Demyelinating disease: Difference between revisions
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{{short description|Any neurological disease in which the myelin sheath of neurons is damaged}} |
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{{Infobox medical condition |
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| name = Demyelinating disease |
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| image = MS Demyelinisation CD68 10xv2.jpg |
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| caption = Photomicrograph of a demyelinating MS-lesion: [[Immunohistochemistry|Immunohistochemical staining]] for CD68 highlights numerous macrophages (brown). Original magnification 10×. |
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ICD10 = {{ICD10|G|35||g|35}}-{{ICD10|G|37||g|35}}, {{ICD10|G|61|0|g|60}} | |
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ICD9 = {{ICD9|340}}-{{ICD9|341}}, {{ICD9|357.0}} | |
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A '''demyelinating disease''' |
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. |
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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> |
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Demyelinating diseases are traditionally classified |
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> |
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In the most known |
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> |
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[[Vitamin B12]] deficiency can cause demyelination. |
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== Evolutionary considerations == |
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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 }}</ref> Furthermore, it has been noted that humans have significantly greater prefrontal white matter volume than other primate species, which implies greater myelin density.<ref>{{cite journal | author = Schoenemann, Thomas P., Sheehan Michael J., Glotzer L. Daniel | year = 2005 | title = Prefrontal White Matter Volume Is Disproportionately Larger in Humans than in Other Primates | url = | journal = Nature Neuroscience | volume = 8 | issue = 2| pages = 242–52 | doi=10.1038/nn1394| pmid = 15665874 | last2 = Sheehan | last3 = Glotzer }}</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 | url = | journal = J Neural Transm | volume = 120 | issue = | pages = 1463–466 | doi=10.1007/s00702-013-1080-3}}</ref> Therefore, the role of the human-specific prolonged period of cortical myelination is an important evolutionary consideration in the pathogenesis of demyelinating disease. |
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== Signs and symptoms == |
== Signs and symptoms == |
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Symptoms that present in demyelinating diseases are different for each condition. |
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> |
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{{div col}} |
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<div align="center"> |
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* Blurred double vision ([[Diplopia]]) |
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{| align="left" summary="first column is left column" |
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|- |
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| align="left" | |
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* Blurred double vision |
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* [[Ataxia]] |
* [[Ataxia]] |
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* [[Clonus]] |
* [[Clonus]] |
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* Incoordination |
* Incoordination |
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* [[Paresthesias]] |
* [[Paresthesias]] |
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* Ocular paralysis (cranial nerve palsy) |
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|} |
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{| summary="middle column visually second" |
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|- |
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| align="left" | |
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* Ocular paralysis |
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* Impaired muscle coordination |
* Impaired muscle coordination |
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* Weakness (muscle) |
* Weakness (muscle) |
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* Loss of sensation |
* Loss of sensation |
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* Impaired vision |
* Impaired vision |
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* Neurological symptoms |
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* Unsteady gait |
* Unsteady gait |
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* Spastic [[paraparesis]] |
* Spastic [[paraparesis]] |
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* Hearing problems |
* Hearing problems |
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* Speech problems |
* Speech problems |
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{{div col end}} |
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|}</div> |
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== Evolutionary considerations == |
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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}} |
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== Diagnosis == |
== Diagnosis == |
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Various methods/techniques are used to diagnose demyelinating diseases: |
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* Exclusion of other conditions that have overlapping symptoms<ref name="Freedman">{{cite book| |
* 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> |
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* [[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 |
* [[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}} |
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* [[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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* [[cerebrospinal fluid|Cerebrospinal fluid analysis]] (CSF) can be extremely beneficial in the diagnosis of central nervous system infections. A CSF [[culture]] examination may yield the [[microorganism]] that caused the infection.<ref name="Freedman" /> |
* [[cerebrospinal fluid|Cerebrospinal fluid analysis]] (CSF) can be extremely beneficial in the diagnosis of central nervous system infections. A CSF [[culture]] examination may yield the [[microorganism]] that caused the infection.<ref name="Freedman" /> |
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* [[Magnetic resonance spectroscopy|Quantitative proton magnetic resonance spectroscopy]] (MRS) is a |
* [[Magnetic resonance spectroscopy|Quantitative proton magnetic resonance spectroscopy]] (MRS) is a noninvasive analytical technique that has been used to study metabolic changes in brain tumors, strokes, seizure disorders, Alzheimer's disease, depression, and other diseases affecting the brain. It has also been used to study the metabolism of other organs such as muscles.<ref name="Freedman"/>{{rp|309}} |
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* [[Medical diagnosis|Diagnostic criteria]] refers to a specific combination of signs, symptoms, and test results that the [[clinician]] uses in an attempt to determine the correct diagnosis.<ref name="Freedman"/>{{rp|320}} |
* [[Medical diagnosis|Diagnostic criteria]] refers to a specific combination of signs, symptoms, and test results that the [[clinician]] uses in an attempt to determine the correct diagnosis.<ref name="Freedman"/>{{rp|320}} |
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* [[Fluid-attenuated inversion recovery]] (FLAIR) uses a [[pulse sequence]] to suppress cerebrospinal fluid and show lesions more clearly, and is used for example in multiple sclerosis evaluation. |
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== |
=== Types === |
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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. |
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Treatment typically involves improving the patient's quality of life. This is accomplished through the management of symptoms or slowing the rate of demyelination. Treatment can include medication, lifestyle changes (i.e. quit smoking, adjusting daily schedules to include rest periods and dietary changes), counselling, relaxation, physical exercise, patient education and, in some cases, deep brain [[Thalamus|thalamic]] stimulation (in the case of [[tremors]]).<ref name="Freedman"/>{{rp|227–248}} The progressive phase of MS appears driven by the innate immune system, which will directly contribute to the neurodegenerative changes that occur in progressive MS. Until now, there are no therapies that specifically target innate immune cells in MS. As the role of innate immunity in MS becomes better defined, it may be possible to better treat MS by targeting the innate immune system.<ref>{{cite journal|last=Mayo|first=Lior|title=The Innate Immune System in Demyelinating Disease|journal=Immunological Reviews|date=21 June 2012|doi=10.1111/j.1600-065X.2012.01135.x|last2=Quintana|first2=Francisco J.|last3=Weiner|first3=Howard L.|volume=248|pages=170–87|pmid=22725961|issue=1|pmc=3383669}}</ref> |
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====CNS==== |
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Treatments are patient-specific and depend on the symptoms that present with the disorder, as well as the progression of the condition. |
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The demyelinating disorders of the [[central nervous system]] include:{{citation needed|date=August 2021}} |
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* Myelinoclastic or demyelinating disorders: |
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** Typical forms of [[multiple sclerosis]] |
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** [[Neuromyelitis optica]], or Devic's disease |
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** [[Idiopathic inflammatory demyelinating diseases]] |
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* Leukodystrophic or dysmyelinating disorders: |
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** CNS [[Neuropathy (disambiguation)|neuropathies]] such as those produced by [[vitamin B12 deficiency|vitamin B<sub>12</sub> deficiency]] |
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** [[Central pontine myelinolysis]] |
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** [[Myelopathy|Myelopathies]] such as [[tabes dorsalis]] (syphilitic myelopathy) |
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** [[leukoencephalopathy|Leukoencephalopathies]] such as [[progressive multifocal leukoencephalopathy]] |
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** [[Leukodystrophy|Leukodystrophies]] |
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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]]. |
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== Prognosis == |
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Prognosis depends on the condition itself. Some conditions such as multiple sclerosis 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 Multiple sclerosis 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 |url= |pmid=18970977}}</ref> MS is an inflammatory demyelinating disease of the |
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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 promotes continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators.<ref>{{cite web|last=Minegar|first=Alireza|title=Blood-Brain Barrier Disruption in Multiple Sclerosis|url=http://msj.sagepub.com/content/9/6/540|publisher=Sage Journals|accessdate=October 28, 2012}}</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 |url= |pmid=16210283}}</ref> There are cases, such as [[transverse myelitis]] where the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition. |
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== |
====PNS==== |
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[[File:Guillain-barré syndrome - Nerve Damage.gif|thumb|Guillain–Barré syndrome – demyelination]] |
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Incidence of demyelinating diseases vary from disorder to disorder. Some conditions, such as [[Tabes dorsalis]] appear predominantly in males and begins in mid-life. [[Optic neuritis]] on the other hand, 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 as well as adults.<ref name="Compston2008" /> |
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The demyelinating diseases of the [[peripheral nervous system]] include:{{citation needed|date=August 2021}} |
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* [[Guillain–Barré syndrome]] and its chronic counterpart, [[chronic inflammatory demyelinating polyneuropathy]] |
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* [[Anti-MAG peripheral neuropathy]] |
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* [[Charcot–Marie–Tooth disease]] and its counterpart [[Hereditary neuropathy with liability to pressure palsy]] |
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* [[Copper deficiency]]-associated conditions ([[peripheral neuropathy]], [[myelopathy]], and rarely [[optic neuropathy]]) |
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* [[Progressive inflammatory neuropathy]] |
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== |
== Treatment == |
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{{See also|Multiple sclerosis#Medications|Management of multiple sclerosis}} |
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Demyelinating diseases can be divided in those affecting the [[central nervous system]] and those presents in the [[peripheral nervous system]], presenting different [[Lesional demyelinations of the CNS|demyelination conditions]]. They can also be divided by other criteria in [[inflammation|inflammatory]] and non-inflammatory, according to the presence or lack of inflammation, and finally, a division can also be made depending on the underlying reason for demyelination in myelinoclastic (myelin is attacked by an external substance) and leukodystrophic (myelin degenerates without attacks) |
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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 [[Thalamus|thalamic]] stimulation (to ameliorate [[tremor]]s).<ref name="Freedman"/>{{rp|227–248}} |
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===Demyelinating disorders of the CNS=== |
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== Prognosis == |
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The demyelinating disorders of the central nervous system include: |
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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}} |
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== Epidemiology == |
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*Myelinoclastic disorders, in which myelin is attacked by external substances |
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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" /> |
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** standard [[Multiple sclerosis]], [[Devic's disease]] and other disorders with immune system involvement called [[idiopathic inflammatory demyelinating diseases|inflammatory demyelinating diseases]]. |
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*Leukodystrophic disorders, in which myelin is not properly produced: |
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** CNS [[Neuropathy (disambiguation)|Neuropathies]] like those produced by [[Vitamin B12 deficiency]] |
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** [[Central pontine myelinolysis]] |
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** [[Myelopathy|Myelopathies]] like [[Tabes dorsalis]] (syphilitic Myelopathy) |
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** [[leukoencephalopathy|leukoencephalopathies]] like [[Progressive multifocal leukoencephalopathy]] |
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** [[Leukodystrophy|Leukodystrophies]] |
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These disorders are normally associated also with the conditions [[Optic neuritis]] and [[Transverse myelitis]], which are inflammatory conditions, because inflammation and demyelination are frequently associated. Some of them are [[idiopathic]] and for some others the cause has been found, like some cases of [[neuromyelitis optica]]. |
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===Demyelinating diseases of the peripheral nervous system=== |
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The demyelinating diseases of the [[peripheral nervous system]] include: |
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** [[Guillain–Barré syndrome]] and its chronic counterpart, [[chronic inflammatory demyelinating polyneuropathy]] |
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** [[Anti-MAG peripheral neuropathy]] |
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** [[Charcot–Marie–Tooth disease]] |
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** [[Copper deficiency]] associated conditions ([[peripheral neuropathy]], [[myelopathy]], and rarely [[optic neuropathy]]) |
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** [[Progressive inflammatory neuropathy]] |
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== Research == |
== Research == |
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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> |
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Research is being conducted in a variety of very specific areas. The focus of this research is aimed at gaining more insight into how demyelinating disorders affect the central nervous system and peripheral nervous system,<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><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>{{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= |pages=119–202|year=2005 |doi= 10.1016/j.jchromb.2004.10.073}}</ref><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><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> how they develop and how these disorders are affected by various external inputs<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><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><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><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|issue= |pages=175–186|year=2012 |doi= 10.2147/DDDT.S8927}}</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> |
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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> |
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. Much of the research is targeted towards learning about the mechanisms by which these disorders function in an attempt to develop therapies and treatments for individuals affected by these conditions. |
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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> |
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[[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> |
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===Insights=== |
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Currently it is believed that [[N-cadherin]] plays a role in the myelination process. Experimentation has shown that N-cadherin plays an important role in producing a remyelination-facilitating environment.<ref name="Hochmeister, S. 2012 70–77"/> It has been shown in animal models that there is a direct correlation between the amount of myelin debris present and the degree of [[Inflammation]] observed.<ref name="Clarner, T. 2012 1468–1480"/> |
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[[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> |
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===Effects of environmental inputs=== |
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Experimentation has shown that manipulating the levels of [[thyroid hormone]] can be considered as a strategy to promote remyelination and prevent irreversible damage in Multiple sclerosis patients.<ref name="Silverstroff, L. 2012 357–367"/> 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"/> It has been shown that [[Insufflation|intranasal]] administration of aTf ([[Transferrin|apotransferrin]]) can protect myelin and induce remyelination.<ref name="Clausi, M.G. 2012 1540–1554"/> |
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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> |
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Much of the research referenced in this section has been conducted in 2012 and represents very new information about demyelinating diseases and potential therapies for them. |
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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> |
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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> |
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== In other animals == |
== In other animals == |
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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 |
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> |
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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>http://wtnh.com/2014/12/22/ziggy-star-at-mystic-aquarium/</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}}</ref> |
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== See also == |
== See also == |
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* [[Degenerative disease]] |
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*[[Multiple sclerosis borderline]] |
* [[Multiple sclerosis borderline]] |
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*[[The Lesion Project]] (multiple sclerosis) |
* [[The Lesion Project]] (multiple sclerosis) |
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*[[The Myelin Project]] |
* [[The Myelin Project]] |
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*[[Myelin Repair Foundation]] |
* [[Myelin Repair Foundation]] |
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== References == |
== References == |
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{{Reflist}} |
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{{Research help|Med}} |
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{{Reflist|30em}} |
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== External links == |
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{{Medical resources |
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| DiseasesDB =17472 |
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| ICD10 = {{ICD10|G|35||g|35}}-{{ICD10|G|37||g|35}}, {{ICD10|G|61|0|g|60}} |
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| ICD9 = {{ICD9|340}}-{{ICD9|341}}, {{ICD9|357.0}} |
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| ICDO = |
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| OMIM = |
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| MedlinePlus = |
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| eMedicineSubj = |
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| eMedicineTopic = |
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| MeshID = D003711 |
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{{CNS diseases of the nervous system}} |
{{CNS diseases of the nervous system}} |
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{{Demyelinating diseases of CNS}} |
{{Demyelinating diseases of CNS}} |
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[[Category:Neurological disorders]] |
[[Category:Neurological disorders]] |
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[[Category:Myelin disorders]] |
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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×. | |
| Specialty | Neurology  |
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]
- Blurred double vision (Diplopia)
- Ataxia
- Clonus
- Dysarthria
- Fatigue
- Clumsiness
- Hand paralysis
- Hemiparesis
- Genital anaesthesia
- Incoordination
- Paresthesias
- Ocular paralysis (cranial nerve palsy)
- Impaired muscle coordination
- Weakness (muscle)
- Loss of sensation
- Impaired vision
- Unsteady gait
- Spastic paraparesis
- Incontinence
- Hearing problems
- Speech problems
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:
- Exclusion of other conditions that have overlapping symptoms[13]
- 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.[13]: 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.[13]: 117
- Cerebrospinal fluid analysis (CSF) can be extremely beneficial in the diagnosis of central nervous system infections. A CSF culture examination may yield the microorganism that caused the infection.[13]
- Quantitative proton magnetic resonance spectroscopy (MRS) is a noninvasive analytical technique that has been used to study metabolic changes in brain tumors, strokes, seizure disorders, Alzheimer's disease, depression, and other diseases affecting the brain. It has also been used to study the metabolism of other organs such as muscles.[13]: 309
- Diagnostic criteria refers to a specific combination of signs, symptoms, and test results that the clinician uses in an attempt to determine the correct diagnosis.[13]: 320
- Fluid-attenuated inversion recovery (FLAIR) uses a pulse sequence to suppress cerebrospinal fluid and show lesions more clearly, and is used for example in multiple sclerosis evaluation.
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]
- Myelinoclastic or demyelinating disorders:
- Typical forms of multiple sclerosis
- Neuromyelitis optica, or Devic's disease
- Idiopathic inflammatory demyelinating diseases
- Leukodystrophic or dysmyelinating disorders:
- CNS neuropathies such as those produced by vitamin B12 deficiency
- Central pontine myelinolysis
- Myelopathies such as tabes dorsalis (syphilitic myelopathy)
- Leukoencephalopathies such as progressive multifocal leukoencephalopathy
- Leukodystrophies
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]
The demyelinating diseases of the peripheral nervous system include:[citation needed]
- Guillain–Barré syndrome and its chronic counterpart, chronic inflammatory demyelinating polyneuropathy
- Anti-MAG peripheral neuropathy
- Charcot–Marie–Tooth disease and its counterpart Hereditary neuropathy with liability to pressure palsy
- Copper deficiency-associated conditions (peripheral neuropathy, myelopathy, and rarely optic neuropathy)
- Progressive inflammatory neuropathy
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]- Degenerative disease
- Multiple sclerosis borderline
- The Lesion Project (multiple sclerosis)
- The Myelin Project
- Myelin Repair Foundation
References
[edit]- ^ "demyelinating disease" at Dorland's Medical Dictionary
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ POSER CM (March 1961). "Leukodystrophy and the concept of dysmyelination". Arch Neurol. 4 (3): 323–32. doi:10.1001/archneur.1961.00450090089013. PMID 13737358.
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