Optic disc swelling

Question 1

What is the optic disc?

Answer 1

Head of the optic nerve which can be seen clinically
The rest of the optic nerve extends proximally towards the chasm
The optic nerve is shorter in hypermetropic eyes and longer in myopic eyes.

Question 2

How can you describe the optic disc?

Answer 2

Contour: borders should be well defined, disc may be oval in astigmatism eyes and large in myopic eyes

Colour: Should be pink yellow with a pale centre, the disc colour is pale in optic atrophy

Cup: disc has a physiological cup which lies centrally and should occupy 1/3 of the disc. Cup widening and deepening occurs in glaucoma.

Question 3

What are causes of disc swelling?

Answer 3

Papilloedema
Malignant hypertension
Cavernous sinus thrombosis
Optic neuritis
Cranial SOL
Optic neuropathy
Central vein occlusion
Opague myelinated nerve fibres
Disorders of the nerve sheath

Question 4

What is papilloedema? How does it present?

Answer 4

Swelling of the optic disc caused by RICP
Always bilateral but not necessarily symmetrical

Symptoms of RICP - headache worse in morning, centred in frontal region and aggravated by bending down
Nausea/vomiting
CNXI palsy
Transient visual obscurations

Question 5

What investigations in papilloedema?

Answer 5

MRI with contrast
CT head
for intracranial SOL
Measure BP - malignant hypertension, idiopathic intracranial HTN in young obese women
LP if neuropathy imaging is norma (no risk of coning) to establish pressures and analyse CSF

Question 6

What is psuedopapilloedema?

Answer 6

Disc margins are blurred and disc appears elevated.
Usually benign and associated with hypermetropia ± astigmatism or tilted discs.
Cup may be absent but there is no true oedema and veins are of normal size and pulsate (due to nearby artery)
Treat as papilloedema until otherwise proven

Flueorescence angiography and US to distinguish

Question 7

What is diabetic papillopathy?

Answer 7

Mild visual impairment, optic disc swelling and features of diabetic retinopathy

Question 8

What are optic nerve head drusen?

Answer 8

Multiple hyaline bodies extending beyond the disc margins
Abnormal branching of retinal vessels is often present
Nerve head is usually small
If the hyaline material is buried in the disc substance, especially if a field defect is present.

FosterKennedy syndrome: optic atrophy in contralateral eye from meningioma of optic canal.