Nystagmus

Revision as of 15:55, 12 August 2018 by Josgood (talk | contribs) (Acquired Nystagmus)

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 locked when the head is in motion
  • Nystagmus is an aberration in this stabilization of the ocular muscles when in motion

Clinical Features

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

Differential Diagnosis

Congenital Nystagmus

  • Optic nerve hypoplasia
  • Macular disease
  • Noonan syndrome

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.