Disease Profiles: Neuro-Opthalmic Disease Flashcards
List 4 causes of visual field defects
Vascular disease - CVA
Space occupying lesion (SOL) e.g. pituitary tumour
Demyelination (MS)
Trauma - including surgical
What is sudden onset diplopia?
Patient has changed from having binocular single vision, seeing one image only, to a sudden onset manifest squint and diplopia (double vision)
Describe the clinical presentation of optic neuritis
Progressive unilateral visual loss
Pain behind eye, especially on movement
Colour desaturation
Central scotoma
Horizontal double vision with esotropia/exotropia on cover test suggests a problem with which ocular muscles?
Medial or lateral rectus
Describe the clinical presentation of a CN IV nerve palsy
Typically results in vertical diplopia when looking inferiorly, due to loss of the superior oblique’s action of pulling the eye downwards
Affected eye turned upward in primary position
What pathology would result in a bitemporal field defect?
Optic chiasm defect - pituitary tumour, craniopharyngioma, meningioma
Describe the findings on fundoscopy associated with optic atrophy
Pale optic disc
What investigation us used to detect a manifest squint (topia)?
Cover test
Name 3 causes of papilloedema
Space-occupying lesion
Problems with cerebral blood flow (e.g. malignant hypertension)
Problems with CSF (obstruction to circulation, overproduction, inadequate absorption)
What causes sudden onset diplopia?
New weakness of extra-ocular muscles
What would be the most likely cause of a painful CN III palsy?
Aneurysm
What pathology would result in a contralateral homonymous hemianopia (macula not spared)?
Optic tract defect - tumours, demyelination, vascular anomalies
Which cranial nerve supplies all extaocular muscles except superior oblique and lateral rectus?
CN III
What is non-arteric ischaemic optic neuropathy?
ION due to non-inflammatory disease of small blood vessels - vascular risk factors
What is the most common cause of internuclear opthalmoplegia in a younger patient?
MS
Name the cranial nerve which supplies the superior oblique
CN IV
Describe the findings on fundoscopy associated with ischaemic optic neuropathy
Pale, swollen disc
Name a common cause of bilateral optic disc swelling in young females
Swelling of the optic nerve due to increased intracranial pressure
Name a complication of chronic papilloedema
Chronic papilloedema can cause axon damage leading to optic atrophy → loss of visual function occurs and blindness may result
What pathology would result in a contralateral homonymous quadrantanopia (macula not spared)?
Optic radiation defect - tumours, demyelination, vascular anomalies
Define ischaemic optic neuropathy
Occlusion of the posterior ciliary arteries, resulting in infarction of the optic nerve head
What causes internuclear opthalmoplegia?
Injury/dysfunction in the medial longitudinal fasciculus (tract which acts as the central connection for the oculomotor nerve, trochlear nerve, and oculomotor nerve)
Describe the clinical presentation of a CN VI nerve palsy
Results in unopposed adduction of the eye (by the medial rectus muscle), resulting in a convergent squint or esotropia (eye turns inwards)
Patients typically present with horizontal diplopia which is worsened when they attempt to look towards the affected side
Name 4 causes of a CN VI nerve palsy
Microvascular
Raised intracranial pressure
Tumour
Congenital
What autoimmune disease can cause ischaemic optic neuropathy
Temporal (giant cell) arteritis - posterior ciliary arteries become affected and the wall becomes so inflamed/thickened that lumen becomes occluded
What pathology would cause unilateral visual loss?
Defect to the optic nerve - ishcaemic optic neuropathy, optic neuritis (commonly MS), tumours (meningioma, glioma, haemangioma)
What causes optic atrophy?
End stage that arises from damage to the optic nerve of any cause
Describe the findings on fundoscopy associated with papilloedema
Disc swelling (blurring)
How can CN III nerve palsy cause miosis?
Loss of parasympathetic fibres responsible for innervating to the sphincter pupillae muscle
Describe the prognosis of optic neuritis
Gradual recovery over weeks to months
How can CN III nerve palsy cause ptosis?
Due to a lack of innervation to levator palpebrae superioris
How might patients with IV palsies compensate for diplopia with variable head positioning?
Chin-down head posture is seen in bilateral CN IV palsy and contralateral head tilt is typically seen in unilateral CN IV palsy (common in children)
Describe the clinical presentation of a CN III nerve palsy
‘Down and out’ appearance of the affected eye due to unopposed action of both the lateral rectus and superior oblique muscles, which pull the eye inferolaterally
Can also cause ptosis and miosis
Define papilloedema
Swelling of the optic nerve due to increased intracranial pressure
What pathology would result in a contralateral homonymous hemianopia with macular sparing?
Occipital cortex defect - vascular disease (CVA), demyelination
Vertical double vision with hypertropia/hypotropia on cover test suggests a problem with which ocular muscles?
Superior oblique, superior rectus, inferior rectus, inferior oblique
Describe the pathophysiology of papilloedema
When intracranial pressure rises, the increased pressure is transmitted to the subarachnoid space and then onto the optic nerve
This causes interruption of axoplasmic flow and venous congestion → swollen discs
Describe the clinical presentation of papilloedema
Headache
Enlarged blind spot, blurring of vision, visual obscurations and loss of vision
N+V, especially if ICP rise is acute
List 5 causes of a CN III nerve palsy
Microvascular
Tumour
Aneurysm
MS
Congenital
What is the most common cause of internuclear opthalmoplegia in an older patient?
Generally have a vascular aetiology (stroke)
Name the cranial nerve which supplies the lateral rectus muscle
CN VI
Describe the clinical presentation of ischaemic optic neuropathy
Sudden visual loss
Usually painless
If associated with GCA - headache, scalp tenderness, enlarged temporal arteries
List 4 causes of a CN IV nerve palsy
Congenital decompensated
Microvascular
Tumour
Blunt head trauma can result in bilateral CN IV palsy
Describe the clinical presentation of internuclear opthalmoplegia
Impairment of adduction
Define internuclear opthalmoplegia
Disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction
Define optic atrophy
Death of the retinal ganglion cell axons that comprise the optic nerve
