Neuro - opthalmology Flashcards
How to test for defects in the optic nerve
RAPD - relative afferent pupillary defect
- swinging light test
Causes of afferent pupillary defects
Optic neuritis - younger patients with MS
GCA - older patients generally
Retinal artery occlusion
Trauma
Tumours
Retinal detachment
Which ocular muscles does CN III innervate
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
Which ocular muscles does CN IV innervate
Superior oblique
Which ocular muscles does CN VI innervate
Lateral rectus
3rd cranial nerve palsy presentation
Ptosis - superior levator palpebrae muscle
Down and out position
Binocular diplopia
Dilated pupil
Signs of a 3rd nerve palsy
Head tilt
Wrinkles on forehead as lifting frontalis muscle to compensate for the ptosis
Causes of a 3rd nerve palsy
Diabetes
HTN
Posterior communicating artery aneurysm - compresses Space occupying lesion Raised ICP Trauma GCA Congenital Demyelinating disease such as MS
What condition must be ruled out in a 3rd nerve palsy
Posterior communicating artery aneurysm - MR angiogram
Differentials for a 4rd nerve palsy
Myasthenia gravis
Horner’s syndrome
Thyroid eye disease
Internuclear ophthalmoplegia
4th nerve palsy presentation
Up and in
Diplopia when reading - vertical biocular diplopia
6th nerve palsy presentation
Diplopia when looking to side of affected eye - horizontal binocular diplopia
Pathophysiology of papilloedema
Swollen optic nerve head
How does papilloedema present
Normal with headache due to raised ICP
May have nausea or vomiting
Causes of papilloedema
Raised ICP due to
- space-occupying lesion
- trauma
- haemorrhage
- idiopathic intracranial haemorrhage
Risk factors for papilloedema
High BMI
Women
Contraceptive pill
What investigation should be done for papilloedema
MR venogram - rule out dural venous sinus thrombosis
Optic neuritis presentation
Defect on RAPD
Decreased red saturation
Larger blind spot
Pain with eye movements
Treatment of optic neuritis
Steroids
Causes of optic neuritis
Autoimmune demyelination - MS, sarcoidosis
Infection
History for neuro ophthalmology
Eye defect
Limb weakness Speech issues Walking and gait Nerve sensations Headache
Branches of the oculomotor nerve and what they supply
Superior branch - levator palpebrae superioris and superior rectus
Inferior branch - IR, MR, IO
Pupil involvement of a 3rd nerve palsy
Indicative of a compressive aetiology as the outer nerve fibres innervate the ciliary body with parasympathetic innervation
Investigations for a third nerve palsy
Orthoptic assessment Bloods - FBC, U+Es, LFTs, CRP BP CT head - SOL MRA - PCA aneurysm Biopsy - GCA MRI - MS
