Neuromuscular Disorders in Childhood Flashcards
What is the pathophysiology of SMA?
- Autosomal recessive
- SMN (Survival Motor Neuron) plays a role in the function of all cells, mediating the assembly of a set of proteins that associate with RNA
- Portion of their alpha motor neurons undergo apoptosis
SMA Type I (Werdnig - Hoffmann Disease)
- Noted within the first 3 months of life
- decreased fetal movement during her pregnancy.
- at birth, hypotonic
- may have difficulty feeding
- Muscle wasting is severe
- spontaneous movements are infrequent and small
- Presents with a head lag on pull to sit
- will drape over the examiner’s hand when a Landau is performed
SMA Type II
- Affects infants but is more benign than SMA type I
- Presentation is later in the first year of life when the child is not pulling to stand
- weakness and wasting of the extremities and trunk
- Fasciculations are common on examination of the tone in these patients
- Fine tremor when the child attempts to use the limbs
- Mini-polymyoclonus
- May learn to walk with bracing
SMA Type III (Kugelberg-Welander Disease)
- progressive weakness, wasting, fasiculations
- age of presentation: toddler years into adulthood (would be classified as type IV)
- proximal mm first
- may be confused with DMD due to age of presentation
- DTR are decreased
- contracutres are unusual
How is SMA Type III diagnosed?
- clinical picture
- diagnostic studies: electromyogram, muscle biopsy (show denervation) –> also for other types
- genetic testing: deletion of SMN gene on 5th chromosome
What is the progronosis of SMA?
- aided by good developmental history
- s/s that begin prior to age 2 have poorer prognosis; ambulation until 12 yrs
- s/s after 2 yrs: pts ambulate until 44 yrs of age
What is the treatment of SMA?
- maintenance of function and flexibility
- pts need to be braced while ambulating and for standing
- standers
Charcot-Marie-Tooth (CMT) Disease
- hereditary motor and sensory neuropathy
- slowly progressive
- affects peripheral nerves
- causes sensory loss, weakness, muscle wasting
- distal musculature of feet, lower legs, hands, forearms
Interventions for CMT
- PT: improve strength, ROM, and functional activities
- Orthotic assessment and Rx can improve gait and functional activities
- custom braces can help decrease energy expenditure
This deficit of DMD is not progressive and is not related to the severity of disease.
Cognitive deficit; Overall, pts are cognitively functional.
Common goals of treatment for pts w/ DMD (2):
Promote ambulation as long as possible, keep patients upright and vertical.
Medical treatment of DMD: ____ have been shown to increase strength & to improve function for 6 months to 2 years.
Glucocorticoid corticosteroids
Name other developing medical therapies for DMD (5):
Creatine monohydrate, gene therapy, cell therapy, mutation-specific medication, & dystrophin substitution
Spinal fixation recommended when scoliosis begins to progress rapidly and spinal curve exceeds ___ degrees.
30
Use of ____ ventilation at night assists with breathing & provides a rest for overworked respiratory muscles
Nasal positive pressure
Cardiac treatment for pts w/ DMD:
Regular cardiac echocardiogram (ECHO) & electrocardiogram (ECG or EKG) monitoring.
Cardiac medications for ____ may be necessary. Pts may need heart transplantation for ___ cardiomyopathy
arrhythmias, dilated
For pts w/ DMD, a GI specialist may be needed to monitor for (3):
constipation issues, intestinal pseudo-obstruction, weight gain prevention
Three phases of presentation in regards to mobility:
- Early or ambulatory stage
- Transitional phase during loss of ambulation
- Later wheelchair stage
Neuomuscular diseases encompass disorders whose primary pathology affects…..
any part of the motor unit from anterior horn cells to the muscle itself
Are neuromuscular diseases acquired or hereditary?
Both
What is the most common symptom involved with neuormuscluar diseases?
Weakness
What is muscular dystrophy?
A group of muscle diseases that are genetically determined
- Steadily progressive degenerative course
What is the classification of muscular dystrophy based on?
Gene deficiencies
What is spinal muscle atrophy (SMA)?
Neurogenic disorders whose underlying pathology affect sensory and spinal interneurons and as a result anterior horn cells
(Muscle wasting and the inability to control limbs)
In SMA, where is the pathology located?
The pathology is in the muscle.
Can consist of: Myopathy or dystrophy
What s motor neuropathy? Example?
- A group of neurogenic disorders whose underlying pathology affects the peripheral nerves
- Charcot-Marie-Tooth (CMT) disease (intrinsics and formation of foot affected)
What gender is affected by Duchenne Muscular Dystrophy (DMD)?
Male
- X-linked inheritance pattern
- Males inherit the disease from their asymptomatic mothers
How is DMD diagnosed?
Muscle biopsy
How does a child with DMD progress?
They become progressively weaker
What is the mechanism of injury for DMD?
Dystrophinopathy mutation in the gene coding for the protein dystrophin
(Dystrophin - a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane)
What are some ways to diagnose DMD?
- Clinical findings
- Laboratory studies
- EMG
- Muscle biopsy (Most objective)
- Genetic testing (Most objective)
Explain the pathophysiology of DMD.
- Dystrophin - a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane)
- Absence of dystrophin leads to a reduction in all of the dystrophin-associated proteins in the muscle cell membrane.
- Causes a disruption in the linkage between the subsarcolemma cytoskeleton and the extracellular matrix
Describe the clinical presentation of DMD.
- Symptoms between 2-5 years of age
- Symptoms may not be noticed for months or years, and the disease may be misdiagnosed for years
- Reluctance to walk or run at appropriate ages, falling, difficulty getting up off the floor, toe walking, clumsiness, and an increase in size of several groups of muscles
- Pseudohypertrophy in calves
What are 2 of the biggest obstacles for a patient with DMD?
climbing a step and running to do quad weakness
What 5 areas are examined to test functional abilities in DMD?
1) Stable performance or declining performance
2) Strength
3) pulmonary function (key)
4) functional tasks in combination
5) Times testing for monitoring function
What testing should be a routine part of PT in evaluation of the child with myopathy?
MMT
T/F: There is a correlation between rate of decline and use of wheelchair in DMD.
FALSE!
What systems have been used in attempts to better quantify muscle strength in boys with DMD?
Handheld myometry and various fixed tensiometer systems
ROM Measurement of these 3 areas in DMD are the most important aspects of goniometric testing.
ankle dorsiflexion, knee extension, and hip extension
What are the 8 main PT problems in DMD?
1) Weakness
2) Decreased active and passive ROM
3) Loss of ambulation
4) Decreased functional ability
5) Decreased pulmonary function
6) Emotional trauma—individual and family
7) Progressive scoliosis
8) Pain
In DMD, what are 7 main goals for PT?
1) Prevent deformity
2) Improve pulmonary function
3) Prolonging ambulation
4) Prolong functional capacity
5) Faciltate developmental assistance of family support & support of others
6) Control pain
7) ADLs
Avoidance of maximal ______ _____training and _____ exercise is recommended for boys with DMD.
resistive strength; eccentric
What type of exercise is recommended for boys with DMD?
Submaximal, endurance training such as swimming or cycling
Clinical Progression of DMD
- weakness steadily progressive
- Proximal muscles (quads) tend to be weaker earlier
- Lumbar lordosis
- Wide BOS
- Contracture development
- Slow functional activities
What is Gowers Sign
pushing self up with hands successively on the floor, knees and then thighs because of weakness in glutes
What develops as the age of the child with DMD increases
Scoliosis
At what age are scoliotic curves generally noticed
Not noticed until after 11 years of age
What happens to their respiratory system in those with DMD
- Respiratory musculatrue atrophies
- Coughing becomes ineffective
- Pulmonary infection more frequent
- Progressive weakness of muscles of respiration
- High degree of aspirating
What happends with the GI tract in those with DMD
- Muscle of GI tract are affected
- Causing constipation and risk of acute gastric dilation or intestinal pseudo-obstruction
- Sudden episodes of vomiting, ab pain, and distension
What are some Cardiac issues related to DMD
Deficiency of dystrophin resulting in cardimyopathy, arrhythmias, and CHF
-Heart muscle involvement ocurs later than skeletal muscle involvement
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