Infant Toddler Development Training
Module 6, Lesson 4
Muscle Diseases also known as Muscular Dystrophies
Some neurological disorders are related specifically to the atrophy or wasting away of the muscles due to processes in the muscles only. This is called muscular dystrophy. The two most common muscular dystrophies are Becker's and Duchenne's. The onset of Becker's type is later and the progression is slower than in Duchenne's. In both types, because of its x-linked inheritance, the incidence occurs only in males although the carrier is female. Usually, Duchenne's is diagnosed in boys ages 3 to 7 years. In a limited number of cases Duchenne's has been diagnosed in the toddler years. As a general rule, the earlier the diagnosis, the more severe and rapid the progression of the disease. Many boys who have Duchenne's are in wheelchairs by the age of ten years. Becker's, with its slower onset, is not usually diagnosed until around the age of 10 years.
The symptoms of muscular dystrophies include progressive and proximal muscle degeneration, muscle wasting, cardiomyopathy, and enlarged calves. The muscle wasting may result in scoliosis, congestive heart failure, and loss of ambulation. Treating with glucocorticosteroids sometimes prolongs the ability to ambulate.
Once the child is diagnosed, the family generally needs extensive support in dealing with grief. Mothers particularly may feel responsible, because they are carriers for the disorder, yet females themselves are protected because they have a normal "X" chromosome.
Consider how the ITDS may assist the family whose child has muscular dystrophy. What can you suggest?
Mitochrondrial Myopathies (MITO or MM)
Mitochrondrial myopathies are due to abnormal functioning of the mitochondria (energy producing cell structures) that results in muscle weakness. These myopathies have associated complications that can include seizures, sensory issues, diabetes, migraines, and cardiac disease.
Mitochondrial myopathies also referred to as MITO or MM may cause several problems in children. Problems include gastrointestinal problems that can result in inadequate nutrition. Other issues include epilepsy, drooping eyelids (ptosis) that can interfere with visual function, fatigue, and poor balance. Muscle weakness can result in respiratory problems and the child may require a ventilator to breathe. Some of the more common (though extremely rare) mitochrondrial myopathies are Kearns-Sayre syndrome, Leigh's syndrome, mitochondrial deletion syndrome (MDS), and mitochondrial encephalopathy.
As with all muscular dystrophies the main goals on an intervention plan would be to ensure
- full integration into the community
- maximization of functional capacities
- maintaining and prolonging function and locomotion
- decreasing or preventing a deformity
Go to Muscular Dystrophy Association of the USA. This is an excellent website that provides information about various muscular dystrophies including characteristics, age of onset, progression, treatments, teacher tips, and specialists who may become involved. The site includes the mitochondrial myopathies. Information can be found on the site both in English and Spanish. Specific pages that address the mitochondrial myopathies, issues and treatments are MDA USA Mitochondrial Myopathy and MDA USA Publication on MM .
Anterior Horn Cell
Peripheral nerves originate in anterior horn cells that control movement. When they degenerate there are motor deficits; yet the sensory functions may still be intact. One of the most famous of the anterior horn cell degenerative conditions is Amyotrophic Lateral Sclerosis (ALS also known as Lou Gehrig's Disease). The condition usually affects individuals much later in life; however, infants and toddlers may have anterior horn cell damage related to a myelomeningocele that will affect their motor abilities. Spinal muscular atrophy or Werdnig-Hoffmann Disease also involves anterior horn cell dysfunction. It is a congenital neuromuscular disorder associated with progressive muscular atrophy, weakness and loss of motor skills. Spinal muscular atrophy types 1 and 2 are autosomal recessive genetic conditions. Both are fatal conditions; although with good medical treatment and care persons who have type 2 can survive into the third decade of life.
Polio is a viral infection of the spinal cord that affects the anterior horn cells and causes an asymmetrical ascending paralysis. Polio, once common, is now almost eradicated worldwide due to vaccination.
Motor End Plate
The motor end plate of a nerve cell sends signals from the neuron to the associated skeletal muscle. Motor end plate diseases occur when there is a failure of motor nerve impulses to cross to the muscle end plate at the neuromuscular junction. It includes such diseases as infantile botulism, toxic-metabolic disturbances, and Myasthenia Gravis.
Myasthenia Gravis is characterized by progressive fatigue and weakening of the skeletal muscles caused by impaired transmission of nerve impulses caused by an autoimmune attack on nerve cells called acetylcholine receptors. The condition is very rare in children; although it can occur. The condition may show improvement with a medicine called mestinon or immune therapy as it is an autoimmune disorder.
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