Optic neuritis

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Background

  • Inflammatory, demyelinating condition of the optic nerve highly associated with MS
    • 50% will go on to develop MS
  • Presenting feature of MS in 15-20% of patients

Causes

Clinical Features

  • Acute, usually monocular, vision loss occurring over days (occasionally over hours)
    • May range from mildly reduced to no light perception whatsoever
  • Retro-orbital headache
  • Pain (esp with eye movement)
  • Loss of color vision out of proportion to loss of visual acuity
  • Pulfrich effect - swing object side to side like pendulum, but patient feels like the object is coming at them in elliptical fashion; suggestive of demyelination[1]

Differential Diagnosis

Acute Vision Loss (Noninflamed)

Emergent Diagnosis

Evaluation

Physical Exam

  • Red desaturation test
    • Have patient look with one eye at a dark red object
    • Test the other eye to see if the object looks the same color
      • Affected eye often will see the red object as pink or lighter red
  • Normal intraocular pressures
  • Normal slit lamp exam (no evidence of uveitis)
  • Afferent Pupilary Defect (APD)
  • Optic disc swelling and edema (papillitis)
    • Elevated optic nerve disk on ultrasound = papilledema
    • Increased ON sheath diameter > ~5mm measured 3mm behind globe on US[2]

Work-up

  • MRI of brain and orbits with gadolinium, plus fat suppression
  • CBC
  • CMP
  • ESR, CRP
  • RPR, FTABS
  • CXR
  • May consider LP to rule out neuromyelitis optica (Consult with neuro regarding CSF and serum studies):
    • Typically protein/glucose, gram stain/culture, cell count/differential
    • Plus angioconverting enzyme, IgG indices, myelin basic protein, oligoclonal bands
    • Plus SERUM IgG indices, oligoclonal bands, angioconverting enzyme, NMO antibodies

Disposition

  • Consult neuro and ophthalmology
  • Inpatient admission for IV methylprednisolone, 1 g QD x3 days

See Also

References

  1. O'Doherty M and Flitcroft DI. An unusual presentation of optic neuritis and the Pulfrich phenomenon. J Neurol Neurosurg Psychiatry. 2007 Aug; 78(8): 906–907.
  2. Shevlin C. Optic Nerve Sheath Ultrasound for the Bedside Diagnosis of Intracranial Hypertension: Pitfalls and Potential. http://www.criticalcarehorizons.com/optic-nerve-sheath-diameter-icp/
  • Petzold A et al. The investigation of acute optic neuritis: a review and proposed protocol. Nat Rev Neurol. 2014 Aug;10(8):447-58.
  • Voss E et al. Clinical approach to optic neuritis: pitfalls, red flags and differential diagnosis. Ther Adv Neurol Disord. 2011 Mar; 4(2): 123–134.