Human Occ II: Chapter 27

Motor unit

-elementary functional unit in the motor system

-components are motor neurons and muscle fibers that it innervates

Diseases of muscular system

may be neurogenic (originating in the nerves) or myopathic (originating in the muscles)

Lesions can be caused by

-Infections

-Nerve root compression

-Toxins

-Neoplasms

-Vascular disorders

-Degenerative diseases of the CNS

-Congenital malformations

Medical treatment for polio

-Bed rest, positioning and applications of warm packs to reduce pain and promote relaxation

Postpolio Syndrome

Characterized by increased weakness of muscles that were previously affected by the polio infection

Guillain-Barre Syndrome (GBS)

-Is an acute inflammatory condition involving the spinal nerve roots, peripheral nerves, and in some cases cranial nerves

-Often follows a viral illness, immunizations, or surgery, and may affect both sexes at any age

Guillain-Barre Syndrome recovery rate

In many cases, the client completely recovers within a few weeks to a few months with relatively few residual side effects

OT intervention process for GBS

Initial phase focuses on PROM, positioning and splinting, then progresses to gentle/nonresistive activities like ADLs

Peripheral Nerve Injuries

-Peripheral nerve injury results in muscle weakness or flaccid paralysis

-Results in atrophy (loss of muscle innervation)

Nerve regeneration

Begins about 1 month after the injury, but depends on the nature of the nerve lesion

-Can regenerate .5" to 1" per month if the nerve root has been surgically repaired or cleanly severed

Regeneration rate

Proximal lesions regenerate faster than distal

Myasthenia gravis

-Disease of chemical transmission at the nerve-muscle synapse or neuromuscular junction

-Can affect any of the striated skeletal muscles of the body, but primarily targets muscles of the eyelids and eyes and oropharyngeal muscles (tongue, jaw and throat)

Muscular dystrophy (MD)

Progressive degeneration of muscle fibers with intact neuronal innervation and sensations

Duchenne MD

-Inherited as an X-linked recessive trait that affects only males and is usually diagnosed between 18 and 36 months

-Muscle weakness begins in the pelvic girdle and legs and then spreads to the shoulder girdle

-Most boys use a w/c by age of 12 for mobility and progresses to death, usually by the age of 30

Becker MD

presents with a later onset, slower course and far less predictability, and can affect girls

Facioscapulohumeral MD

-Onset in adolescence and affects muscles of face and shoulder girdle

-Does not shorten life expectancy

Myotonic MD

-Causes weakness and myotonia that makes relaxation of muscle contraction difficult

-Involves cranial muscles and shows a pattern of limb weakness that is distal rather than proximal

-GI, vision, heart, or respiration symptoms can also occur