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Optic Neuritis, Emergency Medicine

Basics

Description

- Granulomatous inflammation: - TB - Syphilis - Sarcoidosis - Cryptococcal infection

- 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

- 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)

  • 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:Papillitis: Inflammation of the optic diskRetrobulbar neuritis: Inflammation of the optic nerve proximal to the globe
  • 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 commonSingle isolated events
  • MS:20 " 50% of patients with optic neuritis
  • Viral infections:Chicken poxMeaslesMononucleosisHSV and HZVEncephalitis
  • Postviral optic neuritis:Usually occurs 4 " 6 wk after a nonspecific viral illness
  • Granulomatous inflammation:TBSyphilisSarcoidosisCryptococcal infection
  • SLE
  • HIV:CytomegalovirusToxoplasmosisHistoplasmosisCryptococcus
  • Lyme disease
  • Contiguous inflammation of meninges, orbit, sinuses, and intraocular inflammation
  • Drug induced:AmiodaroneEthambutolTamoxifen

Diagnosis

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 scotomaDeficits 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 temperatureUnusual 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 functionAfferent pupillary defectVisual field defectColor vision (Ishihara color plates)Evaluation of the vitreous body for cellsDilated 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:Heavy metal poisoningAnemiaMalnutritionEthanol/MethanolChloroquineEthambutolIsoniazid
  • Leber hereditary optic atrophy

In children, infectious and postinfectious causes should be considered.

In patients >50 yr, ischemic optic neuropathies (e.g., diabetes and giant cell arteritis) are more common, and appropriate workup should be obtained.

Treatment

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 lossDecreases 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 yrTreatment 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

Follow-Up

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 ²-1a treatment as outpatient for high-risk patients (those with ≥2 demyelinating lesions on MRI):

  • Reduces progression to MS

Followup Recommendations

Needs Ophthalmology referral

Pearls and Pitfalls

  • Rule out space-occupying lesions before making the diagnosis of optic neuritis.
  • Acute bilateral loss with a severe headache or diplopia should raise concern for pituitary apoplexy.
  • The true benefit of corticosteroids in the treatment of optic neuritis is unclear, and emergency physicians should consult with appropriate specialists to determine the local standard of practice.
  • Brain MRI is the most useful predictor of subsequent development of MS.

Additional Reading

  • 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. Ngos contribution for the previous edition of this chapter.

Codes

ICD9

  • 377.30 Optic neuritis, unspecified
  • 377.31 Optic papillitis
  • 377.32 Retrobulbar neuritis (acute)
  • 377.39 Other optic neuritis

ICD10

  • H46.00 Optic papillitis, unspecified eye
  • H46.9 Unspecified optic neuritis
  • H46.10 Retrobulbar neuritis, unspecified eye
  • H46.8 Other optic neuritis

SNOMED

  • 66760008 Optic neuritis (disorder)
  • 73221001 Optic papillitis (disorder)
  • 230507009 Retrobulbar neuritis (disorder)
  • 432521000124106 Bilateral optic neuritis (disorder)