Optic Nerve Pathology

Question 1

what are the causes of optic neuritis?

Answer 1

• MS
• Idiopathic
• Hereditary optic neuritis
• Parainfectious optic neuritis – measles, mumps, chickenpox, whooping cough and glandular fever
• Infectious optic neuritis – cat scratch fever, TB, lymes, cryptococcal meningitis in AIDS
• Autoimmune – sarcoidosis, SLE, PAN, granulomatosis with polyangiitis

Question 2

what is the pathophysiology of optic neuritis?

Answer 2

• inflammation of the optic nerve

* swelling and destruction of the myelin sheath

Question 3

what is optic papillitis?

Answer 3

optic neuritis affecting the head of optic nerve

Question 4

what is neuroretinitis?

Answer 4

optic neuritis of the optic disc and surrounding retina in macular area

Question 5

what is retrobulbar neuritis?

Answer 5

optic neuritis of the posterior part of the nerve

Question 6

what are the clinical features of

Answer 6

• Sub acute loss of vision (over a few days)
• Unilateral oss of acuity
• Washed out colours
• Dull ache on eye movements
• RAPD
• Enlarged blind spot
• Optic disc swelling

Question 7

what is the management of optic neuritis?

Answer 7

Methylprednisolone for 72 hrs then prednisolone for 11 days

B interferon

Question 8

what are the causes of papilloedema?

Answer 8

Tumour, haemorrhage, abscess, Idiopathic intracranial hypertension, liver failure, malignant hypertension, Meningitis, Arnold-Chiari malformation, aqueduct stenosis, Sinus thrombus, Hydrocephalus, Hypercapnia, Hypoparathyroidism and hypocalcaemia, vit A toxicity

Question 9

what is the pathophysiology of papilloedema?

Answer 9

Subarachnoid space around optic nerve continuous with brain

Raised ICP travels through subarachnoid space onto the optic nerve

Question 10

what is the consequence of raised ICP in papilloedema?

Answer 10

Causes interruption of aoplasmic flow and venous congestion

Causes oedema + accumulation of CSF

Question 11

what are the clinical features of papilledema?

Answer 11

• May be asymptomatic
• Transient bilateral obscuration
• Reduced vision
• Increased blind spot
• Systemic – headaches + nausea, tinnitus

Question 12

what are the fundoscopic features of papilloedema?

Answer 12

o	venous engorgement
o	loss of venous pulsation
o	blurring of the optic disc margin
o	elevation of optic disc
o	loss of the optic cup
o	Paton's lines
o	Chronic – swollen discs can become pale and atrophic

Question 13

what are patons lines?

Answer 13

concentric/radial retinal lines cascading from the optic disc
seen in papilloedema

Question 14

what is the fundoscopic features of chronic papilloedema?

Answer 14

swollen discs can become pale and atrophic

Question 15

what is the management of papilloedema?

Answer 15

• Treat as lesion until proven otherwise

* CT or MRI then lumbar puncture and CSF analysis