Optic Neuritis

Basics

Description

  • Optic nerve dysfunction due to an inflammatory process, commonly associated with myelin destruction, leading to acute vision loss
  • Highly associated with multiple sclerosis (MS); presenting feature in 15–20% of MS patients
  • Grouped by site of inflammation:
    • Papillitis: Inflammation of the optic disk
    • Retrobulbar 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

Etiology

  • Idiopathic:
    • Most common
    • Single isolated events
  • MS:
    • 20–50% of patients with optic neuritis
    • Likely genetic component
      • High prevalence of A23, B7, and DR2 HLA alleles in patients with optic neuritis
  • Viral infections:
    • Chicken pox
    • Measles
    • Mononucleosis
    • HSV and HZV
    • Encephalitis
  • Postviral optic neuritis:
    • Usually occurs 4–6 wk after a nonspecific viral illness
  • Granulomatous inflammation:
    • TB
    • Syphilis
    • Sarcoidosis
    • Cryptococcal infection
  • SLE
  • HIV:
    • Cytomegalovirus
    • Toxoplasmosis
    • Histoplasmosis
    • Cryptococcus
  • Lyme disease
  • Contiguous inflammation of meninges, orbit, sinuses, and intraocular inflammation
  • Drug induced:
    • Amiodarone
    • Ethambutol
    • Tamoxifen

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