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{{short description|Any neurological disease in which the myelin sheath of neurons is damaged}}
{{short description|Any neurological disease in which the myelin sheath of neurons is damaged}}
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{{Infobox medical condition (new)
{{Infobox medical condition (new)
| name = Demyelinating disease
| name = Demyelinating disease
| image = MS Demyelinisation CD68 10xv2.jpg
| image = MS Demyelinisation CD68 10xv2.jpg
| caption = Photomicrograph of a demyelinating MS-lesion: [[Immunohistochemistry|Immunohistochemical staining]] for CD68 highlights numerous macrophages (brown). Original magnification 10×.
| caption = Photomicrograph of a demyelinating MS-lesion: [[Immunohistochemistry|Immunohistochemical staining]] for CD68 highlights numerous macrophages (brown). Original magnification 10×.
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A '''demyelinating disease''' is any [[disease]] of the [[nervous system]] in which the [[myelin]] sheath of [[neuron]]s is damaged.<ref>{{DorlandsDict|three/000030717|demyelinating disease}}</ref> This damage impairs the conduction of signals in the affected nerves. In turn, the reduction in conduction ability causes deficiency in sensation, movement, cognition, or other functions depending on which nerves are involved.
A '''demyelinating disease''' refers to any [[disease]] affecting the [[nervous system]] where the [[myelin sheath]] surrounding [[neurons]] is damaged.<ref>{{DorlandsDict|three/000030717|demyelinating disease}}</ref> This damage disrupts the transmission of signals through the affected nerves, resulting in a decrease in their conduction ability. Consequently, this reduction in conduction can lead to deficiencies in sensation, movement, cognition, or other functions depending on the nerves affected.


Demyelinating diseases can be caused by [[genetics]], [[infection|infectious]] agents, [[autoimmune disorder|autoimmune]] reactions, and other unknown factors. Proposed causes for demyelination include genetics and environmental factors such as being triggered by a viral infection or chemical exposure. [[Organophosphate]] poisoning by commercial insecticides such as [[sheep dip]], [[herbicide|weed killers]], and flea treatment preparations for pets, can also result in nerve demyelination.<ref name="pmid16042503">{{cite journal| author=Lotti M, Moretto A| title=Organophosphate-induced delayed polyneuropathy. | journal=Toxicol Rev | year= 2005 | volume= 24 | issue= 1 | pages= 37–49 | pmid=16042503 | doi= 10.2165/00139709-200524010-00003}}</ref> Chronic [[neuroleptic]] exposure may cause demyelination.<ref>{{cite journal |author=Konopaske GT |title=Effect of chronic antipsychotic exposure on astrocyte and oligodendrocyte numbers in macaque monkeys |journal=Biol. Psychiatry |volume=63 |issue=8 |pages=759–65 |date=April 2008 |pmid=17945195 |pmc=2386415 |doi=10.1016/j.biopsych.2007.08.018 |author2=Dorph-Petersen KA |author3=Sweet RA |display-authors=etal }}</ref> [[Vitamin B12|Vitamin B<sub>12</sub>]] deficiency may also result in dysmyelination.<ref name="pmid23984056">{{cite journal| author=Agadi S, Quach MM, Haneef Z| title=Vitamin-responsive epileptic encephalopathies in children.|journal=Epilepsy Res Treat|year= 2013|volume= 2013|pages= 510529|pmid=23984056|doi=10.1155/2013/510529|pmc=3745849}}</ref><ref name="pmid29675077">{{cite journal| author=Yoganathan S, Varman M, Oommen SP, Thomas M| title=A Tale of Treatable Infantile Neuroregression and Diagnostic Dilemma with Glutaric Aciduria Type I.|journal=J Pediatr Neurosci|year= 2017|volume= 12|issue= 4|pages= 356–359|pmid=29675077|doi=10.4103/jpn.JPN_35_17|pmc=5890558}}</ref>
Various factors can contribute to the development of demyelinating diseases, including [[genetic predisposition]], [[infectious]] agents, [[autoimmune reaction]]s, and other unknown factors. Proposed causes of demyelination include genetic predisposition, environmental factors such as viral infections or exposure to certain chemicals. Additionally, exposure to commercial insecticides like [[sheep dip]], [[Herbicide|weed killers]], and flea treatment preparations for pets, which contain [[organophosphates]], can also lead to nerve demyelination.<ref name="pmid16042503">{{cite journal |vauthors=Lotti M, Moretto A |title=Organophosphate-induced delayed polyneuropathy |journal=Toxicol Rev |volume=24 |issue=1 |pages=37–49 |date=2005 |pmid=16042503 |doi=10.2165/00139709-200524010-00003 |s2cid=29313644}}</ref> Chronic exposure to [[neuroleptic]] medications may also cause demyelination.<ref name="pmid17945195">{{cite journal |vauthors=Konopaske GT, Dorph-Petersen KA, Sweet RA, Pierri JN, Zhang W, Sampson AR, Lewis DA |title=Effect of chronic antipsychotic exposure on astrocyte and oligodendrocyte numbers in macaque monkeys |journal=Biol Psychiatry |volume=63 |issue=8 |pages=759–65 |date=April 2008 |pmid=17945195 |pmc=2386415 |doi=10.1016/j.biopsych.2007.08.018}}</ref> Furthermore, deficiencies in [[vitamin B12]] can result in dysmyelination.<ref name="pmid23984056">{{cite journal |vauthors=Agadi S, Quach MM, Haneef Z |date=2013 |title=Vitamin-responsive epileptic encephalopathies in children |journal=Epilepsy Res Treat |volume=2013 |issue= |pages=510529 |doi=10.1155/2013/510529 |pmc=3745849 |pmid=23984056 |doi-access=free}}</ref><ref name="pmid29675077">{{cite journal |vauthors=Yoganathan S, Varman M, Oommen SP, Thomas M |date=2017 |title=A Tale of Treatable Infantile Neuroregression and Diagnostic Dilemma with Glutaric Aciduria Type I |journal=J Pediatr Neurosci |volume=12 |issue=4 |pages=356–359 |doi=10.4103/jpn.JPN_35_17 |pmc=5890558 |pmid=29675077 |doi-access=free }}</ref>


Demyelinating diseases are traditionally classified in two kinds: '''demyelinating myelinoclastic diseases''' and '''demyelinating leukodystrophic diseases'''. In the first group, a normal and healthy myelin is destroyed by a toxic, chemical, or autoimmune substance. In the second group, myelin is abnormal and degenerates.<ref>{{cite journal |author1=Fernández O. |author2=Fernández V.E. |author3=Guerrero M. | year = 2015 | title = Demyelinating diseases of the central nervous system | journal = Medicine | volume = 11 | issue = 77| pages = 4601–4609 | doi = 10.1016/j.med.2015.04.001 }}</ref> The second group was denominated '''dysmyelinating diseases''' by [[Poser criteria|Poser]].<ref>{{cite journal | author = Poser C. M. | year = 1961 | title = Leukodystrophy and the Concept of Dysmyelination | journal = Arch Neurol | volume = 4 | issue = 3| pages = 323–332 | doi = 10.1001/archneur.1961.00450090089013 | pmid = 13737358 }}</ref>
Demyelinating diseases are traditionally classified into two types: '''demyelinating myelinoclastic diseases''' and '''demyelinating leukodystrophic diseases'''. In the first group, a healthy and normal myelin is destroyed by toxic substances, chemicals, or autoimmune reactions. In the second group, the myelin is inherently abnormal and undergoes degeneration.<ref>{{cite journal |vauthors=Fernández O,Fernández VE, Guerrero M |year=2015 |title=Demyelinating diseases of the central nervous system |journal=Medicine |volume=11 |issue=77 |pages=4601–4609 |doi=10.1016/j.med.2015.04.001}}</ref> The [[Poser criteria]] named this second group dysmyelinating diseases.<ref name="pmid13737358">{{cite journal |vauthors=POSER CM |title=Leukodystrophy and the concept of dysmyelination |journal=Arch Neurol |volume=4 |issue=3 |pages=323–32 |date=March 1961 |pmid=13737358 |doi=10.1001/archneur.1961.00450090089013}}</ref>


In the most well known example of demyelinating disease, [[multiple sclerosis]], evidence has shown that the body's own immune system is at least partially responsible. [[Acquired immune system]] cells called [[T-cells]] are known to be present at the site of lesions. Other immune-system cells called [[macrophages]] (and possibly [[mast cells]]) also contribute to the damage.<ref>{{cite web |author=Laetoli |title=Demyelination |date=January 2008 |url=http://www.mult-sclerosis.org/demyelination.html |url-status=live |archive-url=https://web.archive.org/web/20120728141709/http://www.mult-sclerosis.org/demyelination.html |archive-date=2012-07-28 }}</ref>
In the most well-known demyelinating disease, [[multiple sclerosis]], evidence suggests that the body's immune system plays a significant role. [[Acquired immune system]] cells, specifically [[T-cells]], are found at the site of lesions. Other immune system cells, such as [[macrophages]] (and possibly [[mast cells]]), also contribute to the damage.<ref>{{cite web |author=Laetoli |title=Demyelination |date=January 2008 |url=http://www.mult-sclerosis.org/demyelination.html |url-status=live |archive-url=https://web.archive.org/web/20120728141709/http://www.mult-sclerosis.org/demyelination.html |archive-date=2012-07-28}}</ref>


== Signs and symptoms ==
== Signs and symptoms ==
Symptoms and signs that present in demyelinating diseases are different for each condition. These symptoms and signs can present in a person with a demyelinating disease:<ref>"Symptoms of Demyelinating Disorders - Right Diagnosis." Right Diagnosis. Right Diagnosis, 01 Feb 2012. Web. 24 Sep 2012</ref>
Symptoms and signs that present in demyelinating diseases are different for each condition. These symptoms and signs can present in a person with a demyelinating disease:<ref>"Symptoms of Demyelinating Disorders - Right Diagnosis." Right Diagnosis. Right Diagnosis, 01 Feb 2012. Web. 24 Sep 2012</ref>


{{div col}}
<div align="center">
* Blurred double vision ([[Diplopia]])
{| align="left" summary="first column is left column"
|-
| align="left" |
* Blurred double vision (Diplopia)
* [[Ataxia]]
* [[Ataxia]]
* [[Clonus]]
* [[Clonus]]
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* Incoordination
* Incoordination
* [[Paresthesias]]
* [[Paresthesias]]
|}
{| summary="middle column visually second"
|-
| align="left" |
* Ocular paralysis (cranial nerve palsy)
* Ocular paralysis (cranial nerve palsy)
* Impaired muscle coordination
* Impaired muscle coordination
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* Loss of sensation
* Loss of sensation
* Impaired vision
* Impaired vision
* Neurological symptoms
* Unsteady gait
* Unsteady gait
* Spastic [[paraparesis]]
* Spastic [[paraparesis]]
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* Hearing problems
* Hearing problems
* Speech problems
* Speech problems
{{div col end}}
|}</div>


== Evolutionary considerations ==
== Evolutionary considerations ==
The role of prolonged cortical myelination in human evolution has been implicated as a contributing factor in some cases of demyelinating disease. Unlike other primates, humans exhibit a unique pattern of postpubertal myelination, which may contribute to the development of psychiatric disorders and neurodegenerative diseases that present in early adulthood and beyond. The extended period of cortical myelination in humans may allow greater opportunity for disruption in myelination, resulting in the onset of demyelinating disease.<ref>{{cite journal | author = Miller Daniel J | year = 2012 | title = Prolonged Myelination in Human Neocortical Evolution | doi = 10.1073/pnas.1117943109 | journal = PNAS | volume = 109 | issue = 41| pages = 16480–16485 | pmid=23012402 | pmc=3478650| bibcode = 2012PNAS..10916480M }}</ref> Furthermore, humans have significantly greater prefrontal white matter volume than other primate species, which implies greater myelin density.<ref>{{cite journal | author = Schoenemann, Thomas P. | author2 = Sheehan Michael J. | author3 = Glotzer L. Daniel | year = 2005 | title = Prefrontal White Matter Volume Is Disproportionately Larger in Humans than in Other Primates | journal = Nature Neuroscience | volume = 8 | issue = 2| pages = 242–52 | doi=10.1038/nn1394| pmid = 15665874 }}</ref> Increased myelin density in humans as a result of a prolonged myelination may, therefore, structure risk for myelin degeneration and dysfunction. Evolutionary considerations for the role of prolonged cortical myelination as a risk factor for demyelinating disease are particularly pertinent given that genetics and autoimmune deficiency hypotheses fail to explain many cases of demyelinating disease. As has been argued, diseases such as multiple sclerosis cannot be accounted for by autoimmune deficiency alone, but strongly imply the influence of flawed developmental processes in disease pathogenesis.<ref>{{cite journal | author = Chaudhuri Abhijit | year = 2013 | title = Multiple Sclerosis Is Primarily a Neurodegenerative Disease | journal = J Neural Transm | volume = 120 | issue = 10| pages = 1463–466 | doi=10.1007/s00702-013-1080-3| pmid = 23982272 }}</ref> Therefore, the role of the human-specific prolonged period of cortical myelination is an important evolutionary consideration in the pathogenesis of demyelinating disease.
The role of prolonged cortical myelination in human evolution has been implicated as a contributing factor in some cases of demyelinating disease. Unlike other primates, humans exhibit a unique pattern of postpubertal myelination, which may contribute to the development of psychiatric disorders and neurodegenerative diseases that present in early adulthood and beyond. The extended period of cortical myelination in humans may allow greater opportunities for disruption in myelination, resulting in the onset of demyelinating disease.<ref name="pmid23012402">{{cite journal |vauthors=Miller DJ, Duka T, Stimpson CD, Schapiro SJ, Baze WB, McArthur MJ, Fobbs AJ, Sousa AM, Sestan N, Wildman DE, Lipovich L, Kuzawa CW, Hof PR, Sherwood CC |title=Prolonged myelination in human neocortical evolution |journal=Proc Natl Acad Sci U S A |volume=109 |issue=41 |pages=16480–5 |date=October 2012 |pmid=23012402 |pmc=3478650 |doi=10.1073/pnas.1117943109 |bibcode=2012PNAS..10916480M |doi-access=free}}</ref> Furthermore, humans have significantly greater prefrontal white matter volume than other primate species, which implies greater myelin density.<ref name="pmid15665874">{{cite journal |vauthors=Schoenemann PT, Sheehan MJ, Glotzer LD |title=Prefrontal white matter volume is disproportionately larger in humans than in other primates |journal=Nat Neurosci |volume=8 |issue=2 |pages=242–52 |date=February 2005 |pmid=15665874 |doi=10.1038/nn1394 |s2cid=205430527}}</ref> Increased myelin density in humans as a result of a prolonged myelination may, therefore, structure risk for myelin degeneration and dysfunction. Evolutionary considerations for the role of prolonged cortical myelination as a risk factor for demyelinating disease are particularly pertinent given that genetics and autoimmune deficiency hypotheses fail to explain many cases of demyelinating disease. As has been argued, diseases such as multiple sclerosis cannot be accounted for by autoimmune deficiency alone, but strongly imply the influence of flawed developmental processes in disease pathogenesis.<ref name="pmid23982272">{{cite journal |vauthors=Chaudhuri A |title=Multiple sclerosis is primarily a neurodegenerative disease |journal=J Neural Transm (Vienna) |volume=120 |issue=10 |pages=1463–6 |date=October 2013 |pmid=23982272 |doi=10.1007/s00702-013-1080-3 |s2cid=8575687}}</ref> Therefore, the role of the human-specific prolonged period of cortical myelination is an important evolutionary consideration in the pathogenesis of demyelinating disease.{{citation needed|date=December 2021}}


== Diagnosis ==
== Diagnosis ==
Various methods/techniques are used to diagnose demyelinating diseases:
Various methods/techniques are used to diagnose demyelinating diseases:
* Exclusion of other conditions that have overlapping symptoms<ref name="Freedman">{{cite book|last=Freedman|first=Mark S|title=Advances in Neurology Volume 98: Multiple Sclerosis and Demyelinating Diseases |year=2005|publisher=Lippincott Williams & Wilkins |location=Philadelphia|isbn=0781751705|page=112}}</ref>
* Exclusion of other conditions that have overlapping symptoms<ref name="Freedman">{{cite book |vauthors=Freedman MS |title=Advances in Neurology Volume 98: Multiple Sclerosis and Demyelinating Diseases |year=2005 |publisher=Lippincott Williams & Wilkins |location=Philadelphia |isbn=0781751705 |page=112}}</ref>
* [[Magnetic resonance imaging]] (MRI) is a [[medical imaging]] technique used in [[radiology]] to visualize internal structures of the body in detail. MRI makes use of the property of [[nuclear magnetic resonance]] (NMR) to image nuclei of atoms inside the body. This method is reliable because MRIs assess changes in proton density. "Spots" can occur as a result of changes in brain water content.<ref name="Freedman"/>{{rp|113}}
* [[Magnetic resonance imaging]] (MRI) is a [[medical imaging]] technique used in [[radiology]] to visualize internal structures of the body in detail. MRI makes use of the property of [[nuclear magnetic resonance]] (NMR) to image nuclei of atoms inside the body. This method is reliable because MRIs assess changes in proton density. "Spots" can occur as a result of changes in brain water content.<ref name="Freedman"/>{{rp|113}}
* [[Evoked potential]] is an [[electrical potential]] recorded from the nervous system following the presentation of a stimulus as detected by [[electroencephalography]] (EEG), [[electromyography]] (EMG), or other electrophysiological recording method.<ref name="Freedman"/>{{rp|117}}
* [[Evoked potential]] is an [[electrical potential]] recorded from the nervous system following the presentation of a stimulus as detected by [[electroencephalography]] (EEG), [[electromyography]] (EMG), or other electrophysiological recording method.<ref name="Freedman"/>{{rp|117}}
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====CNS====
====CNS====
The demyelinating disorders of the [[central nervous system]] include:{{citation needed|date=August 2021}}

The demyelinating disorders of the [[central nervous system]] include:

* Myelinoclastic or demyelinating disorders:
* Myelinoclastic or demyelinating disorders:
** Typical forms of [[multiple sclerosis]]
** Typical forms of [[multiple sclerosis]]
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====PNS====
====PNS====
[[File:Guillain-barré syndrome - Nerve Damage.gif|thumb|Guillain–Barré syndrome – demyelination]]
[[File:Guillain-barré syndrome - Nerve Damage.gif|thumb|Guillain–Barré syndrome – demyelination]]
The demyelinating diseases of the [[peripheral nervous system]] include:
The demyelinating diseases of the [[peripheral nervous system]] include:{{citation needed|date=August 2021}}

* [[Guillain–Barré syndrome]] and its chronic counterpart, [[chronic inflammatory demyelinating polyneuropathy]]
* [[Guillain–Barré syndrome]] and its chronic counterpart, [[chronic inflammatory demyelinating polyneuropathy]]
* [[Anti-MAG peripheral neuropathy]]
* [[Anti-MAG peripheral neuropathy]]
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== Prognosis ==
== Prognosis ==
Prognosis depends on the condition itself. Some conditions such as MS depend on the subtype of the disease and various attributes of the patient such as age, sex, initial symptoms, and the degree of disability the patient experiences.<ref>{{cite journal|author=Weinshenker BG|title=Natural history of multiple sclerosis|journal=Ann. Neurol.|volume=36|issue=Suppl|pages=S6–11|year=1994 |doi=10.1002/ana.410360704|pmid=8017890}}</ref> Life expectancy in MS patients is 5 to 10 years lower than unaffected people.<ref name="Compston2008">{{cite journal |vauthors=Compston A, Coles A |title=Multiple sclerosis |journal=Lancet |volume=372 |issue=9648 |pages=1502–17 |date=October 2008 |doi=10.1016/S0140-6736(08)61620-7 |pmid=18970977}}</ref> MS is an inflammatory demyelinating disease of the
Prognosis depends on the condition itself. Some conditions such as MS depend on the subtype of the disease and various attributes of the patient such as age, sex, initial symptoms, and the degree of disability the patient experiences.<ref name="pmid8017890">{{cite journal |vauthors=Weinshenker BG |title=Natural history of multiple sclerosis |journal=Ann Neurol |volume=36 Suppl |issue= |pages=S6–11 |date=1994 |pmid=8017890 |doi=10.1002/ana.410360704 |s2cid=7140070}}</ref> Life expectancy in MS patients is 5 to 10 years lower than unaffected people.<ref name="Compston2008">{{cite journal |vauthors=Compston A, Coles A |title=Multiple sclerosis |journal=Lancet |volume=372 |issue=9648 |pages=1502–17 |date=October 2008 |doi=10.1016/S0140-6736(08)61620-7 |pmid=18970977 |s2cid=195686659}}</ref> MS is an inflammatory demyelinating disease of the central nervous system (CNS) that develops in genetically susceptible individuals after exposure to unknown environmental trigger(s). The bases for MS are unknown but are strongly suspected to involve immune reactions against autoantigens, particularly myelin proteins. The most accepted hypothesis is that dialogue between T-cell receptors and myelin antigens leads to an immune attack on the myelin-oligodendrocyte complex. These interactions between active T cells and myelin antigens provoke a massive destructive inflammatory response and promote continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators.<ref name="pmid14664465">{{cite journal |vauthors=Minagar A, Alexander JS |title=Blood-brain barrier disruption in multiple sclerosis |journal=Mult Scler |volume=9 |issue=6 |pages=540–9 |date=December 2003 |pmid=14664465 |doi=10.1191/1352458503ms965oa |s2cid=10189144}}</ref> Other conditions such as [[central pontine myelinolysis]] have about a third of patients recover and the other two-thirds experience varying degrees of disability.<ref name="pmid16210283">{{cite journal |vauthors=Abbott R, Silber E, Felber J, Ekpo E |title=Osmotic demyelination syndrome |journal=BMJ |volume=331 |issue=7520 |pages=829–30 |date=October 2005 |pmid=16210283 |pmc=1246086 |doi=10.1136/bmj.331.7520.829}}</ref> In some cases, such as [[transverse myelitis]], the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition.{{citation needed|date=August 2021}}
central nervous system (CNS) that develops in genetically susceptible individuals after exposure to unknown environmental trigger(s). The bases for MS are unknown but are strongly suspected to involve immune reactions against autoantigens, particularly myelin proteins. The most accepted hypothesis is that dialogue between T-cell receptors and myelin antigens leads to an immune attack on the myelin-oligodendrocyte complex. These interactions between active T cells and myelin antigens provoke a massive destructive inflammatory response and promote continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators.<ref>{{cite journal|last=Minegar|first=Alireza|title=Blood-Brain Barrier Disruption in Multiple Sclerosis|journal=Multiple Sclerosis Journal|volume=9|issue=6|pages=540–549|publisher=Sage Journals|doi=10.1191/1352458503ms965oa|pmid=14664465|year=2003}}</ref> Other conditions such as [[central pontine myelinolysis]] have about a third of patients recover and the other two-thirds experience varying degrees of disability.<ref name="pmid16210283">{{cite journal |vauthors=Abbott R, Silber E, Felber J, Ekpo E |title=Osmotic demyelination syndrome |journal=BMJ |volume=331 |issue=7520 |pages=829–30 |date=October 2005 |pmc=1246086 |doi=10.1136/bmj.331.7520.829 |pmid=16210283}}</ref> In some cases, such as [[transverse myelitis]], the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition.


== Epidemiology ==
== Epidemiology ==
Incidence of demyelinating diseases varies by disorder. Some conditions, such as [[tabes dorsalis]] appear predominantly in males and begin in midlife. [[Optic neuritis]], though, occurs preferentially in females typically between the ages of 30 and 35.<ref>{{cite journal |vauthors=Rodriguez M, Siva A, Cross SA, O'Brien PC, Kurland LT |title=Optic neuritis: a population-based study in Olmsted County, Minnesota |journal=Neurology |volume=45 |issue=2 |pages=244–50 |year=1995 |pmid=7854520 |doi=10.1212/WNL.45.2.244}}</ref> Other conditions such as multiple sclerosis vary in prevalence depending on the country and population.<ref>{{cite journal|author=Rosati G|title=The prevalence of multiple sclerosis in the world: an update|journal=Neurol. Sci.|volume=22|issue=2|pages=117–39|date=April 2001|doi=10.1007/s100720170011|pmid=11603614}}</ref> This condition can appear in children and adults.<ref name="Compston2008" />
Incidence of demyelinating diseases varies by disorder. Some conditions, such as [[tabes dorsalis]] appear predominantly in males and begin in midlife. [[Optic neuritis]], though, occurs preferentially in females typically between the ages of 30 and 35.<ref name="pmid7854520">{{cite journal |vauthors=Rodriguez M, Siva A, Cross SA, O'Brien PC, Kurland LT |title=Optic neuritis: a population-based study in Olmsted County, Minnesota |journal=Neurology |volume=45 |issue=2 |pages=244–50 |date=February 1995 |pmid=7854520 |doi=10.1212/wnl.45.2.244 |s2cid=25800388}}</ref> Other conditions such as multiple sclerosis vary in prevalence depending on the country and population.<ref name="pmid11603614">{{cite journal |vauthors=Rosati G |title=The prevalence of multiple sclerosis in the world: an update |journal=Neurol Sci |volume=22 |issue=2 |pages=117–39 |date=April 2001 |pmid=11603614 |doi=10.1007/s100720170011 |s2cid=207051545}}</ref> This condition can appear in children and adults.<ref name="Compston2008" />


== Research ==
== Research ==
Much of the research conducted on demyelinating diseases is targeted towards discovering the mechanisms by which these disorders function in an attempt to develop therapies and treatments for individuals affected by these conditions. For example, [[proteomics]] has revealed several proteins which contribute to the pathophysiology of demyelinating diseases.<ref>{{cite journal|author= Newcombe, J.|last2=Eriksson|first2=B.|last3=Ottervald|first3=J.|last4=Yang|first4=Y.|last5=Franzen|first5=B. |title= Extraction and proteomic analysis of proteins from normal and multiple sclerosis postmortem brain|journal= Journal of Chromatography B |volume= 815|issue= 1–2|pages=119–202|year=2005 |doi= 10.1016/j.jchromb.2004.10.073|pmid=15652809}}</ref>
Much of the research conducted on demyelinating diseases is targeted towards discovering the mechanisms by which these disorders function in an attempt to develop therapies and treatments for individuals affected by these conditions. For example, [[proteomics]] has revealed several proteins which contribute to the pathophysiology of demyelinating diseases.<ref name="pmid15652809">{{cite journal |vauthors=Newcombe J, Eriksson B, Ottervald J, Yang Y, Franzén B |title=Extraction and proteomic analysis of proteins from normal and multiple sclerosis postmortem brain |journal=J Chromatogr B Analyt Technol Biomed Life Sci |volume=815 |issue=1–2 |pages=191–202 |date=February 2005 |pmid=15652809 |doi=10.1016/j.jchromb.2004.10.073}}</ref>
For example, [[Prostaglandin-endoperoxide synthase 2|COX-2]] has been implicated in [[oligodendrocyte]] death in animal models of demyelination.<ref name="pmid21699540">{{cite journal |vauthors=Palumbo S, Toscano CD, Parente L, Weigert R, Bosetti F |title=The cyclooxygenase-2 pathway via the PGE₂ EP2 receptor contributes to oligodendrocytes apoptosis in cuprizone-induced demyelination |journal=J Neurochem |volume=121 |issue=3 |pages=418–27 |date=May 2012 |pmid=21699540 |pmc=3220805 |doi=10.1111/j.1471-4159.2011.07363.x}}</ref>
The presence of myelin debris has been correlated with damaging inflammation as well as poor regeneration, due to the presence of inhibitory myelin components.<ref name="pmid22689449">{{cite journal |vauthors=Clarner T, Diederichs F, Berger K, Denecke B, Gan L, van der Valk P, Beyer C, Amor S, Kipp M |title=Myelin debris regulates inflammatory responses in an experimental demyelination animal model and multiple sclerosis lesions |journal=Glia |volume=60 |issue=10 |pages=1468–80 |date=October 2012 |pmid=22689449 |doi=10.1002/glia.22367 |s2cid=205834726}}</ref><ref name="pmid24961530">{{cite journal |vauthors=Podbielska M, Banik NL, Kurowska E, Hogan EL |title=Myelin recovery in multiple sclerosis: the challenge of remyelination |journal=Brain Sci |volume=3 |issue=4 |pages=1282–324 |date=August 2013 |pmid=24961530 |pmc=4061877 |doi=10.3390/brainsci3031282 |doi-access=free}}</ref>


[[N-cadherin]] is expressed in regions of active remyelination and may play an important role in generating a local environment conducive to remyelination.<ref name="pmid22735489">{{cite journal |vauthors=Hochmeister S, Romauch M, Bauer J, Seifert-Held T, Weissert R, Linington C, Hartung HP, Fazekas F, Storch MK |title=Re-expression of N-cadherin in remyelinating lesions of experimental inflammatory demyelination |journal=Exp Neurol |volume=237 |issue=1 |pages=70–7 |date=September 2012 |pmid=22735489 |doi=10.1016/j.expneurol.2012.06.010 |s2cid=33883037}}</ref> N-cadherin [[agonist]]s have been identified and observed to stimulate [[neurite]] growth and cell migration, key aspects of promoting axon growth and remyelination after injury or disease.<ref name="pmid20153391">{{cite journal |vauthors=Burden-Gulley SM, Gates TJ, Craig SE, Gupta M, Brady-Kalnay SM |title=Stimulation of N-cadherin-dependent neurite outgrowth by small molecule peptide mimetic agonists of the N-cadherin HAV motif |journal=Peptides |volume=31 |issue=5 |pages=842–9 |date=May 2010 |pmid=20153391 |doi=10.1016/j.peptides.2010.02.002 |s2cid=207357858}}</ref>
For example, [[Prostaglandin-endoperoxide synthase 2|COX-2]] has been implicated in [[oligodendrocyte]] death in animal models of demyelination.<ref>{{cite journal|author= Palumbo, S.|last2=Toscano|first2=C.D.|last3=Parente|first3=L.|last4=Weigert|first4=R.|last5=Bosetti|first5=F. |title= The cyclooxygenase-2 pathway via the pge₂ ep2 receptor contributes to oligodendrocytes apoptosis in cuprizone-induced demyelination|journal= Journal of Neurochemistry |volume= 121|issue= 3|pages=418–427|year=2012 |doi= 10.1111/j.1471-4159.2011.07363.x|pmid= 21699540|pmc= 3220805}}</ref>
The presence of myelin debris has been correlated with damaging inflammation as well as poor regeneration, due to the presence of inhibitory myelin components.<ref name="Clarner, T. 2012 1468–1480">{{cite journal|author= Clarner, T. |last2=Diederichs|first2=F.|last3=Berger|first3=K.|last4=Denecke|first4=B.|last5=Gan|first5=L.|last6=Van Der Valk|first6=P.|last7=Beyer|first7=C.|last8=Amor|first8=S.|last9=Kipp|first9=M. |title= Myelin debris regulates inflammatory responses in an experimental demyelination animal model and multiple sclerosis lesions|journal= Glia |volume= 60|issue= 10|pages=1468–1480|year=2012 |doi= 10.1002/glia.22367|pmid= 22689449 }}</ref><ref name="pmid24961530">{{cite journal| author=Podbielska M, Banik NL, Kurowska E, Hogan EL| title=Myelin recovery in multiple sclerosis: the challenge of remyelination.|journal=Brain Sci|year= 2013|volume= 3|issue= 4|pages= 1282–324|pmid=24961530|doi=10.3390/brainsci3031282|pmc=4061877}}</ref>


[[Immunotherapy|Immunomodulatory drugs]] such as [[fingolimod]] have been shown to reduce immune-mediated damage to the CNS, preventing further damage in patients with MS. The drug targets the role of [[macrophage]]s in disease progression.<ref name="pmid22888218">{{cite journal |vauthors=Gasperini C, Ruggieri S |title=Development of oral agent in the treatment of multiple sclerosis: how the first available oral therapy, fingolimod will change therapeutic paradigm approach |journal=Drug Des Devel Ther |volume=6 |issue= |pages=175–86 |date=2012 |pmid=22888218 |pmc=3414371 |doi=10.2147/DDDT.S8927 |doi-access=free }}</ref><ref name="pmid12401395">{{cite journal |vauthors=Ransohoff RM, Howe CL, Rodriguez M |title=Growth factor treatment of demyelinating disease: at last, a leap into the light |journal=Trends Immunol |volume=23 |issue=11 |pages=512–6 |date=November 2002 |pmid=12401395 |doi=10.1016/s1471-4906(02)02321-9}}</ref>
[[N-cadherin]] is expressed in regions of active remyelination and may play an important role in generating a local environment conducive to remyelination.<ref name="Hochmeister, S. 2012 70–77">{{cite journal|author= Hochmeister, S. |last2=Romauch|first2=M|last3=Bauer|first3=J|last4=Seifert-Held|first4=T|last5=Weissert|first5=R|last6=Linington|first6=C|last7=Hurtung|first7=H.P.|last8=Fazekas|first8=F|last9=Storch|first9=M.K. |title= Re-expression of n-cadherin in remyelinating lesions of experimental inflammatory demyelination|journal= Experimental Neurology |volume= 237|issue= 1|pages=70–77 |year=2012 |doi= 10.1016/j.expneurol.2012.06.010|pmid= 22735489 }}</ref> N-cadherin [[agonist]]s have been identified and observed to stimulate [[neurite]] growth and cell migration, key aspects of promoting axon growth and remyelination after injury or disease.<ref name="Burden-Gulley, S.M. 2010 842–849">{{cite journal|author= Burden-Gulley, S.M. |last2=Gates|first2=T.J.|last3=Craig|first3=S.E.L.|last4=Gupta|first4=M.|last5=Brady-Kalnay|first5=S.M. |title= Stimulation of n-cadherin-dependent neurite outgrowth by small molecule peptide mimetic agonists of the n-cadherin hav motif|journal= Peptides |volume= 31|issue= 5|pages=842–849|year=2010|doi= 10.1016/j.peptides.2010.02.002|pmid= 20153391}}</ref>


Manipulating [[thyroid hormone]] levels may become a viable strategy to promote remyelination and prevent irreversible damage in MS patients.<ref name="pmid22421533">{{cite journal |vauthors=Silvestroff L, Bartucci S, Pasquini J, Franco P |title=Cuprizone-induced demyelination in the rat cerebral cortex and thyroid hormone effects on cortical remyelination |journal=Exp Neurol |volume=235 |issue=1 |pages=357–67 |date=May 2012 |pmid=22421533 |doi=10.1016/j.expneurol.2012.02.018 |s2cid=1534460}}</ref>
[[Immunotherapy|Immunomodulatory drugs]] such as [[fingolimod]] have been shown to reduce immune-mediated damage to the CNS, preventing further damage in patients with MS. The drug targets the role of [[macrophage]]s in disease progression.<ref>{{cite journal|author= Gasperini, C.|last2=Ruggieri|first2=S. |title= Development of oral agent in the treatment of multiple sclerosis- how the first available oral therapy, fingolimod will change therapeutic paradigm approach|journal= Drug Design, Development and Therapy |volume= 6|pages=175–186|year=2012 |doi= 10.2147/DDDT.S8927|pmid=22888218|pmc= 3414371}}</ref><ref>{{cite journal|author= Ransohoff, R.M.|last2=Hower|first2=C.L.|last3=Rodriquez|first3=M. |title= Growth factor treatment of demyelinating disease- at last, a leap into the light|journal= Trends in Immunology |volume= 23|issue=11 |pages=512–516|year=2005 |doi= 10.1016/S1471-4906(02)02321-9|pmid= 12401395}}</ref>
It has also been shown that [[Insufflation|intranasal]] administration of [[Transferrin|apotransferrin]] (aTf) can protect myelin and induce remyelination.<ref name="pmid22736466">{{cite journal |vauthors=Guardia Clausi M, Paez PM, Campagnoni AT, Pasquini LA, Pasquini JM |title=Intranasal administration of aTf protects and repairs the neonatal white matter after a cerebral hypoxic-ischemic event |journal=Glia |volume=60 |issue=10 |pages=1540–54 |date=October 2012 |pmid=22736466 |doi=10.1002/glia.22374 |s2cid=28658807|hdl=11336/67318 |hdl-access=free }}</ref>

Finally, electrical stimulation which activates [[neural stem cells]] may provide a method by which regions of demyelination can be repaired.<ref name="pmid22588976">{{cite journal |vauthors=Sherafat MA, Heibatollahi M, Mongabadi S, Moradi F, Javan M, Ahmadiani A |title=Electromagnetic field stimulation potentiates endogenous myelin repair by recruiting subventricular neural stem cells in an experimental model of white matter demyelination |journal=J Mol Neurosci |volume=48 |issue=1 |pages=144–53 |date=September 2012 |pmid=22588976 |doi=10.1007/s12031-012-9791-8 |s2cid=15779187}}</ref>
Manipulating [[thyroid hormone]] levels may become a viable strategy to promote remyelination and prevent irreversible damage in MS patients.<ref name="Silverstroff, L. 2012 357–367">{{cite journal|author= Silverstroff, L.|last2=Batucci|first2=S.|last3=Pasquini|first3=J.|last4=Franco|first4=P. |title= Cuprizone-induced demyelination in the rat cerebral cortex and thyroid hormone effects on cortical remyelination|journal= Experimental Neurology |volume= 235|issue= 1|pages=357–367|year=2012 |doi= 10.1016/j.expneurol.2012.02.018|pmid= 22421533}}</ref>
It has also been shown that [[Insufflation|intranasal]] administration of [[Transferrin|apotransferrin]] (aTf) can protect myelin and induce remyelination.<ref name="Clausi, M.G. 2012 1540–1554">{{cite journal|author= Clausi, M.G.|last2=Paez|first2=P.M.|last3=Campagnoni|first3=A.T.|last4=Pasquini|first4=L.A.|last5=Pasquini|first5=J.M.|last6=Ahmadiani|first6=A. |title= Intranasal administration of atf protects and repairs the neonatal white matter after a cerebral hypoxic-ischemic event|journal=Glia|volume= 60|issue= 10|pages=1540–1554|year=2012 |doi= 10.1002/glia.22374|pmid= 22736466}}</ref>
Finally, electrical stimulation which activates [[neural stem cells]] may provide a method by which regions of demyelination can be repaired.<ref>{{cite journal|author= Sherafat, M.A.|last2=Heibatollahi|first2=M.|last3=Mongabadi|first3=S.|last4=Moradi|first4=F.|last5=Javan|first5=M.|last6=Ahmadiani|first6=A. |title= Electromagnetic field stimulation potentiates endogenous myelin repair by recruiting subventricular neural stem cells in an experimental model of white matter demyelination|journal= Journal of Molecular Neuroscience |volume= 48|issue= 1|pages=144–153|year=2012 |doi= 10.1007/s12031-012-9791-8|pmid= 22588976}}</ref>


== In other animals ==
== In other animals ==
Demyelinating diseases/disorders have been found worldwide in various animals. Some of these animals include mice, pigs, cattle, hamsters, rats, sheep, Siamese kittens, and a number of dog breeds (including Chow Chow, Springer Spaniel, Dalmatian, Samoyed, Golden Retriever, Lurcher, Bernese Mountain Dog, Vizsla, Weimaraner, Australian Silky Terrier, and mixed breeds).<ref>{{cite news | url = http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/100500.htm | title = The Merck Veterinary Manual – Demyelinating Disorders: Introduction | author1 = Merck Sharp | author2 = Dohme Corp | year = 2011 | accessdate = 2012-10-30 | work = Merck Veterinary Manual | url-status = live | archive-url = https://web.archive.org/web/20101219083714/http://merckvetmanual.com/mvm/index.jsp?cfile=htm%2Fbc%2F100500.htm | archive-date = 2010-12-19 }}</ref><ref>{{cite news | url = https://www.ncbi.nlm.nih.gov/books/NBK83700/ | title = Johnson RT. DEMYELINATING DISEASES. In: Institute of Medicine (US) Forum on Microbial Threats; Knobler SL, O'Connor S, Lemon SM, et al., editors. The Infectious Etiology of Chronic Diseases: Defining the Relationship, Enhancing the Research, and Mitigating the Effects: Workshop Summary. Washington (DC): National Academies Press (US) | year = 2004 | accessdate = 2012-10-30 | work = NCBI}}</ref>
Demyelinating diseases/disorders have been found worldwide in various animals. Some of these animals include mice, pigs, cattle, hamsters, rats, sheep, Siamese kittens, and a number of dog breeds (including Chow Chow, Springer Spaniel, Dalmatian, Samoyed, Golden Retriever, Lurcher, Bernese Mountain Dog, Vizsla, Weimaraner, Australian Silky Terrier, and mixed breeds).<ref>{{cite web |url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/100500.htm |title=Merck Veterinary Manual – Demyelinating Disorders: Introduction |author=<!--Not stated--> |date= |website= |publisher= |access-date=2012-10-30 |archive-url=https://web.archive.org/web/20101219083714if_/http://merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/100500.htm |archive-date=2010-12-19}}</ref><ref>{{cite book |vauthors=Johnson RT |title=The Infectious Etiology of Chronic Diseases: Defining the Relationship, Enhancing the Research, and Mitigating the Effects: Workshop Summary. |chapter=Demyelinating Diseases |year=2004 |url=https://www.ncbi.nlm.nih.gov/books/NBK83700/ |publisher=NIH}}</ref>

Another notable animal found able to contract a demyelinating disease is the [[northern fur seal]]. Ziggy Star, a female northern fur seal, was treated at [[the Marine Mammal Center]] beginning in March 2014 <ref>{{cite web |url=http://wtnh.com/2014/12/22/ziggy-star-at-mystic-aquarium/ |title=Archived copy |accessdate=2016-10-25 |url-status=live |archive-url=https://web.archive.org/web/20161025112401/http://wtnh.com/2014/12/22/ziggy-star-at-mystic-aquarium/ |archive-date=2016-10-25 }}</ref> and was noted as the first reported case of such disease in a marine mammal. She was later transported to [[Mystic Aquarium & Institute for Exploration]] for lifelong care as an ambassador to the public.<ref>{{cite web|title=Ziggy Star has a Neurologic Condition|url=http://www.marinemammalcenter.org/about-us/News-Room/2013-news-archives/ziggy-star-has-a-neurologic-condition.html#.Uu6Q6z1dXtU|publisher=The Marine Mammal Center|accessdate=2 February 2014|url-status=live|archive-url=https://web.archive.org/web/20140219181041/http://www.marinemammalcenter.org/about-us/News-Room/2013-news-archives/ziggy-star-has-a-neurologic-condition.html#.Uu6Q6z1dXtU|archive-date=19 February 2014}}</ref>


== See also ==
== See also ==
* [[Degenerative disease]]

*[[Multiple sclerosis borderline]]
* [[Multiple sclerosis borderline]]
*[[The Lesion Project]] (multiple sclerosis)
* [[The Lesion Project]] (multiple sclerosis)
*[[The Myelin Project]]
* [[The Myelin Project]]
*[[Myelin Repair Foundation]]
* [[Myelin Repair Foundation]]


== References ==
== References ==
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{{Medical resources
| DiseasesDB =17472
| DiseasesDB =17472
| ICD10 = {{ICD10|G|35||g|35}}-{{ICD10|G|37||g|35}}, {{ICD10|G|61|0|g|60}}
| ICD10 = {{ICD10|G|35||g|35}}-{{ICD10|G|37||g|35}}, {{ICD10|G|61|0|g|60}}
| ICD9 = {{ICD9|340}}-{{ICD9|341}}, {{ICD9|357.0}}
| ICD9 = {{ICD9|340}}-{{ICD9|341}}, {{ICD9|357.0}}
| ICDO =
| ICDO =
| OMIM =
| OMIM =
| MedlinePlus =
| MedlinePlus =
| eMedicineSubj =
| eMedicineSubj =
| eMedicineTopic =
| eMedicineTopic =
| MeshID = D003711
| MeshID = D003711
}}
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{{CNS diseases of the nervous system}}
{{CNS diseases of the nervous system}}

Latest revision as of 21:14, 9 March 2024

Demyelinating disease
Photomicrograph of a demyelinating MS-lesion: Immunohistochemical staining for CD68 highlights numerous macrophages (brown). Original magnification 10×.
SpecialtyNeurology Edit this on Wikidata

A demyelinating disease refers to any disease affecting the nervous system where the myelin sheath surrounding neurons is damaged.[1] This damage disrupts the transmission of signals through the affected nerves, resulting in a decrease in their conduction ability. Consequently, this reduction in conduction can lead to deficiencies in sensation, movement, cognition, or other functions depending on the nerves affected.

Various factors can contribute to the development of demyelinating diseases, including genetic predisposition, infectious agents, autoimmune reactions, and other unknown factors. Proposed causes of demyelination include genetic predisposition, environmental factors such as viral infections or exposure to certain chemicals. Additionally, exposure to commercial insecticides like sheep dip, weed killers, and flea treatment preparations for pets, which contain organophosphates, can also lead to nerve demyelination.[2] Chronic exposure to neuroleptic medications may also cause demyelination.[3] Furthermore, deficiencies in vitamin B12 can result in dysmyelination.[4][5]

Demyelinating diseases are traditionally classified into two types: demyelinating myelinoclastic diseases and demyelinating leukodystrophic diseases. In the first group, a healthy and normal myelin is destroyed by toxic substances, chemicals, or autoimmune reactions. In the second group, the myelin is inherently abnormal and undergoes degeneration.[6] The Poser criteria named this second group dysmyelinating diseases.[7]

In the most well-known demyelinating disease, multiple sclerosis, evidence suggests that the body's immune system plays a significant role. Acquired immune system cells, specifically T-cells, are found at the site of lesions. Other immune system cells, such as macrophages (and possibly mast cells), also contribute to the damage.[8]

Signs and symptoms[edit]

Symptoms and signs that present in demyelinating diseases are different for each condition. These symptoms and signs can present in a person with a demyelinating disease:[9]

Evolutionary considerations[edit]

The role of prolonged cortical myelination in human evolution has been implicated as a contributing factor in some cases of demyelinating disease. Unlike other primates, humans exhibit a unique pattern of postpubertal myelination, which may contribute to the development of psychiatric disorders and neurodegenerative diseases that present in early adulthood and beyond. The extended period of cortical myelination in humans may allow greater opportunities for disruption in myelination, resulting in the onset of demyelinating disease.[10] Furthermore, humans have significantly greater prefrontal white matter volume than other primate species, which implies greater myelin density.[11] Increased myelin density in humans as a result of a prolonged myelination may, therefore, structure risk for myelin degeneration and dysfunction. Evolutionary considerations for the role of prolonged cortical myelination as a risk factor for demyelinating disease are particularly pertinent given that genetics and autoimmune deficiency hypotheses fail to explain many cases of demyelinating disease. As has been argued, diseases such as multiple sclerosis cannot be accounted for by autoimmune deficiency alone, but strongly imply the influence of flawed developmental processes in disease pathogenesis.[12] Therefore, the role of the human-specific prolonged period of cortical myelination is an important evolutionary consideration in the pathogenesis of demyelinating disease.[citation needed]

Diagnosis[edit]

Various methods/techniques are used to diagnose demyelinating diseases:

Types[edit]

Demyelinating diseases can be divided in those affecting the central nervous system (CNS) and those affecting the peripheral nervous system (PNS). They can also be classified by the presence or absence of inflammation. Finally, a division may be made based on the underlying cause of demyelination: the disease process can be demyelinating myelinoclastic, wherein myelin is destroyed; or dysmyelinating leukodystrophic, wherein myelin is abnormal and degenerative.

CNS[edit]

The demyelinating disorders of the central nervous system include:[citation needed]

The myelinoclastic disorders are typically associated with symptoms such as optic neuritis and transverse myelitis, because the demyelinating inflammation can affect the optic nerve or spinal cord. Many are idiopathic. Both myelinoclastic and leukodystrophic modes of disease may result in lesional demyelinations of the central nervous system.

PNS[edit]

Guillain–Barré syndrome – demyelination

The demyelinating diseases of the peripheral nervous system include:[citation needed]

Treatment[edit]

Treatments are patient-specific and depend on the symptoms that present with the disorder, as well as the progression of the condition. Improvements to the patient's life may be accomplished through the management of symptoms or slowing of the rate of demyelination. Treatment can include medication, lifestyle changes (i.e. smoking cessation, increased rest, and dietary changes), counselling, relaxation, physical exercise, patient education, and in some cases, deep brain thalamic stimulation (to ameliorate tremors).[13]: 227–248 

Prognosis[edit]

Prognosis depends on the condition itself. Some conditions such as MS depend on the subtype of the disease and various attributes of the patient such as age, sex, initial symptoms, and the degree of disability the patient experiences.[14] Life expectancy in MS patients is 5 to 10 years lower than unaffected people.[15] MS is an inflammatory demyelinating disease of the central nervous system (CNS) that develops in genetically susceptible individuals after exposure to unknown environmental trigger(s). The bases for MS are unknown but are strongly suspected to involve immune reactions against autoantigens, particularly myelin proteins. The most accepted hypothesis is that dialogue between T-cell receptors and myelin antigens leads to an immune attack on the myelin-oligodendrocyte complex. These interactions between active T cells and myelin antigens provoke a massive destructive inflammatory response and promote continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators.[16] Other conditions such as central pontine myelinolysis have about a third of patients recover and the other two-thirds experience varying degrees of disability.[17] In some cases, such as transverse myelitis, the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition.[citation needed]

Epidemiology[edit]

Incidence of demyelinating diseases varies by disorder. Some conditions, such as tabes dorsalis appear predominantly in males and begin in midlife. Optic neuritis, though, occurs preferentially in females typically between the ages of 30 and 35.[18] Other conditions such as multiple sclerosis vary in prevalence depending on the country and population.[19] This condition can appear in children and adults.[15]

Research[edit]

Much of the research conducted on demyelinating diseases is targeted towards discovering the mechanisms by which these disorders function in an attempt to develop therapies and treatments for individuals affected by these conditions. For example, proteomics has revealed several proteins which contribute to the pathophysiology of demyelinating diseases.[20] For example, COX-2 has been implicated in oligodendrocyte death in animal models of demyelination.[21] The presence of myelin debris has been correlated with damaging inflammation as well as poor regeneration, due to the presence of inhibitory myelin components.[22][23]

N-cadherin is expressed in regions of active remyelination and may play an important role in generating a local environment conducive to remyelination.[24] N-cadherin agonists have been identified and observed to stimulate neurite growth and cell migration, key aspects of promoting axon growth and remyelination after injury or disease.[25]

Immunomodulatory drugs such as fingolimod have been shown to reduce immune-mediated damage to the CNS, preventing further damage in patients with MS. The drug targets the role of macrophages in disease progression.[26][27]

Manipulating thyroid hormone levels may become a viable strategy to promote remyelination and prevent irreversible damage in MS patients.[28] It has also been shown that intranasal administration of apotransferrin (aTf) can protect myelin and induce remyelination.[29] Finally, electrical stimulation which activates neural stem cells may provide a method by which regions of demyelination can be repaired.[30]

In other animals[edit]

Demyelinating diseases/disorders have been found worldwide in various animals. Some of these animals include mice, pigs, cattle, hamsters, rats, sheep, Siamese kittens, and a number of dog breeds (including Chow Chow, Springer Spaniel, Dalmatian, Samoyed, Golden Retriever, Lurcher, Bernese Mountain Dog, Vizsla, Weimaraner, Australian Silky Terrier, and mixed breeds).[31][32]

See also[edit]

References[edit]

  1. ^ "demyelinating disease" at Dorland's Medical Dictionary
  2. ^ Lotti M, Moretto A (2005). "Organophosphate-induced delayed polyneuropathy". Toxicol Rev. 24 (1): 37–49. doi:10.2165/00139709-200524010-00003. PMID 16042503. S2CID 29313644.
  3. ^ Konopaske GT, Dorph-Petersen KA, Sweet RA, Pierri JN, Zhang W, Sampson AR, Lewis DA (April 2008). "Effect of chronic antipsychotic exposure on astrocyte and oligodendrocyte numbers in macaque monkeys". Biol Psychiatry. 63 (8): 759–65. doi:10.1016/j.biopsych.2007.08.018. PMC 2386415. PMID 17945195.
  4. ^ Agadi S, Quach MM, Haneef Z (2013). "Vitamin-responsive epileptic encephalopathies in children". Epilepsy Res Treat. 2013: 510529. doi:10.1155/2013/510529. PMC 3745849. PMID 23984056.
  5. ^ Yoganathan S, Varman M, Oommen SP, Thomas M (2017). "A Tale of Treatable Infantile Neuroregression and Diagnostic Dilemma with Glutaric Aciduria Type I". J Pediatr Neurosci. 12 (4): 356–359. doi:10.4103/jpn.JPN_35_17. PMC 5890558. PMID 29675077.
  6. ^ Fernández O, Fernández VE, Guerrero M (2015). "Demyelinating diseases of the central nervous system". Medicine. 11 (77): 4601–4609. doi:10.1016/j.med.2015.04.001.
  7. ^ POSER CM (March 1961). "Leukodystrophy and the concept of dysmyelination". Arch Neurol. 4 (3): 323–32. doi:10.1001/archneur.1961.00450090089013. PMID 13737358.
  8. ^ Laetoli (January 2008). "Demyelination". Archived from the original on 2012-07-28.
  9. ^ "Symptoms of Demyelinating Disorders - Right Diagnosis." Right Diagnosis. Right Diagnosis, 01 Feb 2012. Web. 24 Sep 2012
  10. ^ Miller DJ, Duka T, Stimpson CD, Schapiro SJ, Baze WB, McArthur MJ, Fobbs AJ, Sousa AM, Sestan N, Wildman DE, Lipovich L, Kuzawa CW, Hof PR, Sherwood CC (October 2012). "Prolonged myelination in human neocortical evolution". Proc Natl Acad Sci U S A. 109 (41): 16480–5. Bibcode:2012PNAS..10916480M. doi:10.1073/pnas.1117943109. PMC 3478650. PMID 23012402.
  11. ^ Schoenemann PT, Sheehan MJ, Glotzer LD (February 2005). "Prefrontal white matter volume is disproportionately larger in humans than in other primates". Nat Neurosci. 8 (2): 242–52. doi:10.1038/nn1394. PMID 15665874. S2CID 205430527.
  12. ^ Chaudhuri A (October 2013). "Multiple sclerosis is primarily a neurodegenerative disease". J Neural Transm (Vienna). 120 (10): 1463–6. doi:10.1007/s00702-013-1080-3. PMID 23982272. S2CID 8575687.
  13. ^ a b c d e f g Freedman MS (2005). Advances in Neurology Volume 98: Multiple Sclerosis and Demyelinating Diseases. Philadelphia: Lippincott Williams & Wilkins. p. 112. ISBN 0781751705.
  14. ^ Weinshenker BG (1994). "Natural history of multiple sclerosis". Ann Neurol. 36 Suppl: S6–11. doi:10.1002/ana.410360704. PMID 8017890. S2CID 7140070.
  15. ^ a b Compston A, Coles A (October 2008). "Multiple sclerosis". Lancet. 372 (9648): 1502–17. doi:10.1016/S0140-6736(08)61620-7. PMID 18970977. S2CID 195686659.
  16. ^ Minagar A, Alexander JS (December 2003). "Blood-brain barrier disruption in multiple sclerosis". Mult Scler. 9 (6): 540–9. doi:10.1191/1352458503ms965oa. PMID 14664465. S2CID 10189144.
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