Optic Neuritis

Question 1

What is optic neuritis?

Answer 1

inflammation of optic nerve

Question 2

What can optic neuritis involve?

Answer 2

retobulbar (retrobulbar neuritis) or the intrabulbar (papillitis) portion of the optic nerve or both

Question 3

What is the most common form of ON?

Answer 3

idiopathic

Question 4

What is idiopathic ON?

Answer 4

an inflammatory optic neuropathy in absence of evidence of systemic inflammatory disease

Question 5

What can ON suggest?

Answer 5

• can occur in isolation

- or be a manifestation (first one) of MS

Question 6

What are the symptoms and signs of optic neuritis?

Answer 6

1. Peri-orbital/retro-ocular pain
2. Loss of visual acuity with scotoma
3. Colour desaturation/loss of colour vision
4. Relative afferent papillary defect (RAPD)

Question 7

What are possible DDx of optic neuritis?

Answer 7

1. Lyme disease
2. Syphillus
3. HIV infection
4. Varicella-zoster SLE
5. Giant cell arteritis
   Etc

Question 8

What investigations do you do for ON?

Answer 8

1. MRI of optic nerve
2. FBC
3. ESR
4. CRP
5. VDLR
6. NMO antibody and anti MOG antibody
7. Uric acid
8. Serum ACE
9. ANA

Question 9

What would MRI of optic nerve show?

Answer 9

1. swelling of optic nerve
2. enhancement in optic nerve
3. white matter lesions in patients with multiple sclerosis (MS) or at risk of MS

Question 10

What would FBC show?

Answer 10

high WBC in infection

Question 11

What would ESR show?

Answer 11

high in giant cell arteritis

Question 12

What would CRP show?

Answer 12

high if infection

Question 13

What would VDLR show?

Answer 13

positive in syphillus

Question 14

What could early intervention of optic neuritis be?

Answer 14

e.g. interferon-beta and glatiramer acetate which can reduce risk of conversion to MS

Question 15

What is the 1st line acute treatment for idiopathic ON?

Answer 15

• plus dose methylprednisolone

- high-dose oral or IV corticosteroid treatment

Question 16

What should not be used in acute treatment of idiopathic ON?

Answer 16

low to medium dose oral corticosteroids alone should not be used in treatment of idiopathic acute ON

Question 17

What is the treatment for ongoing ON?

Answer 17

immunosuppressive treatment

Question 18

What are possible complications of ON?

Answer 18

1. Development of MS
2. Recurrent ON
3. Chronically reduced visual acuity

Question 19

What is normal epid for optic neuritis?

Answer 19

Female 20-40 yo

Question 20

How common is optic neuritis?

Answer 20

Most common optic nerve disease to affect young people

Question 21

What is the patho of optic neuritis?

Answer 21

Inflammatory demyelination of optic nerve

Question 22

What are causes of optic neuritis?

Answer 22

1. Multiple sclerosis: can be presenting manifestation of MS
2. Infectious
3. Drugs

Question 23

What infections can cause optic neuritis?

Answer 23

• viral encephalitis
• sinusitis
• meningitis

Question 24

What drugs can cause optic neuritis?

Answer 24

1. quinine
2. arsenic
3. ethambutol

Question 25

What are symptoms for optic neuritis?

Answer 25

1. Vision loss: scrotomas to complete vision loss
2. Hours to days
3. Decreased visual acuity
4. Pain: worse on movement
5. Reduced colour vision
6. Usually unilateral can be bilateral

Question 26

What is key investigation for optic neuritis and why?

Answer 26

• Gadolinium-enhanced MRI of the orbit and brain
  1. May show enlarged optic nerve
  2. Helps diagnose multiple sclerosis too