NM Disorders Flashcards
Most common MD (I in 3500 live births); X-linked recessive; occurs directly in the muscle; diagnosed typically at 5 years, initial sx at 2.5; life span = 20-30 years
Duchenne MD
- not walking by 18 mos = red flag
What enzyme do people with DMD lack?
dystrophin
What is the significance of decreased dystrophin enzyme?
Decreased enzyme = fragile structure and cannot repair
- you do not want to fatigue m’s so breakdown does not occur
- causes calcium channel leaks with unstable musculature
What are symptoms of DMD?
- Delay in walking
- Difficulty getting off the floor; Gower’s sign
- Clumsiness or frequent falling
- Pseudohypertrophy of the calves; Firm to palpation; decreased necrosis
How is DMD diagnosed?
Based on clinical examination:
- EMG
- Muscle Biopsy
- DNA Analysis
- Laboratory Blood Tests
What is the role of the PT in DMD?
- Identify impairments in body structure and function
- Promote activity and participation - MDA camp
- Prevent secondary complications
- Education
What are secondary impairments of DMD?
- Development of contractures
- Postural misalignment - Especially in anti-gravity positions
- Development of Scoliosis
- Decreased respiratory capacity
- Fatigue
- Obesity
- Mild Intellectual Impairments or Learning Difficulties
What is the role of the PT in educating about signs that precurse declines in function and increases in disability?
- Loss of ambulation
- Accommodation for adaptive equipment
- Transition from educational to vocational environment
- Decisions regarding mechanical ventilation
MD type: onset 1-4 years; X-linked; Rapidly progressive; loss of walking by 9-10 years; death in late teens
Duchenne’s
MD type: onset 5-10 years; X-linked; Slowly progressive; maintain walking past early teens; life span into third decade
Becker’s
MD type: onset at birth; Recessive; Typically slow, but variable, shortened life span
Congenital
MD type: onset at birth; Dominant; Typically slow with significant intellectual impairment
Congenital myotonic
MD type: onset in first decade; Dominant/Recessive; Slowly progressive loss of walking in later life, variable life expectancy
Child-onset Facioscapulohumeral
MD type: onset in childhood to early teens; x-linked; Slowly progressive with cardiac abnormality and normal life span
Emery-dreifuss
What are primary impairments of MD?
- Muscle Weakness secondary to progressive loss of myofibrils
- Contractures from birth - Congenital; Congenital Myotonic
What are goals of treatment for MD?
- Promote independence
- Slow progression
- Improve quality of life
What are pharmacologic management of DMD?
- Use of steroids
- Experimental use of stem cells
- Experimental gene replacement therapy
What is medical management of DMD?
- Steroids (weak evidence for creatinine use)
- Surgical contracture management
- Conservative management of scoliosis through bracing
What are side effects of steroid use?
- Weight Gain
- Growth Suppression
- Osteoporosis
What are impairments seen with DMD?
- Initial weakness occurs in the neck flexors, abdominals, interscapular, and hip extensor muscles
- Generally, as the disease progresses weakness moves from a proximal to distal pattern
- MMT Dynamometry can be used to predict loss of ambulation
- Timed functional activities have been correlated with strength - 5x STS, 3/6/9 min walk test, TUG, TU from floor, gait speed
What posture abnormalities do you see with DMD?
- increased lordosis - due to ab weakness
- compensatory winging of scap - maintains COM post to hip
- onset of scoliosis usually just before adolescence - affects 75-90% of non-ambulatory
Would you use an orthotic in a child with DMD?
Floor reaction AFO if no knee flexion contracture present
- AFO incr stress on quads
- KAFO increases energy cost, taxing CV system
- likely to lose ROM with gastroc/soleus complex first
What are the grades for functional ability on vignos scale: UEs?
1 = pt can ABD arms in full circle until they touch above head 2 = pt can rain arms above head only by flexing elbow 3 = pt cannot rain hands above head but can raise 8oz glass of water to mouth 4 = pt can rain hands to mouth but not a glass 5 = pt cannot rain hands to mouth but can hold a pen or pick up pennies from table 6 = pt cannot raise hands to mouth and has no useful function of the hands
What are the grades for functional ability on vignos scale: LEs?
1 = walks and climbs stairs w/o assistance 2 = walks and climbs stairs with the aid of a railing 3 = walks and climbs stairs slowly (>12s for 4 stairs) with the aid of a railing 4 = walks unassisted and rises from chair, but can't climb steps 5 = walks unassisted but cannot rise from chair or climb stairs 6 = walks with assistance or walks independently with long leg brace 7 = walks in long leg braces but requires assistance for balance 8 = stands in long leg braces but unable to walk 9 = in w/c 10 = confined to bed
What assessment is used in DMD to indicate significant loss in of function?
North Star ambulatory assessment
What kind of strengthening contraction should be avoided with DMD?
eccentric
How can you predict the cessation of walking in DMD?
- walking ceases around 10-12 years; predicted by 50% reduction in leg strength; mmt < 3 for hip ext and < 4 DF
- cessation of walking w/in 2-2.5 years when 5-12s needed to ascend 4 steps
SMA type: onset 0-3 months, recessive inheritance; Rapid Progression, Severe Hypotonia, Death <1 year old
Childhood-Onset Type I Werdnig-Hoffman (Acute)
- no ambulation
SMA type: onset 3 months - 4 years, recessive inheritance; Rapid Progression followed by stabilization, Moderate to Severe Hypotonia, Decreased Life span
Childhood-Onset Type II Werdnig-Hoffman (Chronic)
- no ambulation
SMA type: onset 5-10 years, recessive inheritance; Slowly Progressive, Mild Impairment
Juvenile-Onset, Type III Kugelberg-Welander
Pathophysiology: Abnormality of the large anterior horn cells in the spinal cord resulting in progressive degeneration of the remaining cells and correlated loss in function secondary to significant weakness; Diagnosis: clinical examination, laboratory testing, EMG, muscle biopsy, and genetic testing
Spinal musclular atrophy
What are primary impairments of SMA?
- Inconsistent cranial nerve involvement
- Contractures - Equinovarus
- Muscle fasciculations, especially of the tongue
- Impaired Strength - In Types I & II: Poor head control; Delayed motor milestone achievement
What are secondary impairments of SMA?
- Scoliosis
- Contracture
- Decreased respiratory function
What interventions are used for SMA?
- Prevent contractures - happen a lot quicker so adaptive equipment considered sooner
- position
- provide adaptive equipment - start power mobility at 18 mos
- work on strength in developmentally appropriate progressions
- teach compensatory strategies when needed - dependent in transfers
