acute Werdnig-Hoffmann Disease
Type 2: Chronic Werdnig-Hoffmann Disease
Type 3: Kugelberg-Welander Disease
Type 4: Adult-onset SMA
general impairments SMA
- Loss of anterior horn cells
- Weakness/fatigue
- Trunk
- Proximal joints (shoulder/pelvis)
- Cranial nerves inconsistently involved
- Contractures
- Muscle fasciculations
SMA - OT interventions
• Respiratory Care and Support
• Encourage AROM/Provide PROM and educate family
• Positioning for alignment and function – orthotic fabrication as needed
• *Movement opportunities: hammock, swings
o Typically bright children with poverty of movement!!
• Developmental activities – as appropriate for movement abilities
• Adaptive equipment – find ways to increase participation!
• Consultations to team members
o PT - gentle strengthening
o SLP – collaborate on safe and efficient feeding/swallowing
