Optic neuritis Flashcards
What is Optic Neuritis?
Optic Neuritis (ON) is defined as inflammation of the optic nerve.
What is the most common cause of optic neuritis?
Multiple sclerosis.
What are the main symptoms of optic neuritis?
Vision loss, typically occurring over hours to days, often accompanied by eye pain.
What are the risk factors for optic neuritis?
Age 30 to 50 years, female sex, white ethnicity, HLA-DRB1*1501 genotype.
What are the clinical features of optic neuritis?
The classic triad includes visual loss, periocular pain, and dyschromatopsia (deficiency in the perception of colors).
What are the examination findings in optic neuritis?
Colour vision is significantly affected, with ‘red desaturation’ observed. Eye movements are painful, and there is a relative afferent pupillary defect.
What is the first line of treatment for optic neuritis?
Intravenous methylprednisolone.
What is the management of optic neuritis?
High-dose corticosteroids are used, with recovery typically taking 4-6 weeks.
What investigations are diagnostic for optic neuritis?
MRI of the brain and orbits with gadolinium contrast is diagnostic in most cases.
What is a relative afferent pupillary defect (RAPD)?
When testing pupillary reflexes with a swinging light, the pupil of the affected eye dilates as the light is swung from the unaffected eye to the affected eye.
What are the differential diagnoses for optic neuritis?
Sarcoidosis, vasculitis, anterior ischaemic optic neuropathy, post-viral demyelination.
What is the relationship between optic neuritis and multiple sclerosis?
Up to 50% of patients with MS will develop an episode of optic neuritis, while 20-30% of optic neuritis cases will be the first manifestation of MS.
What are the causes of optic neuritis?
Demyelinating lesions (most commonly multiple sclerosis), autoimmune disorders, and infectious conditions.
What is the prognosis for optic neuritis?
If MRI shows more than 3 white-matter lesions, the 5-year risk of developing multiple sclerosis is approximately 50%.
What is the typical presentation of optic neuritis?
Unilateral eye pain, reduced colour vision, and a relative afferent pupillary defect.
What is the management for chronic optic neuritis associated with NMOSD or MOGAD?
Continuation of corticosteroid treatment beyond the acute phase, often with oral prednisolone for several months, and possibly introducing a corticosteroid-sparing immunosuppressive agent.
