Neuro-opthalmology Flashcards
What are the differentials for optic disc swelling?
Optic neuritis
Papilloedema (has to be bilateral)
Malignant hypertension
Arteritic anterior ischaemic optic neuropathy
Non-arteritic anterior ischaemic optic neuropathy
How does optic neuritis present?
Produces a swollen disc and the margin is blurred with a pink colour and normal cup
blurring of vision and a dull ache, especially on eye movement
Vision will be reduced centrally along with para-central scotoma or an enlarged blind spot
If inflammation of optic nerve farther back will cause retrobulbar neuritis (no swelling of optic disc)
RAPD and a desaturation of red colour vision
Risk of blurring with exercise, or a tingling sensation in the fingers or toes
Risk of MS, MRI needed for repeat episode
How does papilloedema present?
Swelling of the optic discs due to increased intracranial pressure (therefore must be bilateral)
May be unilateral if patient has developed optic atrophy in one eye previously
Transient blurring of vision and headaches
Retinal signs: splinter haemorrhages, exudates, cotton wool spots, retinal folds
Enlarged blind spots and a gradual progressive field loss
Eventually irreversible atrophic changes
What is arteritic anterior ischaemic optic neuropathy (AION)?
inflammation of the arteries to the optic disc which causes infarction
giant cell/temporal arteritis where inflammation of the temporal arteries causes occlusion of the vascular supply to the optic nerve and it hence gets infracted
temporal headache, jaw claudication (due to jaw ischemia) and scalp tenderness (on affected side)
Loss of weight, myalgia
ESR and CRP raised
Visual loss is caused by an inflammatory infarction of the posterior ciliary artery
What is the management for arteritic anterior ischaemic optic neuropathy (AION)?
Urgent high dose steroid (1-1.5mg per kg but usually 80mg) treatment is needed or the other eye will go in 2- 3 weeks
temporal artery biopsy is needed within one week of starting treatment to give a conclusive diagnosis (giant cells)
Treatment should continue for at least 2 years
On fundoscopy the disk is pale/white and the margins are blurred- the cup is obliterated and will not be seen- the rest of the fundus may also have some pallor
How does non-arteritic anterior ischaemic optic neuropathy?
Caused by a swollen artery, usually due to atherosclerosis
This causes obliteration of the lumen of the posterior ciliary arteries and the optic nerve gets infracted
Swelling is not as gross as with giant cell arteritis and the visual impairment is usually not as extensive- usually only half the disc gets infracted (top or bottom)
ESR is not raised
50% of patients will be hypertensive and many other patients will be diabetic
No systemic symptoms
Treatment is low does aspirin
How does optic atrophy present?
Means the optic nerve is atrophic and pale
There is loss of the surface capillaries of the optic disc and it is associated with a RAPD
Anything that causes a disruption of the blood supply to the optic nerve, or compression of it, will produce optic atrophy
How does a third nerve palsy present?
Affects the SR, MR, IR, IO, levator palpebrae superioris and intraocular pupil muscles The SO and LR are spared so the eye will look down and out Ptosis, a dilated pupil (efferent defect) but no APD
How does a fourth nerve palsy present?
Affects the SO- eye is unable to look down and in on the affected side, hence vertical diplopia is most marked on looking down and in bilateral cases may occur with head injury
How does a sixth nerve palsy present?
Affects the LR- this causes an inability to abduct the affected eye so it may drift to the medial side
How does a seventh nerve palsy present?
Supplies the muscles of facial expression including those that close the eye
eye cannot be closed and tear coverage will be reduced- dry cornea and exposure keratitis
corneal sensation should be tested along with Bell’s phenomenon -
patient’s eyeballs roll up when eyes are closed to protect cornea (normal)
How does APD present?
no consensual or direct response
disruption of fibres travelling from the RGC to PTN and from the PTN to the same and contralateral sided EWN
the afferent pathway is from the retina up to the EWN- however pathology usually affects the retina or optic nerve
How does RAPD present?
Reduced light and consensual response, pupil dilates on the swinging light test:
will show maximal constriction in both eyes when shined on the good eye, and a slight dilation in both eyes when shined on the bad eye
similar to APD but is not complete so a minimal response will be noticed
How does Horner’s syndrome present?
lesion affecting the sympathetic supply to the eyes
The affected pupil is smaller than normal and there is some ptosis
pupil inequality is more pronounced in the dark
neck scar (pathology to sympathetic chain), partial ptosis and their eyes may appear to be sunken in (apparent enophthalmos)
alternatively the patient may have had the sympathetic chain disrupted by an apical lung tumour (Pancoast tumour)
What are argyll Robertson pupils?
Due to tertiary syphilis (neurosyphilis affecting the midbrain)
pupils are often small and irregular (both affected and maybe asymmetry between the two) and there is a sluggish response to light
Light-near dissociation and the patient may be blind from optic atrophy- this was usually seen in 60-70 year old patients but syphilis is now on the rise
Can present with uveitis
