Optic Neuritis

Question 1

Definition of optic neuritis

Answer 1

Is the inflammation of the optic nerve

Question 2

Aetiology of optic neuritis

Answer 2

• Most COMMON form is idiopathic optic neuritis:
◦ This is a primary demyelinating disease that can occur in isolation or as a part of MS (optic neuritis usually first symptom of MS)

• Likely environmental trigger is a virus (e.g EBV)
• Can also be seen in SLE, sarcoidosis, syphilis etc

Question 3

Pathophysiology of optic neuritis

Answer 3

• Optic neuritis and MS have the same pathophysiology and are thought to have autoimmune mechanisms triggered by environmental factors (e.g virus)
• Would lead to demyelination, axonal loss etc

Question 4

History and examination of optic neuritis

Answer 4

• Peri-orbital/retro-ocular pain: pain is EXACERBATED by EYE MOVEMENTS
• Typically unilateral
• Loss of visual acuity: loss of central vision (central scotoma), reaches worst point in 1-2 weeks
• Colour desaturation/loss of colour vision
• Relative afferent papillary defect (RAPD)
• Optic disc swelling
• MS symptoms:

Question 5

Risk factors for optic neuritis

Answer 5

• 30-50 years old
• Female
• White

Question 6

Investigations for optic neuritis

Answer 6

• MRI of optic nerves/brain: can diagnose optic neuritis. Would see swelling of optic nerve and white matter lesions in MS

Question 7

Repayment of optic neuritis

Answer 7

1) Methylprednisolone: high dose corticosteroid treatment (should ideally be started within 48 hours of symptom onset). Should recover in 4-6 weeks
May need gastroprotection with PPI

Question 8

Prevention and prognosis of optic neuritis

Answer 8

• Reduce environmental triggers of optic neuritis and MS: avoid smoking, adequate vitamin D exposure

• Recovers over weeks or months
• Visual prognosis is good, with very few having permanent reduced visual acuity
• Risk of recurrence and risk of conversion to MS (depends on abnormal MRI)

Question 9

Complications of optic neuritis

Answer 9

• MS
• Recurrence