Neuro-ophthalmology - Conditions Flashcards
What are the common signs of optic nerve dysfunction?
Decrease in visual acuity
Dyschromatopsia - visual colour impairment
Visual field defects
Diminished contract sensitivity
Relative afferent pupillary defect (RAPD)
What can cause optic neuritis?
Demyelinating diseases e.g. MS
Infections
Clinical features of MS
Sensory loss - numbness
Spinal cord symptoms - muscle cramping & weakness
Autonomic features - bladder, bowel & sexual dysfunction
Cerebellar - tremor + dysartyhria + ataxia (Charcot’s triad)
L’hermitte sign - electrical shock on neck flexion
Uhthoff phenomenon - worsening of symptoms due to increase in temp e.g. hot shower
Optic neuritis - USUALLY IS THE PRESENTING COMPLAINT
Nystagmus
Ix Optic neuritis and what you will see if you do the investigations in an affected pt
MRI - demyelinating plaques
Lumbar puncture - Oligoclonal bands
Tx Optic neuritis
IV methylprednisolone + Oral prednisolone
Aetiology of Anterior Ischaemic Optic Neuropathy (AION)
Damage to the optic nerve as a result of ischaemia
Cause of NON-arteritic AION
Occlusion of short posterior ciliary artery due to: Hypertension Diabetes Sleep apnoea Optic disc anomaly
Cause of arteritic AION
Giant cell arteritis - this occludes the short posterior ciliary artery
What is the difference in vision loss between arteritic and non-arteritic AION ?
Arteritic = painful Non-arteritic = painless
What happens to the optic disc in arteritic/non-arteritic AION?
Arteritic - Chalky-white diffuse swollen disc
Non-arteritic - disc swelling
Ix of arteritic AION
ESR, CRP, temporal artery biopsy
Tx of arteritic/non-arteritic AION
Arteritic - high dose systemic steroid IV methylprednisolone or oral prednisolone + aspirin
Non-arteritic - treat cause
Aetiology of papilloedema
Optic disc swelling secondary to elevated intracranial pressure
Clinical features of papilloedema
Elevated ICP symptoms - headache, N&V
Transient visual loss
Enlarged blind spot
Optic disc signs - hyperaemia and blurred margins of optic disc (early)
Swelling and elevation of the whole optic disc with peripaillary splinter haemorrhages (late)
Aetiology of Horner’s syndrome
lesion in the sympathetic pathway
3 classic symptoms of Horner’s syndrome
Ptosis
Miosis
Ipsilateral anhidrosis
Causes of Horner’s syndrome
Stroke
Pancoast tumour
Carotid artery dissection
Cluster headache
Ix Horner’s syndrome
Give apraclonidine - a receptor-1 agonist causing little pupillary dilation in horner’s pupil but will significantly dilate the unaffected eye
CT/MRI used to confirm any tumours or artery dissection
What is Adie’s Pupil?
Loss of postganglionic parasympathetic innervation to the iris sphincter and ciliary muscle
Unilateral
Occurring in young females
Clinical features of Adie’s pupil
Anisocoria (affected pupil is larger)
Blurring on near vision
Light reflex absent & Near reflex is slow
Ix Adie’s pupil
Slit lamp
0.125% topical pilocarpine in both eyes - adie’s pupil constricts while normal pupil doesn’t
What is Argyll Robertson pupil?
Bilateral irregular small pupils
Both pupils don’t react to light - they do constrict normally on accomadation
Pilocarpine does cause constriction of pupils. T/F?
F. It does NOT. (opposite of adie’s)
Clinical feature of 3rd nerve palsy
Ptosis
Down and out eye
Ophthalmoplegia (only abduction of eye is fully normal)
Dilated pupil and accommodation abnormality
What medical issues could cause 3rd nerve palsy?
Diabetes and Hypertension
Clinical features of 4th nerve palsy?
Vertical diplopia - worse walking downstairs or looking down
Hypertropia
Depression of eye limited
Head tilt
Clinical features of 6th nerve palsy?
Horizontal double vision - worse on looking at distant targets
Esotropia in primary position
Abduction is limited
Cause of 6th nerve palsy
Diabetes
Hypertension
Increased ICP
What is myasthenia gravis
Autoimmune disease of acetylecholine receptors at post-synaptic neuromuscular junctions
F>M
Affects voluntary muscles
Occular problems are usually the presenting complaint
Clinical features of myasthenia gravis
Ptosis - bilateral
Lid twitch
Diplopia
Weakness of muscles of facial expression
Ix Myasthenia
Ice test - ptosis improves after 2 mins
Antibodies - Anti-ACh receptor antibody and anti-muscle specific kinase (MUSK) antibody
Electromyography and muscle biopsy
Imaging of thorax - can reveal thymoma which is associated with myasthenia (tumour)
Tx Myasthenia Gravis
Pyridostigmine (anticholinesterase), steroids & immunomodulators
Surgery if thymoma present
Is neurofibromatosis autosomal dominant or recessive?
Dom
Clinical features of neurofibromatosis?
Neurofibromas
Café au lait spots
Axillary freckling
Ophthalmic features:
- Optic nerve glioma
- Bilateral lisch nodules (harmless, don’t affect vision)
- Plexiform neurofibromas of the eyelid - ‘bag of worm’ sensation
NF 2 is more common than NF 1? T/F
F. NF1 is more common
What is in the cavernous sinus and at what location within the sinus?
Lateral wall contains CN 3,4,5 (V1 ,V2)
Internal carotid artery & CN6 pass THROUGH the cavernous sinus
Clinical features and the reasoning behind them
Ptosis & ophthalmoplegia (paralysis of the muscles within or surrounding the eye) - due to compression of CN 3,4,6
Loss of corneal reflex - due to V1
Maxillary sensory loss - due to V2
Horner’s syndrome - due to involvement of internal carotid ocular sympathetics
Proptosis & periorbital swelling - due to increased venous pressure in the veins draining the orbit
Causes of cavernous sinus syndrome?
Infections Tumours Cavernous sinus thrombosis Internal carotid aneurysm Carotid-cavernous fistula
