Muscular Dystrophy Flashcards
1
Q
What is muscular dystrophy
A
- a disease of muscle
- single gene defect
- x linked genetic disorder that mothers pass on
- causes protein deficiency of dystropin leaving cells fragile
2
Q
Incidence of muscular dystrophy
A
- gene abnormality but is not inherited
- approximately 250,000 individuals in the US are affected by some form of muscular dystrophy
3
Q
Classifications of MD
A
- duchenne’s
- becker’s
- congential
- congential myotonia
- childhood-onset facioscapulohumeral
- emery dreifuss
4
Q
Duchennes muscular dystrophy
A
- onset: 1-4 years
- X-linked inheritance
- course: rapidly progressive; loss of walking by 9-10 years
- death in late teens
5
Q
Becker’s muscular dystrophy
A
- onset 5-10 years
- X-linked
- slowly progressive
- maintain walking past early teens
- life span into 3rd decade
6
Q
Congenital
muscular dystrophy
onset:, inhertiance, course
A
- birth
- recessive trait
- typically slow but variable
- shortened life span
7
Q
Congential myotonic: muscular dystrophy
A
- birth
- dominant trait
- typically slow with signigicant intellectual impairment
8
Q
Childhood-onset facioscapulohumeral muscular dystrophy
Onset:
Inheritance
Course:
A
- Onset: first decade
- Inheritance: dominant/recessive trait
Course:
- slowly progressive loss of walking later life
- variable life expectancy
9
Q
emery-dreifuss
muscular dystrophy
onset, inhertiance, progression
A
- childhood to early teens
- X-linked
- slowerly progressive with cardiac abnormality and normal life span
10
Q
Muscular dystrophy: criteria for classification of the various forms of MD include
A
- mode of inheritance
- age of onset
- rate of progression
- localization of involvement
- musclar morphologic changes and presence of genetic marker
11
Q
How is a dystrophy diagnosised
A
- patient’s signs and symptoms
- medical history
- genetic testing to identify specific gene markers and mutation subtypes
- blood test to test enzymes, muscle related proteins
- EMG to pinpoint weakness muscles nerve vs muscle origin
- muscle biopsy
12
Q
Muscular dystrophy: CDC diagnosis timeline
A
- age 2.5: first sign or symptom noticed by parent/caregiver
- age 3.25: child taken to pediatrician or PCP for evaluation
- age 5: diagnosis of Duchenne muscular dystrophy based on muscle biopsy or DNA testing
13
Q
Duchenne and Becker muscular dystrophy typical characteristics
A
- upper legs and upper arms are generally affected initially
- BMD have longer longevity to the 40s
- psuedohypertrophy of the calves is a predominant feature
- clumsy
- DMD and BMD can have same symptoms and are caused by mutations in the same gene
- BMD symptoms can begin latera in life nad be less severe than DMD
14
Q
Duchenne muscular dystrophy
typical timeline for these children
A
- begins with progressive proximal weakness at age 4 years
- usually diagnosised at age 5
- at age 10 ambulation ceases
- some have cognitive delays
- the median age of survival in males with DMD was 23.7 years
- steriods, cough assist, and scoliosis surgery were linked to prolonged survival in males
15
Q
What does the lack of dystrophin do
A
- causes muscle damage and progressive weakness
- fragility of muscle membrane stability during muscle contraction
- muscle hypoxia due to impaired vasodilation when exercising
16
Q
Congential muscular dystrophy
Genetic trait type? onset? Most common form of CMD? presentation?
A
- autosomal recessive
- onset in utero and infancy
- merosin-negative muscular dystrophy is the most common CMD
- early onset hypotonia
- delayed motor milestones, contractures, normal congitive ability and diffuse brain white matter changes
17
Q
What is the definition of congential muscular dystrophy
A
- clinically and genetically heterogeneous group of inherited muscle disorders defined by early onset of hypotonia and muscle weakness
18
Q
What is limb-girdle muscular dystrophy
A
- is a group of inherited neuromuscular diseases with at least 34 variants or subtypes that all cause progressive muscle weakness
- fourth most common dystrophy
- 34 types subtypes 1(8) and subtype 2(26)
19
Q
Limb girdle MD impairments
A
- varying severity including resp. problems
- skeletal muscle weakness (progressive)
- begins with the muscles of the shoulder, and hip and later extends to the arms and legs
- waddling gait, difficulty with stairs, difficulty rising from sitting
- difficulty carrying heavy objects or reaching overhead
- eventually needs AD
20
Q
Childhood-onset facioscapulohumeral
typical presentation
A
- also known as landouzy-dejerine muscular dystrophy
- initially weakness of facial, shoulder and or upper arm muscles
- eventually develop weakness of hips and thighs and/or involved of LE muscles
- slow disease progression
- approximately 20% of affected individuals eventually require a wheelchair
- life expectancy is not shortened
21
Q
Emery dreifuss
Typically affects what muscles
A
- affecting the muscles of the arms, legs face, neck, spine and heart
- EDMD is believed to be the third most common form of muscular dystrophy
- some people with autosomal dominant form experience heart problems without any weakness or muscle wasting
- people with emery-dreifuss muscular dystrophy develop heart probelms by adulthood
22
Q
Impairments with muscular dystrophy
A
- muscle weakness
- contractures
- cognitive deficits
- mobility
- cardiac
- respiratory
- scoliosis
- obesity
23
Q
Typical posture of muscular dystrophy
A
- sway back
- weak butt muscles
- knees may bend back to take weight
- thick lower leg muscles
- tigh heel cord
- belly sticks out due to weak belly muscles
- thin weak tights
- poor balance
- awkward, clumsy if walking
24
Q
What is meryons sign
A
- sign of muscular dystrophy
- when your child slides through your hands
25
Gowers sign
- muscular dystrophy sign (can be)
- child has trouble getting up to standing
26
Timed gowers sign test
- typical child 1 second
- mild group: 3 seconds
- moderate group 8 seconds
- severe group 21 seconds
27
the motor function measure
- tool that can be used for most neuromuscular conditions and is applicable to all degrees of severity in ambulant and non-ambulant patients
- the MFM contains 32 items divided into 3 domains
- it can be predicted that a patient will lose the ability to walk within a year when the standing and transfer score is less than 40% or the total score is less than 70%
- to predict when the loss of ambulation will occur
28
other outcome tools: muscular dystrophy
- MMT
- 6 minute walk test
- north star ambulatory assessment scale
- time taken to climb four steps
- time taken to rise from the floor
- performance of upper limb
29
treatments: muscular dystrophy
- symptomatic interventions
- practice recommendations regarding the prescription of exercise should stress the uncertainty surrounding utility of muscle exercise
- patients today must decide whether to start or continue exercise on the basis of expert opinions or anecdotic experience at best
30
How does exercise
| help muscular dystrophy
- Helps/does not help/detrimental
- conflicting research
- AVOID eccentric exercise and resistive high load exercises with DMD
- isometrics are acceptable or body weight resistive
- w/ BMD, Fasciohumeral, limb girdle dystrophies resistive exercises are approced
- child dependent
31
DMD medical interventions
- steriods (either prednisone or deflazacort)
- impede inflammatory fibrosis and improve muscles strength
- an initial increase in strength in the first 6 months to one year patients on medication
- often exhibit a slow decline after 18 months
- most methods of rehab become ineffective by the second decade of life
32
PT with muscular dystrophy
- stretching: family HEP
- monitor skin integrity
- equipment
- provide community support clinics
- orthotics
- monitor scoliosis
- exercise
- gait
- ADLs
33
research with muscular dystrophy
- it is hypothesized that children with DMD, bend their trunk backwards to keep the center of gravity behind the hips to prevent jackknifing at the waist
- It has also been suggested that to compensate for increasing knee, extensor weakness. They stabilize the knee by keeping the center of gravity in front of it.
- EMG activity of proximal muscles is abnormal and DMD, as has previously been suggested since these muscles are the most affected by DMD. This confirms the hypothesis that hyperactivity compensate for weakness.
- This suggests that 4 foot contact which is a characteristic of the gate, is an adaptive mechanism rather than a gait anomaly
34
Gait Ropars
- significantly greater muscle coactivation was found in the children with DMD
- coactivation of the knee muscles likely helps the child to maintain the center of gravity both behind the hips and in front of the knees
- since the motor command is normal in DMD the hyperactivity and co-contractions likely compensate for the gate, instability and muscle weakness however, may have negative consequences on the muscles and may increase the energy cost of gait
- Simple Rehabilitative strategies such as targeted physical therapies maty improve stability and thus the pattern of muscle activity
35
Vignos functional rating scale for duchennes muscular dystrophy
1. walks and climbs stairs without assistance
2. walks and climbs stairs with aid of railing
3. walks and climbs stairs slowly with aid of railing
4. walks but cannot climb stiars
5. walks assisted but cannot climb stairs or get out of chair
6. walks only with assistance or with braces
7. in wheel chair: sits errect and can roll chair and perform bed and wheelchair ADLs
