Difference between revisions of "Nystagmus"

(Differential Diagnosis)
(Background)
 
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==Background==
 
==Background==
The "H in Space" test is a quick way to grossly evaluate the function of cranial nerves 2, 3, 4, and 6. However, further mechanisms for eye movement exist outside than the above mentioned for voluntary eye movement. Namely, the semicircular canals of the vestibules and the extraocular muscles of the eye function together physiologically to help control gaze locked when the head is in motion. Nystagmus is an aberration in this stabilization of the ocular muscles when in motion.
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*Nystagmus = involuntary eye movement
 +
*The semicircular canals of the vestibules and the extraocular muscles of the eye function together physiologically to help control gaze when the head is in motion
 +
*Nystagmus is an aberration in this stabilization of the ocular muscles when the head is in motion
  
 
==Clinical Features==
 
==Clinical Features==
Nystagmus is a rapid, uncontrolled, rhythmic oscillation of the eye. While most commonly this occurs side to side, it can also occur up and down, circularly, or in any direction.
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*Rapid, uncontrolled, rhythmic oscillation of the eye
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*May be horizontal, vertical, and/or rotary
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
 
===Congenital Nystagmus===
 
===Congenital Nystagmus===
* Optic Nerve Hypoplasia
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*Optic nerve hypoplasia
* Macular Disease
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*Macular disease
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*[[Eponyms (M-P)#Noonan's syndrome|Noonan syndrome]]
  
 
===Acquired Nystagmus===
 
===Acquired Nystagmus===
* Neurological damage
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*[[Head trauma]], [[tympanic membrane rupture]]
* Psychoactive drugs
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*[[Brain tumor]]
* [[Alcohol intoxication]]
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*[[Stroke]]
* [[Head trauma]]
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*Chiari malformation
* Brain tumor
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*[[Meniere's disease]], [[BPPV]], [[labyrinthitis]], [[Vestibular Neuritis]]
* [[Stroke]]
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*[[Multiple sclerosis]]
* [[Multiple sclerosis]]
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*[[Wernicke-Korsakoff syndrome]], [[thiamine deficiency]]
* Thalamic hemorrhage
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*Tox causes:
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**[[Alcohol intoxication]], [[benzodiazepines]], [[barbiturates]], [[GHB]]
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**[[Ketamine]], [[Phencyclidine]]
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**[[Amphetamines]], [[Ecstasy (MDMA) toxicity|MDMA]]
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**[[Marijuana]]
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**[[Lithium]]
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**[[Phenytoin]], [[fosphenytoin]], [[carbamazepine]], [[oxcarbazepine]], [[lacosamide]], [[gabapentin]]
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**[[Salicylates]], [[NSAID toxicity]]
  
 
==Evaluation==
 
==Evaluation==
While the "H in space" test may be the quickest way to assess for gross extraocular muscle dysfunction, the Caloric Reflex Test (also known as Vestibular Caloric Stimulation) is the best clinical test for the Vestibulo-Optic reflex. Water irrigated into the external auditory canal will exaggerate nystagmus if present. Furthermore, the temperature of the irrigated water will control the direction. Cold water will exaggerate a nystagmus to move contralaterally, and warm water will exaggerate a nystagmus to move ipsilaterally. This can be remembered by the mnemonic "COWS".
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*Differentiate monocular vs. binocular
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**Monocular suggests medial pontine stroke or medial longitudinal fasciculus damage
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**Look for contralateral [[internuclear opthalmoplegia]] (INO)
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*Differentiate between central versus peripheral lesions<ref>Bardorf CM et al. Acquired Nystagmus Clinical Presentation. Updated My 13, 2016. http://emedicine.medscape.com/article/1199177-clinical?src=refgatesrc1#b4.</ref>
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{| {{table}}
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| align="center" style="background:#f0f0f0;"|'''Central'''
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| align="center" style="background:#f0f0f0;"|'''Peripheral'''
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|-
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| Pure vertical, pendular, or rotary||Horizontal
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|-
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| Fast beat towards lesions||Fast beat away from lesion
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|-
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| Not relieved by gaze fixation||Relieved by gaze fixation
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|-
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| Cerebellar signs||No cerebellar signs
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|}
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===Optokinetic Drum Test===
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*Optokinetic reflex develops ~6 months of age
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*Slow pursuit of eyes towards direction of vertical bar movement with quick saccade towards the opposite side to find the next bar to fixate on
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*Abnormal in congenital nystagmus
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*In parietal or parietal-occipital lesions, optokinetic nystagmus is impaired when the drum is rotated towards side of lesion
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**See [https://www.youtube.com/watch?v=UJVFFqZJKGo OKN drum to the right]
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**See [https://www.youtube.com/watch?v=rKm04X-gd2I&list=PLhVpkuPiEu3btjvIlCckXow7PNf5WHdsN OKN drum to the left]
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==="H in space" Test===
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*Trace H in space
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===Caloric Reflex Test (also known as Vestibular Caloric Stimulation)===
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*The best clinical test for the Vestibulo-Optic reflex
 +
*Water irrigated into the external auditory canal will exaggerate nystagmus if present
 +
*Temperature of the irrigated water will control the direction.  
 +
**Cold water will exaggerate a nystagmus to move contralaterally
 +
**Warm water will exaggerate a nystagmus to move ipsilaterally
  
 
<big>'''COWS''': '''C'''old '''O'''pposite, '''W'''arm '''S'''ame.</big>
 
<big>'''COWS''': '''C'''old '''O'''pposite, '''W'''arm '''S'''ame.</big>
  
 
==Management==
 
==Management==
Stabilize patient and manage primary course of illness. If possible, reverse toxicology.
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Stabilize patient and manage primary cause of illness.
  
 
==Disposition==
 
==Disposition==
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==See Also==
 
==See Also==
 
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*[[Focal neurologic deficits]]
  
 
==External Links==
 
==External Links==
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<references/>
 
<references/>
  
[[Category:Symptoms]]
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[[Category:Symptoms]] [[Category:Neurology]]

Latest revision as of 14:22, 18 September 2019

Background

  • Nystagmus = involuntary eye movement
  • The semicircular canals of the vestibules and the extraocular muscles of the eye function together physiologically to help control gaze when the head is in motion
  • Nystagmus is an aberration in this stabilization of the ocular muscles when the head is in motion

Clinical Features

  • Rapid, uncontrolled, rhythmic oscillation of the eye
  • May be horizontal, vertical, and/or rotary

Differential Diagnosis

Congenital Nystagmus

Acquired Nystagmus

Evaluation

  • Differentiate monocular vs. binocular
    • Monocular suggests medial pontine stroke or medial longitudinal fasciculus damage
    • Look for contralateral internuclear opthalmoplegia (INO)
  • Differentiate between central versus peripheral lesions[1]
Central Peripheral
Pure vertical, pendular, or rotary Horizontal
Fast beat towards lesions Fast beat away from lesion
Not relieved by gaze fixation Relieved by gaze fixation
Cerebellar signs No cerebellar signs

Optokinetic Drum Test

  • Optokinetic reflex develops ~6 months of age
  • Slow pursuit of eyes towards direction of vertical bar movement with quick saccade towards the opposite side to find the next bar to fixate on
  • Abnormal in congenital nystagmus
  • In parietal or parietal-occipital lesions, optokinetic nystagmus is impaired when the drum is rotated towards side of lesion

"H in space" Test

  • Trace H in space

Caloric Reflex Test (also known as Vestibular Caloric Stimulation)

  • The best clinical test for the Vestibulo-Optic reflex
  • Water irrigated into the external auditory canal will exaggerate nystagmus if present
  • Temperature of the irrigated water will control the direction.
    • Cold water will exaggerate a nystagmus to move contralaterally
    • Warm water will exaggerate a nystagmus to move ipsilaterally

COWS: Cold Opposite, Warm Same.

Management

Stabilize patient and manage primary cause of illness.

Disposition

See Also

External Links

References

  1. Bardorf CM et al. Acquired Nystagmus Clinical Presentation. Updated My 13, 2016. http://emedicine.medscape.com/article/1199177-clinical?src=refgatesrc1#b4.