Nystagmus

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Introduction

 

Nystagmus is an involuntary back-forth, up-down, or rotating eye movement.

 

Nystagmus can also suggest problems with the vestibular system.

 

slow phase - deregulated vestibular stimulus cuases drift

fast phase - cortical correction (this is the direction of the nystagmus)

problem with vestibular input to eom system

 

paralytic nystagmus - right ear is busted

irritative nystagmus - right ear is overactive - slow drift to left, so right beating nystagmus

 

Can be caused by benign paroxysmal positional vertigo (BPPV)

 

The Case of...

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Differential Diagnosis

Can be caused by

Rotatory nystagmus

CN IV or brain stem problems

 

Direction-changing nystagmus

CN III and VI and cerebellum

 

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History and Physical Exam

  • history
  • physical exam

History

Physical Exam

It can be induced physiologically by turning the eyes far to one side: ask the person to follow a pen and ask them to hold the gaze for a few seconds at the end of the change.

or by injecting water into the ear canal.

 

caloric testing

  • cold water in the canal causes a change in temperature
  • COWS - cold opposite, warm same
  • cheap
  • can test each ear
  • can't do if there's a hole in the eardrum

rotation chair testing

  • tests both lateral canals
  • ask patients to look straight at you

 

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Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Diagnostic Imaging

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Management

 

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Pathophysiology

 

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Resources and References

 

 

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Topic Development

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