DESCRIPTION 
- Optic nerve dysfunction due to an inflammatory process, commonly associated with myelin destruction
- Highly associated with multiple sclerosis (MS); presenting feature in 15–20% of MS patients
- Grouped by site of inflammation:
- 5 yr risk for clinically definite MS following optic neuritis:
- Normal MRI—16%
- > 3 lesions on MRI—51%
- Recurrence is seen in 35% of patients.
RISK FACTORS
Genetics
High prevalence of A23, B7, and DR2 HLA alleles in patients with optic neuritis:
- Especially those that progress to clinically definite MS
ETIOLOGY
- Idiopathic:
- Most common
- Single isolated events
- MS:
- 20–50% of patients with optic neuritis
- Viral infections:
- Postviral optic neuritis:
- Usually occurs 4–6 wk after a nonspecific viral illness
- Granulomatous inflammation:
- SLE
- HIV:
- Lyme disease
- Contiguous inflammation of meninges, orbit, sinuses, and intraocular inflammation
- Drug induced:
[Outline]
SIGNS AND SYMPTOMS
- Vision loss and pain most common symptoms
- Visual loss occurring over days (rarely over hours), peaks in 1–2 wk:
- Adults usually unilateral (70%)
- Bilateral visual loss more common in children
- Retrobulbar pain: Increased with movement of the affected eye
- Light, color vision, and depth perception loss more pronounced than visual acuity loss
- Afferent pupillary defect almost always occurs in unilateral cases if other eye is healthy.
- Visual field defects:
- Usually characterized by central scotoma
- Deficits resolve by 1 yr in 56% of patients, and 73% resolve by 10 yr
- Funduscopic exam usually reveals either swollen (papillitis) or normal disk
- Uhthoff sign:
- Visual deficit occurring with exercise or increased body temperature
- Unusual sign seen occasionally
History
- Age (typically women 18–45 yr)
- Pain on eye movement
- Speed of onset of symptoms
- Associated symptoms
- Previous episodes
- Family history of optic neuritis, MS
Physical Exam
- Check BP.
- Complete ophthalmologic and neurologic exam, especially assessment of:
- Pupillary function
- Afferent pupillary defect
- Visual field defect
- Color vision (Ishihara color plates)
- Evaluation of the vitreous body for cells
- Dilated retinal exam (swollen optic disk)
DIAGNOSIS TESTS & INTERPRETATION
Lab
- CBC
- ESR
- Rapid plasma reagin, fluorescent treponemal antibody-absorption (FTA-ABS)
- Lyme titer
- Antinuclear antibody
- Purified protein derivative
- HIV
Imaging
- CXR for TB, sarcoid
- CT scan or MRI of brain and orbits:
- Inflammation of the retrobulbar optic nerve during the acute phase may appear as enlargement, thus falsely raising the issue of an optic nerve mass.
- Optic nerve inflammation is seen in 95% of gadolinium-enhanced MRIs.
- Visual field testing (preferably automated testing, such as Octopus or Humphrey)
DIFFERENTIAL DIAGNOSIS
- Acute papilledema
- Ischemic optic neuropathy
- Severe systemic hypertension
- Intracranial tumor compressing the afferent visual pathway
- Orbital mass compressing the optic nerve
- Toxic or metabolic neuropathy:
- Leber hereditary optic atrophy
Pediatric Considerations
In children, infectious and postinfectious causes should be considered.
Geriatric Considerations
In patients > 50 yr, ischemic optic neuropathies (e.g., diabetes and giant cell arteritis) are more common, and appropriate workup should be obtained.
[Outline]
ED TREATMENT/PROCEDURES
- Early ophthalmologic and neurologic consultations
- IV steroid pulse followed by oral steroids:
- Recommended for those with ≥2 demyelinating lesions on MRI without a prior history of MS or optic neuritis, or severe vision loss
- Decreases recurrence and progression to MS over 2 yr and shortens duration of visual impairment, but does not affect visual outcome at 1 yr nor rate of progression at 5 yr
- Treatment should be individualized for those with 1 lesion on MRI.
- Oral steroids used alone increases recurrence and should be avoided.
MEDICATION
Methylprednisolone: 250 mg IV q6h for 3 days, followed by oral prednisone (1 mg/kg/d) for 11 days with subsequent 4 day taper
[Outline]
DISPOSITION
Admission Criteria
- Bilateral vision loss
- If other sources of acute vision loss cannot be ruled out
- IV steroid pulse treatment needed
Discharge Criteria
- Unilateral visual impairment
- Good home support systems
- Neurology and ophthalmology follow-up arranged
Issues for Referral
Referral for interferon β-1a treatment as outpatient for high-risk patients (those with ≥2 demyelinating lesions on MRI):
- Reduces progression to MS
FOLLOW-UP RECOMMENDATIONS
Needs Ophthalmology referral
[Outline]
- Abou Zeid N, Bhatti MT. Acute inflammatory demyelinating optic neuritis: Evidence-based visual and neurological considerations. Neurologist. 2008;14:207–223.
- Balcer LJ. Clinical practice. Optic neuritis. N Eng J Med. 2006;354:1273–1280.
- Gal RL, Vedula SS, Beck R. Corticosteroids for treating optic neuritis. Cochrane Database Syst Rev. 2012;4:CD001430.
- Germann CA, Baumann MR, Hamzavi S. Ophthalmic diagnoses in the ED: Optic neuritis. Am J Emerg Med. 2007;25(7):834–837.
- Kale N. Management of optic neuritis as a clinically first event of multiple sclerosis. Curr Opin Ophthalmol. 2012;23:472–476.
- Kinkel RP, Kollman C, O'Connor P, et al. IM interferon beta-1a delays definite multiple sclerosis 5 years after a first demyelinating event. Neurology. 2006;66:678–684.
- Morrow MJ, Wingerchuk D. Neuromyelitis optica. J Neuroophthalmol. 2012;32:154–166.
See Also (Topic, Algorithm, Electronic Media Element)
Visual Loss
The author gratefully acknowledges Vinh D. Ngo's contribution for the previous edition of this chapter.