optic neuritis

Question 1

causes?

Answer 1

multiple sclerosis: the commonest associated disease
diabetes
syphilis

Question 2

features?

Answer 2

unilateral decrease in visual acuity over hours or days
poor discrimination of colours, ‘red desaturation’
pain worse on eye movement
relative afferent pupillary defect
central scotoma

Question 3

ix?

Answer 3

MRI of the brain and orbits with gadolinium contrast is diagnostic in most cases

Question 4

mx?

Answer 4

high-dose steroids
recovery usually takes 4-6 weeks

Question 5

prognosis?

Answer 5

MRI: if > 3 white-matter lesions, 5-year risk of developing multiple sclerosis is c. 50%