That optic disc doesn’t look right…

Optic neuritis — papillitis is seen on fundoscopy.

The history and MRI findings are suggestive of an underlying diagnosis of new onset multiple sclerosis.

The patient is typically female and aged between 18 and 45 years. Check for:

• Painless loss of vision over hours to days, which may be subtle or profound, with a nadir at about 1 week. Determine the rapidity of onset.
• Reduced visual acuity, colour and contrast vision may occur
• Usually it is unilateral, but can be bilateral
• There may have been previous episodes
• There may be orbital pain associated with eye movements
• Other focal neurological symptoms may be present (e.g. paraesthesiase)
• features suggestive of an underlying cause (see Q4), e.g. history of multiple sclerosis

• Visual acuity — decreased
• Colour vision — decreased
• Visual fields — patchy defects may be present, often arcuate or central
• Pupils — a Marcus-Gunn pupil (a relative afferent pupilary defect or RAPD) may be present.
• Fundoscopy — usually normal (retrobulbar optic neuritis — “neither the patient nor the doctor sees anything!”), papillitis may be present (see below for a comparison with papilloedema).
• Neurological examination — assess for focal neurological defects.

• multiple sclerosis
• familial
• idiopathic
• inflammation
  • viral — e.g. infectious mononucleosis, herpes zoster, viral encephalitischildhood infections or vaccinations — e.g. measles, mumps, chickenpoxGranulomatous inflammations — e.g. tuberculosis, syphilis, sarcoidosis, cryptococcusContiguous inflammation of the meninges, orbit, or sinuses.

The differential includes optic neuropathies such as:

• toxic optic neuropathy — e.g ethambutol, chloroquine, nicotine, alcohol
• metabolic optic neuropathy — vitamin B12 deficiency
• ischemic optic neuropathy — diabetes mellitus, giant cell arteritis, atherosclerosis
• compressive optic neuropathy — e.g. orbital tumour, intracranial mass

Both of these are occasionally present in optic neuritis:

• Pulfrich phenomenon — altered perception of moving objects
• Uhthoff sign — worsening of optic neuritis symptoms with exercise or increase in body temperature

There is no role — if you’re going to give steroids, give them IV!

There is an increased risk of optic neuritis recurrences in patients treated with oral prednisone.

Steroid therapy has been found to:

• reduce the risk of initial progression from optic neuritis to clinically definite multiple sclerosis for 3 years, but had no effect at 5 years.
• increases rate of vision return (at 1 and 3 weeks) but does not improve the final visual outcome (at 8 weeks) or alter the frequency of recurrences.

• Urgent ophthalmology referral.
• consider FBC, ESR, CRP and work up of possible inflammatory/ infectious causes.
• consider MRI — especially if atypical or a first episode, usually in consultation with the ophthalmology or neurology service.

In a first episode of optic neuritis or a patient who has not been diagnosed with multiple sclerosis:

• A 14 day course of steroids starting with methylprednisolone 1 g/day IV for 3 days is given if there is any evidence of demyelination on MRI, and may be given even if the the MRI is negative.

Patients known to have multiple sclerosis or have had previous optic neuritis are not treated with steroids and are observed.

About 30%.

• Beck RW, Cleary PA, Trobe JD, Kaufman DI, Kupersmith MJ, Paty DW, Brown CH. The effect of corticosteroids for acute optic neuritis on the subsequent development of multiple sclerosis. The Optic Neuritis Study Group. N Engl J Med.  1993 Dec 9;329(24):1764-9.  PMID: 8232485.
• The 5-year risk of MS after optic neuritis. Experience of the optic neuritis treatment trial. Optic Neuritis Study Group. Neurology. 1997 Nov;49(5):1404-13. PMID: 9371930.
• Patel V, Oetting TA. Optic Nerve Drusen: 19 year-old female with blurred vision. EyeRounds.org
• Sellebjerg F, Nielsen HS, Frederiksen JL, Olesen J. A randomized, controlled trial of oral high-dose methylprednisolone in acute optic neuritis. Neurology. 1999 Apr 22;52(7):1479-84. PMID: 10227638.
• Ehlers JP, Shah CP, Fenton GL, Hoskins EN. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease Lippincott Williams & Wilkins
• NSW Statewide Opthalmology Service. Eye Emergency Manual — An illustrated Guide. [Free PDF]
• Pulfrich C. Die stereoskopie im Dienste der isochromen und heterochromen photometrie. Die Naturwissenschaften 1922;10: Heft 25, 553–64
• O’Doherty M, Flitcroft DI. An unusual presentation of optic neuritis and the Pulfrich phenomenon. J Neurol Neurosurg Psychiatry. 2007 Aug; 78(8): 906–907. [PMC2117749]
• Uhthoff W. Untersuchungen über die bei der multiplen Herdsklerose vorkommenden Augenstörungen. Archiv für Psychiatrie und Nervenkrankheiten. 1890;21: 55-116 and 303-410.