View source for Paralysis

{{Short description|Loss of motor function}}
{{Use American English|date=February 2024}}
{{Use mdy dates|date=February 2024}}
{{Redirect|Paralyzed|other uses|Paralysed (disambiguation)|and|Paralysis (disambiguation)}}
{{Redirect|Paralytic|the gene|Paralytic (gene)}}
{{Distinguish|Hemiparesis|Numbness|Spasticity|Sensory loss|Spastic hemiplegia}}
{{More citations needed|date=January 2020}}
{{Infobox medical condition (new)
| name            = Paralysis
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| caption         = [[Christopher Reeve]] who was paralyzed in an accident.
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| field           = [[Neurology]], [[neurosurgery]], [[psychiatry]]
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'''Paralysis''' ({{plural form}}: '''paralyses'''; also known as '''plegia''') is a loss of [[Motor skill|motor]] function in one or more [[Skeletal muscle|muscles]]. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the [[United States]], roughly 1 in 50 people have been diagnosed with some form of permanent or transient paralysis.<ref>{{Cite web |title=Paralysis Facts & Figures - Spinal Cord Injury - Paralysis Research Center |url=http://www.christopherreeve.org/site/c.mtKZKgMWKwG/b.5184189/k.5587/Paralysis_Facts__Figures.htm |url-status=dead |archive-url=https://web.archive.org/web/20160324021033/http://www.christopherreeve.org/site/c.mtKZKgMWKwG/b.5184189/k.5587/Paralysis_Facts__Figures.htm |archive-date=2016-03-24 |access-date=2013-02-19 |publisher=Christopherreeve.org}}</ref> The word "paralysis" derives from the [[Greek language|Greek]] παράλυσις, meaning "disabling of the nerves"<ref>{{Cite book |last1=Liddell |first1=Henry George |title=A Greek-English Lexicon |last2=Scott |first2=Robert |publisher=Clarendon Press |year=1940 |location=Oxford |chapter=παράλυσις |chapter-url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dpara%2Flusis}} on Perseus</ref> from παρά (''para'') meaning "beside, by"<ref>{{harvnb|Liddell|Scott|1940|loc=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dpara%2F παρά]}}</ref> and λύσις (''lysis'') meaning "making loose".<ref>{{harvnb|Liddell|Scott|1940|loc=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dlu%2Fsis λύσις]}}</ref> A paralysis accompanied by involuntary tremors is usually called "[[palsy]]".<ref>{{Cite web |title=Palsy |url=http://www.oxforddictionaries.com/definition/english/palsy |url-status=dead |archive-url=https://web.archive.org/web/20120724030627/http://oxforddictionaries.com/definition/english/palsy |archive-date=July 24, 2012 |access-date=27 May 2015 |publisher=[[Lexico]]}}</ref><ref>{{Cite encyclopedia |title=Palsy |encyclopedia=[[Merriam-Webster]] |url=http://www.merriam-webster.com/dictionary/palsy |access-date=27 May 2015}}</ref>

==Causes==
Paralysis is most often caused by damage in the [[nervous system]], especially the [[spinal cord]]. Other major causes are [[stroke]], [[Physical trauma|trauma]] with [[nerve injury]], [[poliomyelitis]], [[cerebral palsy]], [[peripheral neuropathy]], [[Parkinson's disease]], [[ALS]], [[botulism]], [[spina bifida]], [[multiple sclerosis]] and [[Guillain–Barré syndrome]]. Incidents that can cause such damage include [[Slip and fall|slip and fall accidents]], [[motor vehicle accidents]], [[Assault|assaults]], [[Gunshot wound|gunshot wounds]], industrial accidents and [[Sports injury|sports injuries]].<ref>{{Cite web |last= |first= |date=2024-04-23 |title=Causes of Catastrophic Paralysis Injuries |url=https://thetexaslawdog.com/blog/causes-of-catastrophic-paralysis-injuries/ |access-date=2025-05-27 |website=Aulsbrook |language=en}}</ref> Temporary paralysis occurs during [[REM sleep]], and dysregulation of this system can lead to episodes of [[sleep paralysis|waking paralysis]]. Drugs that interfere with [[action potential|nerve function]], such as [[curare]], can also cause paralysis.

''Pseudoparalysis'' (''pseudo-'' meaning "false, not genuine", from Greek ψεῦδος<ref>{{harvnb|Liddell|Scott|1940|loc=[https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3Dyeu%3Ddos ψεῦδος]}}</ref>) is voluntary restriction or inhibition of motion because of pain, incoordination, or other cause, and is not due to actual muscular paralysis.<ref>[http://medical-dictionary.thefreedictionary.com/pseudoparalysis TheFreeDictionary > pseudoparalysis], in turn citing The American Heritage Medical Dictionary 2007, 2004</ref> In an infant, it may be a symptom of [[congenital syphilis]].<ref>{{Cite journal |vauthors=Workowski KA, Berman SM |date=August 2006 |title=Sexually transmitted diseases treatment guidelines, 2006 |url=https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5511a1.htm |journal=MMWR Recomm Rep |volume=55 |issue=RR–11 |pages=1–94 |pmid=16888612 |quote=... evidence of congenital syphilis (e.g., nonimmune hydrops, jaundice, hepatosplenomegaly, rhinitis, skin rash, and/or pseudoparalysis of an extremity).}}</ref> Pseudoparalysis can be caused by extreme mental stress and is a common feature of mental disorders such as [[panic anxiety|panic anxiety disorder]].<ref>{{Cite web |title=anxiety-panic.com |url=http://anxiety-panic.com/dictionary/en-dictp.htm |url-status=dead |archive-url=https://web.archive.org/web/20180730202939/http://anxiety-panic.com/dictionary/en-dictp.htm |archive-date=2018-07-30 |access-date=2017-06-06 |website=anxiety-panic.com}}</ref>

==Variations==
Paralysis can occur in localized or generalized forms, or it may follow a certain pattern. Most paralyses caused by nervous-system damage (e.g., [[spinal cord injuries]]) are constant in nature; however, some forms of [[periodic paralysis]], including [[sleep paralysis]], are caused by other factors.<ref name="auto">{{Cite journal |last=Hutchinson |first=Jonathan |date=1877 |title=Clinical Lecture On Cases Of Spina Bifida, With Paralysis Of Sphincters |journal=The British Medical Journal |volume=1 |issue=830 |pages=767–768 |doi=10.1136/bmj.1.860.767 |jstor=25244879 |pmc=2220916 |pmid=20748563}}</ref>
<ref name="auto1">{{Cite book |last=Saladin |first=Kenneth |title=Anatomy and Physiology: Form and Function |date=2012 |publisher=McGraw Hill |isbn=978-0-07-337825-1}}</ref>

Paralysis can occur in newborns due to a [[Birth defect|congenital]] defect known as [[spina bifida]]. Spina bifida causes one or more of the vertebrae to fail to form vertebral arches within the infant, which allows the spinal cord to protrude from the rest of the spine. In extreme cases, this can cause spinal cord function inferior to the missing vertebral arches to cease.<ref name="auto1" /> This cessation of spinal cord function can result in paralysis of lower extremities. Documented cases of paralysis of the anal sphincter in newborns have been observed when spina bifida has gone untreated.<ref name="auto" /> While life-threatening, many cases of spina bifida can be corrected surgically if operated on within 72 hours of birth.

'''Ascending paralysis''' presents in the lower limbs before the upper limbs. It can be associated with:
* [[Guillain–Barré syndrome]] (another name for this condition is ''Landry's ascending paralysis'')
* [[Tick paralysis]]<ref>{{MedlinePlusEncyclopedia|001359|Tick paralysis}}</ref>

Ascending paralysis contrasts with '''descending paralysis''', which occurs in conditions such as [[botulism]].

==Other animals==
Many animal species use paralyzing toxins to capture prey, evade predation, or both. In stimulated muscles, the decrease in frequency of the miniature potentials runs parallel to the decrease in postsynaptic potential, and to the decrease in muscle contraction. In invertebrates, this clearly indicates that, e.g., ''[[Microbracon]]'' (wasp genus) venom causes paralysis of the neuromuscular system by acting at a presynaptic site. ''[[Philanthus]]'' venom inhibits both the fast and slow neuromuscular system at identical concentrations. It causes a decrease in the frequency of the miniature potentials without affecting their amplitude significantly.{{citation needed|date=July 2021}}

===Invertebrates===
In some species of [[wasp]], to complete the reproductive cycle, the female wasp paralyzes a prey item such as a grasshopper and places it in her nest. In the species ''[[Philanthus gibbosus]]'', the paralyzed insect (most often a bee species) is coated in a thick layer of pollen. The adult ''P. gibbosus'' then lays eggs in the paralyzed insect, which is devoured by the [[larva]]e when they hatch.<ref>{{Cite journal |last1=Colman |first1=D. R. |last2=Toolson |first2=E. C. |last3=Takacs-Vesbach |first3=C. D. |date=2012-10-01 |title=Do diet and taxonomy influence insect gut bacterial communities? |journal=Molecular Ecology |volume=21 |issue=20 |pages=5124–5137 |doi=10.1111/j.1365-294X.2012.05752.x |issn=1365-294X |pmid=22978555 |bibcode=2012MolEc..21.5124C |s2cid=23740875}}</ref>

===Vertebrates===
An example of a vertebrate-produced paralyzing toxin is the [[tetrodotoxin]] of fish species such as ''[[Takifugu rubripes]]'', the famously lethal [[pufferfish]] of Japanese [[fugu]], which works by binding to [[sodium channels]] in nerve cells, inhibiting the cells' proper function. A nonlethal dose of this toxin results in temporary paralysis. This toxin is also present in many other species ranging from toads to [[nemertea]]ns.<ref>{{Cite journal |last1=Noguchi |first1=Tamao |last2=Arakawa |first2=Osamu |date=2008-05-28 |title=Tetrodotoxin--distribution and accumulation in aquatic organisms, and cases of human intoxication |journal=Marine Drugs |volume=6 |issue=2 |pages=220–242 |doi=10.3390/md20080011 |doi-access=free |issn=1660-3397 |pmc=2525488 |pmid=18728726}}</ref>

Paralysis can be seen in breeds of dogs that are [[chondrodysplastic]].<ref>{{Cite web |last=Coile |first=Caroline |date=October 10, 2023 |title=Dog Paralysis: Everything You Need to Know About Causes & Treatments |url=https://www.akc.org/expert-advice/health/dog-paralysis-what-to-know/ |access-date=2025-05-27 |publisher=American Kennel Club |language=en}}</ref> 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 cut off circulation. If no signs of pain can be elicited, surgery should be performed within 24&nbsp;hours of the incident, to remove the disc material and relieve pressure on the [[spinal cord]]. After 24&nbsp;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.<ref>{{Cite web |title=Fibrocartilaginous Embolus/Emboli (FCE) in Dogs |url=https://vcahospitals.com/know-your-pet/fibrocartilaginous-embolusemboli-fce-in-dogs |access-date=2025-05-27 |website=Vca |language=en}}</ref>

The [[German Shepherd Dog]] 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. Affected dogs will become incontinent and gradually weaker in the hind legs as nerves die off. Eventually, their hind legs become useless.  This disease also affects other large breeds of dogs.<ref>{{Cite web |title=German Shepherd - Degenerative Myelopathy |url=https://www.ufaw.org.uk/dogs/german-shepherd-degenerative-myelopathy |access-date=2025-05-27 |website=www.ufaw.org.uk |language=english}}</ref> 

Cats with a [[heart murmur]] may develop blood clots that travel through arteries. If a 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.<ref>{{Cite web |title=Saddle Thrombus in Cats: Causes, Symptoms, and How To Help Your Cat |url=https://www.petmd.com/cat/conditions/cardiovascular/saddle-thrombus-cats-causes-symptoms-and-how-help-your-cat |access-date=2025-05-27 |website=www.petmd.com |language=en}}</ref>

Many snakes and trees exhibit powerful [[neurotoxins]] that can cause nonpermanent paralysis or death.<ref>{{Cite journal |last1=AlShammari |first1=Altaf K. |last2=Abd El-Aziz |first2=Tarek Mohamed |last3=Al-Sabi |first3=Ahmed |date=2023-12-25 |title=Snake Venom: A Promising Source of Neurotoxins Targeting Voltage-Gated Potassium Channels |journal=Toxins |volume=16 |issue=1 |pages=12 |doi=10.3390/toxins16010012 |doi-access=free |issn=2072-6651 |pmc=10820993 |pmid=38251229}}</ref>

==See also==
{{Colbegin|colwidth=15em}}
* [[Spinal cord injuries]]
* [[Paraplegia]]
* [[Quadriplegia]]
* [[Hemiparesis]]
* [[Monoplegia]]
* [[Muscle relaxant]]
* [[Beriberi]]
* [[Neuroprosthetics]]
* [[Brain–computer interface]]
* [[Tonic immobility]]
* [[Cerebral palsy]]
* [[Cobratoxin]]
* [[Obdormition]]
* [[Narcolepsy]]
* [[Cataplexy]]
*{{annotated link|Locked-in syndrome}}
{{colend}}

==References==
{{Reflist}}

==External links==
{{wiktionary-inline}}

{{Medical resources
| DiseasesDB     =
| ICD11          = {{ICD11|MB5Z}}
| ICD10          = {{ICD10|G83.9}}
| ICD9           = {{ICD9|359.3}}
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| OMIM           =
| MedlinePlus    =
| eMedicineSubj  =
| eMedicineTopic =
| MeshID         = D010243
}}

{{Authority control}}

[[Category:Nervous system]]
[[Category:Motor control]]
[[Category:Cerebral palsy and other paralytic syndromes]]
[[Category:Neurology]]