Optic neuritis

Question 1

What are the signs and symptoms of optic neuritis

Answer 1

Symptoms

· Acute vision loss (hours to days)

· Eye pain and worsening of this pain on movement of the eye

Signs

· RAPD

· Often presence of a central scotoma (but can have any pattern of unilateral retinal nerve fibre loss)

· Papillitis with hyperemia and swelling of disk (1/3rd of patients)

· Blurred optic disc margins

· Elevated optic nerve head

· Flashes of light in some patients

· Colour vision defect (or reduced ability to see red)

· Perivenous sheathing (exudation from inflammatory cells around blood vessels)

· Periphlebitis retinae

· Contrast Sensitivity reduced

Question 2

Why does optic neuritis occur?

Answer 2

. Occurs as a result of inflammatory responses destroying the myelin sheath in the optic nerve.
· Immune mediated response which is a result of T-cell activation leading to the release of inflammatory agents including cytokines

· The cause is usually idiopathic but may also be the initial presenting sign of multiple sclerosis

Question 3

What are the 4 different types of optic neuritis?

Answer 3

retrobulbar

Papillitis

Perineuritis

Neuroretinitis

Question 4

Retrobulbar optic disc appearance? Prevalence stat?

Answer 4

With normal optic disc appearance,

2/3 of cases are this type

Question 5

perineuritis optic disc appearance? what signs to look for?

Answer 5

Perineuritis, which involves the optic nerve sheath while the optic disc may or may not be swollen

Question 6

Signs to look for in neuroretinitis?

Answer 6

Neuroretinitis with optic disc oedema and macular star exudates.

Question 7

DDx’s to consider

Answer 7

Anterior Ischaemic Optic Neuropathy

· NAION (pain on motilities in 10% of patients, patients age >40 atleast)

· Scleritis

· Malignant hypertension

· Hypertensive retinopathy

· BRVO/CRVO

· Acute Angle closure

· Compressive optic neuropathy

· Cystoid macular oedema

· Retinal detachment

· Macula hole

· Leber’s Optic Neuropathy - Bilateral vision loss (inherited condition, which mostly occurs in young males)

• Main symptoms
• Blurring of vision
• Clouding of Vision
• Loss of colour vision
• Progressive Loss
• Can start in one eye then develop to the other eye

· Papillodema (normally no pain on motilities, minimal to no decrease in VA)

· Retrobulbar tumour

Question 8

Risk factors:

Answer 8

· Young patients aged 15-45 years

· Females are more frequently affected

Question 9

targetted history?

Answer 9

· Do you experience eye pain on movement?

· Do you experience washed out colour in one eye?

· Do you notice any blurry vision on one eye compared to the other?

· Do you have any headaches? Could be a sign of AION

· Is the pain in both eyes or one eye?

· How is your general health? Most cases of Optic neuritis are associated with Multiple Sclerosis

Question 10

exam plan?

Answer 10

· Vision

· Red Cap test: positive due to optic nerve head involvement

· Pelli-robson contrast sensitivity: usually decrease

· Pupil: Positive for RAPD

· Red Cap test, D-15: looking for acquired colour vision defect

· Ocular Motilities: pain on eye movement

· Tonometry – normal IOPs can rule out angle closure

· Gonioscopy: wide anterior chamber angle can rule out acute angle closure

· Dilated Fundus Examination looking at optic nerve head oedema, myelination, macular oedema, infectious retinopathy

· OCT - macula oedema, optic disc swelling

· Visual fields: often central defect, but can be nay pattern of unilateral retinal nerve fibre loss (particularly important in retrobulbar optic neuritis

· MRI - To investigate the presence of MS

· Lumbar Puncture - To investigate the presence of MS by taking a sample of cerebrospinal fluid

Question 11

Management of optic neuritis?

Answer 11

Immediate Management

· Referral to neuro ophthalmologist

· If visual acuity is <6/12 recommended treatments as per Optic Neuritis Treatment Trial (ONTT) is intravenous methylprednisolone (1g/day x 3), followed by oral prednisolone 1mg/kg for 11 days

· Intravenous steroids (IV methylprednisolone) treatment is recommended when 3 or more signal abnormalities are present on MRI and reduces risk of developing MS by 2 years (Optic Neuritis Treatment Trial)

· Recovery of visual functions in ON is observed spontaneously within 2-3 weeks in more than 80% of patients without treatment

Long-term management

· Most patients regain vision over one month, but often report persisting reduction in the quality of vision

· There is an associated risk of developing demyelinating disease (most commonly multiple sclerosis), especially if other neurologic symptoms and signs are present

Question 12

Systemic associations?

Answer 12

MS or demyelination (ret or pap)
sinus related e.g ethmoiditis (ret) 
Lyme disease (ret or neu)
Viral infections (pap)
syphilis (pap or neu)
cat scratch fever (neu)

Question 13

What is uhthoff’s sign?

Answer 13

worsening of symptoms with exercise or increase in body temperature. A key signs of optic neuritis.