Patološki nistagmus: razlika između inačica
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{{prijevod-eng}}
'''Patološki nistagmus''' je oblik nehotične kretnje oka. Odlikuje se izmjeničnim glatkim kretanjem u jednom smjeru i sakadičkim kretanjem u drugom smjeru.
[[Image:Optokinetic nystagmus.gif|thumb||Horizontal [[optokinetic nystagmus]], a normal ([[physiological]]) form of nystagmus.]]
Kada se nistagmus javlja bez ispunjavanja svojih normalnih funkcija, to je patološki (odstupa od zdravog i normalnog stanja). Patološki nistagmus je rezultat oštećenja jedne ili više komponenti vestibularnog sustava, uključujući i polukružne kanale, otolitne organe i vestibulocerebellum-a.
Patološki nistagmus općenito uzrokuje maji stupanj vidne oštrine, iako raspon takog umanjenja široko varira. Ponekad je obrnuto-mnogi slijepi ljudi imaju nistagmus što je jedan od razloga da neki nose tamne naočale.
===Prevalencija===
Nistagmus je relativno uobičajeno kliničko stanje,koju ima jedna osoba od svakih 5000-10000 pojedinaca. U jednom istraživanju u Oxfordshire,Engleska, utvrđeno je po jedno u 670 djece u dobi od dvije godine s dijagnozom nistagmusa.
===Varijacije===
*'''Periferni nistagmus''' occurs as a result of either normal or diseased functional states of the vestibular system and may combine a rotational component with vertical or horizontal eye movements and may be ''spontaneous'', ''positional'', or ''evoked''.
**'''Pozicijski nistagmus ''' se javlja kod osoba kojima je glava u određenom - specifičnom položaju. Primjer tog stanja je benigni paroksizmalni pozicijski vertigo (BPPV).
**'''Gaze Induced nystagmus''' occurs or is exacerbated as a result of changing one's gaze toward or away from a particular side which has an affected vestibular apparatus.
**'''Post rotacijski nistagmus''' javlja se nakon što se stvori neravnoteža između normalne i oboljele strane. Npr. stimulacija vestibularnog sustava brzim drmanjem ili rotacijom glave.
**'''Spontani nistagmus''' je nistagmus koji nastaje bez obzira na položaj glave pacijenta
*'''Centralni nistagmus''' javlja se ili kao rezultat normalnih ili kao abnormalnih procesa koji se ne odnose na vestibularni organ. Npr. lezije u srednjem mozgu ili malom mozgu mogu rezultirati nistagmusom.
===Uzroci===
Uzroci nastanka patološkog nistagmusa mogu biti nasljedai, idiopatski kao i neurološki poremećaji ili može biti uzrokovan privremenom dezorijentiranošću (kao npr. brdska željeznička vožnja), drogama (alkoholom ili ostalim stimulansima koji utječu na SŽS kao što su soli litija, fenitoin i ekstazy).
====Kongenitalni nistagmus====
Kongenitalni nistagmus se javlja češće nego stečeni nistagmus. Mogu ga pratitit i drugi poremećaji kao što su mikro-očne anomalije ili Downov sindrom. Sam po sebi je blag i nije progresivan. Takve osobe često nisu svjesne svojih spontanih pokreta oka, ali vid im može biti oslabljen ovisno o težini pokreta.
*Infantilni:
:*[[Idiopatski]]
:*[[Albinizam]]
:*[[Aniridija]]
:*[[Leberova kongenitalna amauroza]]
:*Bilateralna [[hipoplazija očnog živca]]
:*Bilateralna kongenitalna [[katarakta]]
:*[[Rod monochromatism]]
:*[[Bolesti očnog živca]] ili [[makularne]]bolesti
:*[[Perzistentna tunica vasculosa lentis]]
*Latentni nistagmus
*Nystagmus blockage syndrome
X-vezani nistagmus - [[FRMD7]].<ref name="pmid18431453">{{cite journal |author=Li N, Wang L, Cui L, ''et al'' |title=Five novel mutations of the FRMD7 gene in Chinese families with X-linked infantile nystagmus |journal=Mol. Vis. |volume=14 |issue= |pages=733–8 |year=2008 |pmid=18431453 |doi= |url=}}</ref>
====Acquired====
=====Bolesti=====
Neke od bolesti čiji je patološki znak nistagmus:
*[[Benigni paroksizmalni pozicijski vertigo]] <ref name="pmid16878247">{{cite journal |author=Dorigueto RS, Ganança MM, Ganança FF |title=The number of procedures required to eliminate positioning nystagmus in benign paroxysmal positional vertigo |journal=Rev Bras Otorrinolaringol (Engl Ed) |volume=71 |issue=6 |pages=769–75 |year=2005 |pmid=16878247 |doi= |url=http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-72992005000600014&lng=en&nrm=iso&tlng=en}}</ref>
*[[Ozlijeda glave]]
*[[Moždani udar]] (najčešći uzrok u starijih ljudi)
*[[Ménièreova bolest ]] and other [[balance disorder]]s
*[[Multiple sclerosis]]
*[[Brain tumor]]s
*[[Wernicke-Korsakoff syndrome]]
*[[Encephalopathy]]
*[[Lateral medullary syndrome]]
*[[Aniridia]]
*[[Optic nerve hypoplasia]]
*[[Albinism]]
*[[Noonan syndrome]]
*[[Pelizaeus-Merzbacher disease]]
*[[Superior canal dehiscence syndrome]]
*[[Tullio phenomenon]]
*[[Horner's Syndrome]]
=====Toxic/metabolic=====
Nystagmus from toxic or metabolic reasons could be the result of the following:
*Alcohol intoxication (see above)
*[[Lithium pharmacology|Lithium]]
*[[Barbiturates]]
*[[Phenytoin]] (Dilantin)
*[[Salicylates]]
*[[Benzodiazepines]]
*[[Lysergic acid diethylamide]] (LSD)
*[[Phencyclidine]] (PCP)
*[[Ketamine]]
*Other anticonvulsants or sedatives
*[[Methylenedioxymethamphetamine]]
*[[Wernicke's encephalopathy]]
*[[Thiamine]] deficiency
=====Central nervous system disorders=====
If the pathologic nystagmus is based in the [[central nervous system]] (CNS), such as with a [[cerebellum|cerebellar]] problem, the nystagmus can be in any direction ''including'' horizontal. Purely vertical nystagmus is usually central in origin.
Causes include e.g.:
*[[Thalamus|Thalamic]] hemorrhage
*[[Tumor]]
*[[Stroke]]
*Trauma
*[[Multiple sclerosis]]
*[[Cerebellar ataxia]]
=====Other causes=====
*Vestibular Pathology ([[Ménière's disease]], SCDS ([[superior canal dehiscence syndrome]]), [[BPPV]], [[Labyrinthitis]])
*[[Trochlear nerve]] malfunction<ref name=Lindgren>{{cite book|
title=Kliniska färdigheter: Informationsutbytet mellan patient och läkare
|last=Lindgren|first=Stefan|isbn=91-44-37271-X|language=Swedish
|location=Lund|publisher=Studentlitteratur|year=1993}} </ref>
*Non-physiologic
===Diagnosis===
Nystagmus is very noticeable but little recognised. Nystagmus can be clinically investigated by using a number of [[non-invasive (medical)|non-invasive]] standard tests. The simplest one is [[Caloric reflex test]], in which one [[ear|external auditory meatus]] is irrigated with warm or cold water. The temperature gradient provokes the stimulation of the [[vestibulocochlear nerve]] and the consequent nystagmus.
The resulting movement of the eyes may be recorded and quantified by special devices called [[electronystagmograph]] (ENG), a form of [[electrooculography]] (an electrical method of measuring eye movements using external [[electrodes]]), or even less invasive devices called [[videoonystagmograph]] (VNG), a form of [[videooculography]](VOG) (a video-based method of measuring eye movements using external small cameras built into head masks). Special swinging chairs with electrical controls are also used in this test to induce rotatory nystagmus.
===Treatment===
Congenital nystagmus has traditionally been viewed as non-treatable, but medications have been discovered in recent years that show promise in some patients. In 1980, researchers discovered that a drug called [[baclofen]] could effectively stop periodic alternating nystagmus. Subsequently, [[gabapentin]], an anticonvulsant, was found to cause improvement in about half the patients who received it to relieve symptoms of nystagmus. Other drugs found to be effective against nystagmus in some patients include [[memantine]]<ref> Memantine/Gabapentin for the treatment of congenital nystagmus. [http://www.ncbi.nlm.nih.gov/pubmed/17764629 PMID: 17764629]</ref>, [[levetiracetam]], 3,4-diaminopyridine, [[4-Aminopyridine|4-aminopyridine]], and [[acetazolamide]].<ref name=Groves2006>Groves, Nancy.
Many options to treat nystagmus, more in development. ''Ophthalmology Times'', [[March 15]] [[2006]]. [http://www.ophthalmologytimes.com/ophthalmologytimes/article/articleDetail.jsp?id=313686&ref=25]</ref> Several therapeutic approaches, such as [[contact lenses]],<ref name="pmid14742616">{{cite journal |author=Biousse V, Tusa RJ, Russell B, ''et al'' |title=The use of contact lenses to treat visually symptomatic congenital nystagmus |journal=J. Neurol. Neurosurg. Psychiatr. |volume=75 |issue=2 |pages=314–6 |year=2004 |month=February |pmid=14742616 |doi= |url=http://jnnp.bmj.com/cgi/pmidlookup?view=long&pmid=14742616}}</ref> drugs, [[surgery]], and [[low vision]] [[Rehabilitation (neuropsychology)|rehabilitation]] have also been proposed.
Clinical trials of a surgery to treat nystagmus (known as tenotomy) concluded in 2001. Tenotomy is being performed regularly at the University of Pittsburgh Children's Hospital and by a handful of surgeons around the world. The surgery developed by Louis F. Dell'Osso Ph.D aims to reduce the eye shaking (oscillations), which in turn tends to improve visual acuity.
===Research===
Several universities are researching nystagmus and are looking for volunteers to take part in research activities.
==Izvori==
{{izvori}}
==Vanjske poveznice==
* [http://www.nystagmus.org American Nystagmus Network] — US-based support organisation
* [http://www.nystagmusnet.org/Research.htm Current UK Research Projects]
* [http://www.nystagmusnet.org Nystagmus Network UK] — UK-based support organisation
* [http://www.nystagmus.co.uk nystagmus.co.uk] — a teenager's experiences of nystagmus and a friendly forum
{{Patologija oka}}
[[Kategorija:Bolesti i poremećaji oka]]
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