Muscular Dystrophy Flashcards
Muscular dystrophy
Genetic
Progressive loss of muscle contractility secondary to myofibril destruction - rate varies based on type
Muscular dystrophy criteria for classification
Mode of inheritance Age of onset Progression rate Muscle morphological changes Presence of genetic markers
How many primary classifications of MD?
9
Duchenne’s MD
Most common x-linked
Variable life span - late teens/early 20s up to end of 3rd decade
Ab/missing dystrophin - acts as anchor in intracellular lattice to enhance tensile strength
DMD Tx research - Myoblast transfer therapy
Infection of skeletal muscle precursor from donor into muscle of individual with MD - stem cell will grow and mutate w/ surrounding cells
Low efficacy
DMD Tx research - gene replacement
Introduction of dystrophin gene placed in vector
DMD long term corticosteroid use
Improve outcome - prolonged ind. and assisted walking by up to 3y
Improved pulm function
Side effect: weight gain, growth suppression, osteoporosis
DMD classical clinical manifestion onset at ____
4-5 yrs
DMD muscle weakness
Initially in neck flexor, ab, interscap and hip ext musculature
More generalized progression
DMD impairments
Post calf enlargement ROM WNL prior to age 5 (gast/sol and TFL tightness first) Lordotic standing posture increased Scap wing Scoliosis
DMD infant to pre school
S/s no evident this young
DMD mean dx age
5 urs
DMD initial disability occurs by age 5
Clumsiness, falling, inability to keep up w/ peers
Gait mildly atypical
Unable to run or jump
Growers sign
DMD age 6-8
Stair negotiation and standing from floor more difficult
Gait - inc BOS, trendelenburg, lateral sway, shoulder retraction, reduced arm swing
Toe walking - initial comp for weak ab and hip ext —> lordosis and forward shift of COM
DMD 8-10
Toe walk (post calf contract) In toe w/ TFL (weak iliopsoas) Falls Fatigue during amb Progressive decline in pulm, MVC
DMD adolescence
Walking lost for most mobility (age 10-12)
Transfers increasingly difficult
W/C
Difficult ADLS
Contractures should be maintained through position and activites, man stretching discont.
DMD and exercise
Overexertion and immobilization detrimental
Submax ther ex beneficial -only for motivated families
Cycling and swimming
Standing and walking min 2-3hrs/day
Key muscles for DMD if ther ex early
Abs
Hip ext
Hip ab
Knee ext
DMD and breathing exercise
Short to slow loss of VC and FEFR
DMD EStim
Slow progression of weakness
DMD home exercise
ROM - hold 30-60 sec
Prone to sleep to slow flex contracture (splinting)
Modify/exclude physical fitness test that includes push up, sit up, timed running
Scoliosis check
DMD addressing falls and fatigue in 8-10 age range
Guard on stairs and amb
Man W/c while child can propel
Motorized scooter should be considered to increase ind.
DMD cont of walking
Personal decision by child/family
Standing slows progression of contracture - KAFO
Stand pivot transfer regresses to 1-2 man lift. (Tub lift and bath chair required)
Add vignos scale
L
DMD mobility/spinal alignment
Power scooter for transition to power chair
Manual chair possible
Fit! Sold back, lateral trunk and lumbar support, add pads seat belt, chest strap, foot rest to support neutral ankle, midline joystick
Neutral or slight ext of spine to slow scoliosis
DMD exercise
Shift emphasis from LE to UE, bilateral and encourage them assist w/ AD
Rom include stretch of shoulder and elbow
DMD home medications
Wheeled commode, bath chair, hand held shower, urinal
Airflow mattress, egg crate cushion or hospital bed
Position program throughout night to prevent skin breakdown
DMD transition to adulthood
Greater reliance on AT for enviro access and ADL
Social considerations
Environmental control until on power chair to access other technology
Breathing exercise
Postural drainage
Intermittent pressure breathing tx
DMD - vent
- CPAP when FVC <30% of age adjusted norm
- Assisted vent w/ trach when resp insufficiency is present with ab blood gas levels during day or night
- preterminal stage
75% of children w/ DMD pass away from ______
Respiratory infections
Becker muscular dystrophy
More slowly progressive variant of DMD
Dystrophin present in reduced amounts/abnormal size
Initial s/s not I before late child/early adolescence
Frequently report muscle cramping
Mean onset for BMD
11
Inability to walk at 27
Death 42 years
BMD impairments
Same as DMD, less severe
Higher cardiac involvement than DMD
Contracture may be present when walking no longer possible
Initial clinical signs of BMD
Frequent falls and clumsiness in mid to late teens
BMD sig diability develops in
Mid twenties for most
Limiting factor for longevity in BMD
Complications for dilated cardiac myophathy
Congenital muscular dystrophy
Group of muscle disorders w/ onset in utero/during 1st year
Characterized by onset of congenital hypotonia, delayed motor development, early onset of progressive weakness
Reported forms of congenital muscular dystrophy
Congenital MD w/ CNS (fukuyama syndrome, walker Warburg disease, muscle eye brain disease)
Meiosis diffident congenital MD
Inter grin deficient congenital MD
Congenital MD w/ normal merosin
Spinal muscular atrophy - childhood onset type 1
Werdnig haoffman (acute)
0-3 mo onset
Recessive inheritance
Rapid progression, severe hypotonia, death w/in. First year
Spinal muscular atrophy childhood onset type 2
Werdnig- Hoffman (chronic) 3m-4y onset Recessive inheritance Rapid progressive that stabilizes Moderate/severe hypotonia Shortened life span
Juvenile- onset type 3 spinal muscular atrophy
Kugelber-welander 5-10 yr onset Recessive Show progressive Mild impairment
SMA dx
Autosomal recessive w/ genetic defect on chromosome 5
Survival motor neuron - (ant horn cells, w/out = apoptosis)
Abnormal ant horn cells
Werdnig Hoffman SMA incidence
Type 1 and 2 account for 47% of SMA
SMA objective
Goni, myometry, mmt, pulm function 6 min walk North Star amb assessment Revised Upper limb module for SMA Motor function measure PEDI PEDS QL Egen klassifikation scale
Acute childhood SMA type 1 impairments
Primary: muscle weakness secondary to loss of ant horn
Contractures w/ acute onset
Inconsistent CN involvement
Secondary imp: contractures, scoliosis
Acute childhood SMA type 1 tx
feeding, ROM, positioning, respiratory care
SMA type 1 infancy
Weak/absent fetal movement during last months preg.
Sig weakness at birth (antigravity w/ pelvic or shoulder)
Resp. Care is central focus
POE not attained
Supported sitting for only short periods. Avoid fatigue
Mean age of death for SMA type 1
6 mo
1-21 months is typical range
Chronic childhood SMA type 2
Sig weakness in first year of life
Proximal muscle weakness
Chronic childhood SMA type 2 subgroups
Most severely involved - never develop ability to sit alone and resp capacity severely reduced
Intermediate - sits alone but never able to walk. FVC regress to 45% by age 10
Least sever - (I) walking attained, 50% then lose by end of first decade
SMA type 2 infancy
15% show impairments w/in first 3 mo
Sitting posture primary concern
Avoid fatigue
If child not standing by 16-18 mo, adaptive equipment should be considered
SMA type 2 preschool/school age
Toddler may require KAFO standing - walking may be unrealistic goal
Invitation walking program in II bars followed by walker
Power mobility for those not (I) - change side of joystick every 6 mo
SMA type 2 hip dislocation and contracture occur less often when ____
Supported wlaking program is utilized
SMA type II progress to adulthood
Survival into adulthood extremely variable
Intelligence is rarely affected
Aggressive pulm care required
ROM continuation, control contractures
Juvenile onset SMA (3)
Onset later in 1st debate - may have weakness in first year in proximal hip and shoulder girdle
Juvenile onset SMA impairments
Proximal LE weakness MC
Secondary: post compensations due to muscle weak, contracture, scoliosis
Increased lordosis, trandelenburg
PF contracture frequent
Incidence of scoliosis and severity related to degree of weakness and functional status.
SMA
Second most common group of fatal recessive disease
