Muscular Dystrophy and Related Disorders

Question 1

Disorders of motor nerve

Answer 1

Polio
CMT
ALS

Question 2

Disorders of NMJ

Answer 2

Myasthenia Gravis

Question 3

Disorders of mm

Answer 3

Muscular Dystrophy (MD)
Spinal Muscular Atrophy (SMA)

Question 4

MD and SMA Characterized by…

Answer 4

Progressive weakness
Mm atrophy
Contracture formation
Progressive disability
Sometimes shortened lifespan
Usually of genetic origin
Not curable, but treatable

Question 5

Duchenne MD

Answer 5

Onset 1-4

X-linked - male offspring inherit the disease from their asymptomatic mothers

Rapid progression

Question 6

Becker MD

Answer 6

Onset 5-10

X-linked

Slower progression

Question 7

Congenital MD

Answer 7

Onset birth

Recessive

Slow progression

Shortened lifespan

Question 8

Congenital Myotonic

Answer 8

Onset birth

Slow progression

Significant intellectual impairment

Question 9

Fascioscapulohumeral MD

Answer 9

Onset 1st decade

Slow progression

Late loss of ambulation

Variable life expectancy

Question 10

SMA type 1

Answer 10

Aka Werdnig-Hoffman Acute

Onset 0-3 mos

Recessive

Severe hypotonia

Death within 1st year

Question 11

SMA type 2

Answer 11

Aka Wednig-Hoffman Chronic

Onset 3 mos-4 years

Recessive

Rapid progression then stabilizes

Moderate to severe hypotonia

Shortened lifespan

Question 12

SMA type 3

Answer 12

Aka juvenile onset

5-10 years

Recessive

Slow progression

Milder impairments

Question 13

Dystrophinopathy mutation

Answer 13

DMD

In gene coding for the protein dystrophin

Mm doesn’t hold together well
-Causes a disruption in the linkage btwn the subsarcolemma cytoskeleton and extracellular matrix

Eventually becomes fibrous, fatty, and non-contractile

Question 14

DMD Morbidity

Answer 14

Related to respiratory insufficiency and/or heart failure

Question 15

1/3 of DMD cases…

Answer 15

Spontaneous mutations

Rate of approx 1 in 10,000

Question 16

DMD dx

Answer 16

Blood work…

CK levels are significantly elevated

Genetic testing…

By blood work $$$

Mm biopsy…

Specimens show degeneration and loss of fibers, increased fat and connective tissue

EMG…

Low amplitude, short duration polyphasic motor unit action potentials

Question 17

Clinical Presentation DMD

Answer 17

Possible delayed onset of motor milestones, especially late walking

Tripping, falling, poor ability to run or resistance to running, inability to keep up with peers

Toe walking

Pseudohypertrophy of the calves

Progressive weakness

Lordosis

Waddling gait

Gower’s Sign

Question 18

Toe walking

Answer 18

CP
ASD
DMD

Question 19

Medical Management DMD

Answer 19

Prenatal care - genetic counseling

Early dx - CK levels

Nutritional management - obesity is a significant problem

Orthopedic management - contracture lengthening, spinal stabilization

Cardiopulmonary management - including PFT (when ambulation decreases, this problem gets worse)

Question 20

Prednisone

Answer 20

Kids that take this have some preservation of cardiopulmonary function

Question 21

DMD

Birth to 2 years

Answer 21

Late acquisition of milestones, especially walking

Question 22

DMD

3-5 years

Answer 22

Toe walking
Clumsiness
Pseudohypertrophy of calves
Gower’s Sign

Question 23

DMD

6-8 years

Answer 23

Toe walking
Lordosis
Inability to climb stairs sans assistance
Wide-based waddling gait
Can't rise from floor sans help

Question 24

DMD

9-11

Answer 24

Walks with braces - controversial
Scoliosis
May have orthopedic surgery
Beginning respiratory insufficiency

Question 25

DMD 12-14 years

Answer 25

``` Loss of ambulation Increased respiratory difficulties Obesity Contractures Progression of scoliosis Dependent for transfers Needs assist with ADL's ```

Question 26

DMD 15-17 years

Answer 26

Dependent in most ADLs | May need assisted ventilation

Question 27

DMD 18+ years

Answer 27

Totally dependent Assisted ventilation Death comes after a period of declining respiratory fx

Question 28

Scoliosis DMD

Answer 28

Develops as the age of the child with DMD increases Significant curves are generally not noticed until after 11 years of age Increases with more sitting time Becomes fixed over time

Question 29

Respiratory DMD

Answer 29

Respiratory musculature atrophies Coughing becomes ineffective Pulmonary infections become more frequent Major cause is progressive weakness of these mm

Question 30

Cardiac DMD

Answer 30

Dystrophin deficiency results in cardiomyopathy, arrhythmias, and CHF Posterobasal portion of left ventricle more affected than other parts Heart mm involvement generally occurs later than skeletal mm involvement

Question 31

Cognition DMD

Answer 31

High rate of intellectual impairments This deficit not progressive and not related to disease severity IQ scores fall approx 1 SD below mean Verbal scores affected more than performance scores

Question 32

Importance of treatment DMD

Answer 32

Proper tx can prolong QOL Parental counseling Prolong ambulation Any tx most optimal the better the pt's physical condition is

Question 33

Glucocorticoid corticosteroids DMD

Answer 33

Prednisone Deflazacort - less SEs, not FDA approved

Question 34

Creatine monohydrate

Answer 34

Natural body-building substance Increases in mm levels of creatine and improvements in maximal exercise performance and recovery from exercise in healthy subjects

Question 35

Orthopedic tx DMD

Answer 35

Spinal fixation when scoliosis exceeds 30-degrees Pelvic obliquity Achilles tendon lengthening Fasciotomies Tib post transpositions Percutaneous tenotomies

Question 36

Pulmonary tx DMD

Answer 36

Nasal positive pressure ventilation at night to assist breathing and to provide a rest for overworked respiratory mm

Question 37

Cardiac tx DMD

Answer 37

ECHO and ECG monitoring Cardiac medications for arrhythmias may be necessary

Question 38

3 phases of DMD presentation

Answer 38

Early of ambulatory stage Transitional phase during loss of ambulation Later/wheelchair stage when the child or young adult is wheelchair bound and dependent for most of his functional activities

Question 39

Functional T + M DMD

Answer 39

Stable performance or declining performance Assessing strength, pulmonary function, and functional tasks in combination PEDI 6MWT*** Brooks grades for UE VIgnos for LE

Question 40

MMT for DMD

Answer 40

Must be a routine part of the PT eval of the child with myopathy No correlation btwn rate of decline and wheelchair use Hand-held myometry and various fixed tensiometer systems have been used in attempts to better quantify mm strength in boys with DMD

Question 41

ROM in DMD

Answer 41

Loss of... Full ankle DF Knee extension Hip extension ***Important to measure

Question 42

Bracing at night

Answer 42

Important Kids should get 4-6 hours of prolonged stretch in evening or when they are asleep

Question 43

AVOID in DMD

Answer 43

Maximal resistive strength training Eccentric exercise

Question 44

GOOD for DMD

Answer 44

Submax exercise Endurance training - swimming, cycling

Question 45

Primary goal as PTs when working with pts with DMD

Answer 45

Maintenance of ambulation

Question 46

Signs of overwork weakness in pts with DMD

Answer 46

Feeling weaker rather than stronger 30 min after exercise Excessive DOMS 24-48 hours after exercise Severe mm cramping Heaviness in the extremities Prolonged SOB

Question 47

Myotonic Dystrophy (MTD)

Answer 47

Autosomal dominant disorder on chromosome 19 Symptoms first noticed during adolescence and are characterized by myotonia, a delay in mm relaxation time, and mm weakness As weakness progresses, myotonia decreases Many pts also have cognitive impairment, cataracts, diabetes, and cardiac arrhythmias These guys need very close medical management

Question 48

DMD and assistive devices

Answer 48

Don't really benefit Usually go from walking to wheelchair

Question 49

DMD Knee Flexion Extension Curve

Answer 49

When ambulation almost lost, the first loading response starts to disappear Once this occurs, they lose their ambulation within about 6 mos

Question 50

Myotonia

Answer 50

Difficulty to relax muscles

Question 51

Percussion myotonia

Answer 51

If you hit the mm bellies, they will contract

Question 52

Limb Girdle Muscular Dystrophy

Answer 52

Group of progressive mm dystrophies that affect PROXIMAL musculature Initial presentation can be quite variable extending from early childhood into adulthood Heterogeneous Gower to get up from chair Waddling gait

Question 53

Congenital Myopathy

Answer 53

A group of diseases including nemaline myopathy, central core myopathy, and centronuclear myopathy Results from abnormalities of sarcomeric proteins Characterized by weakness and mm atrophy that typically present at birth

Question 54

Mm, brain, and eye abnormalities

Answer 54

Fukuyama CMD Walker-Warburg syndrome Muscle-eye-brain disease

Question 55

SMA

Answer 55

Manifested by a loss of anterior horn cells Results in phenotypic spectrum of disease states that have been divided into three types based on a functional classification system

Question 56

Clinical Presentation SMA type 1

Answer 56

Mother complains of decreased fetal movement during her pregnancy At birth, the affected child is hypotonic and may have difficulty feeding Mm wasting often severe and spontaneous movements are infrequent and of small amplitude Head lag Landau drape over examiner's hand

Question 57

Clinical Presentation SMA type 2

Answer 57

Affects infants, but is more benign than type 1 Presentation later in the first year of life when child is not pulling to stand Characterized by weakness and wasting of extremities and trunk musculature Fasciculations are common Mini-polymyoclonus May learn to walk with bracing

Question 58

Clinical Presentation SMA type 3

Answer 58

Symptoms of progressive weakness, wasting, and fasciculations Age of presentation can vary from the toddler years into adulthood, the latter of which some would classify as type IV Proximal mm are usually involved first and because of age of presentation, this disease may be confused with the MDs Decreased DTRs Contractures unusual Progressive spinal deformities uncommon as long as child remains ambulatory Genetic testing will show a deletion of SMN gene on fifth chromosome

Question 59

Pts with DMD

Answer 59

Absent DTRs

Question 60

SMA Prognosis

Answer 60

Can be aided by a good developmental history Symptoms that begin prior to 2 years of age have a relatively poorer prognosis (amb til around 12) Symptoms after 2 years of age typically ambulate til 44

Question 61

CMTD

Answer 61

One of the most common inherited neurological disorders aka Hereditary Motor and Sensory Neuropathy (HMSN) or Peroneal muscular atrophy Primarily affect peripheral nerves

Question 62

CMT1

Answer 62

Caused by abnormalities in myelin sheath

Question 63

CMT1A

Answer 63

Autosomal dominant disease that results from duplication of gene on chromosome 17 PMP-22 important in myelin sheath

Question 64

CMTD Typical Presentation

Answer 64

Weakness of foot and lower leg mm Foot deformities - cavus or cavo-varus and hammertoes "Inverted champagne bottle" due to loss of mm bulk Later on may occur in hands, which can affect fine motor skills

Question 65

CMTD Strength Training

Answer 65

Most useful if it begins before nerve degeneration and mm weakness progression to the point of disability Low-impact or no-impact exercises recommended... Biking, swimming

Question 66

CMTD Increased Pressure and Callus Formation...

Answer 66

Lateral border of foot and heel | Head and base of 5th MT

Question 67

CMTD Shoes

Answer 67

High toe box to accommodate hammer/claw toes Orthotics can sometimes be used to accommodate pes cavus and equally distribute foot pressure AFO's can be used to maintain everyday mobility and prevent injury

Question 68

CMTD Thumb splints

Answer 68

Can help with hand weakness and loss of fine motor skills

Question 69

CMTD Assistive Device Use

Answer 69

Should be used before disability sets in because devices may prevent mm strain and reduce mm weakening

Question 70

Neuromm diseases include...

Answer 70

Disorders of motor nerve Disorders of NMJ Disorders of mm