::''Paralysed redirects here. For other uses see
Paralysed (disambiguation)''
'Paralysis' is the complete loss of
muscle function for one or more muscle groups. Paralysis often includes loss of feeling in the affected area.
Causes
Paralysis is most often caused by damage to the
nervous system or
brain, especially the
spinal cord. Partial paralysis can also occur in the
REM stage of sleep. Major causes are
stroke,
trauma,
poliomyelitis,
amyotrophic lateral sclerosis (ALS),
botulism,
spina bifida,
multiple sclerosis, and
Guillain-Barré syndrome.
Poisons that interfere with
nerve function, such as
curare, can also cause paralysis.
Variations
Paralysis may be localized, or generalized, or it may follow a certain pattern. For example, localized paralysis occurs in
Bell's palsy where one side of the face may be paralyzed due to inflammation of the
facial nerve on that side. Patients with
stroke may be weak throughout their body (global paralysis) or have
hemiplegia (weakness on one side of the body) or other patterns of paralysis depending on the area of damage in the brain. Other patterns of paralysis arise due to different
lesions and their
sequelae. For example, lower
spinal cord damage from a severe back injury may result in
paraplegia, while an injury higher up on the spinal cord, such as a neck injury, can cause
quadriplegia. Patients with
paraplegia or
quadriplegia often use equipment such as a
wheelchair or
standing frame for mobility and to regain some independence.
Most paralyses caused by nervous system damage are constant in nature; however, there are forms of
periodic paralysis, including
sleep paralysis, which are caused by other factors..
Paralysis in the celebrity world
Famous people with paralysis include the late
actor Christopher Reeve; film director
Michelangelo Antonioni; singer/songwriter
Curtis Mayfield; the architect
Michael Graves;
Sam Sullivan,
mayor of
Vancouver,
British Columbia,
Canada;
actor Jesse Billauer and
professional wrestling star
Hayabusa. American football legend
Nick Buoniconti, formerly of the
Miami Dolphins, is a staunch supporter of research to cure paralysis. His son, Marc Buoniconti, was paralyzed in a football game at the age of 19. The Buoniconti family funds The Miami Project to Cure Paralysis
[1] at the
University of Miami. Singer
Gloria Estefan was temporarily paralyzed after a traffic accident. After regaining mobility she became a supporter of The Miami Project.
Paralysis in the animal world
Many species of animals use paralyzing toxins in order to capture prey, evade predation, or both. One famous example is the
tetrodotoxin of fish species such as ''
Takifugu rubripes'', the famously lethal
pufferfish of Japanese
fugu. This toxin works by binding to
sodium channels in nerve cells, preventing the cells' proper function. A non-lethal dose of this toxin results in temporary paralysis. This toxin is also present in many other species ranging from toads to
nemerteans.
Another interesting use of paralysis in the natural world is the behavior of some species of
wasp. In order to complete the reproductive cycle, the female wasp first paralyzes a prey item such as a grasshopper and then places it into her nest. Eggs are then laid on the paralyzed insect, which is devoured by the
larvae after they hatch. Many snakes also exhibit powerful
neurotoxins that can cause non-permanent paralysis or
death.
Paralysis can be seen in breeds of dogs that are chondrodysplastic. These dogs have short legs, and may also have short muzzles. Their intervertebral disc material can calcify and become more brittle. In such cases, the disc may rupture, with disc material ending up in the spinal canal, or rupturing more laterally to press on spinal nerves. A minor rupture may only result in
paresis, but a major rupture can cause enough damage to result in complete paralysis. If no signs of pain can be elicited, surgery should be performed within 24 hours of the incident, to remove the disc material and relieve pressure on the
spinal cord. After 24 hours, the chance of recovery declines rapidly, since with continued pressure, the spinal cord tissue deteriorates and dies.
Another type of paralysis is caused by a fibrocartilaginous embolism. This is a microscopic piece of disc material that breaks off and becomes lodged in a spinal artery. Nerves served by the artery will die when deprived of blood.
The
German Shepherd is especially prone to developing degenerative
myelopathy. This is a deterioration of nerves in the spinal cord, starting in the posterior part of the cord. Dogs so affected will become gradually weaker in the hind legs as nerves die off. Eventually their hind legs become useless. They often also exhibit fecal and urinary incontinence. As the disease progresses, the paresis and paralysis gradually move forward. This disease also affects other large breeds of dogs. It is suspected to be an autoimmune problem.
Cats with
heart murmurs may develop blood clots which travel through arteries. If the clot is large enough to block one or both femoral arteries, there may be hind leg paralysis because the major source of blood flow to the hind leg is blocked.
See also
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Spinal cord injury
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Paraplegia
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Quadriplegia
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Muscle relaxant
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Ptosis
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Sleep paralysis
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Hemiparesis
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Beriberi
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Neuroprosthetics
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Brain-computer interface
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Tonic immobility
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Cerebral palsy
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Cobra Toxin