The eye in systemic disease (incomplete) Flashcards
Where is the visual cortex found?
Occipital lobe
What are the two most important clinical features which suggest neuro-ophthalmic disease?
Eye movement defects
Visual defects
What symptom might a patient with eye movement defects describe?
Double vision
What are the causes of neuro-ophthalmic disease?
Vascular disease Space occupying lesions Trauma Demyelination Inflammation/infection Congenital
What is the most common cause of neuro-ophthalmic disease?
Vascular
How is suspected neuro-ophthalmic disease investigated?
Examination (ophtha + neuro)
Blood tests
MRI
What memory aid can be used to remember the cranial nerves supplying the eye?
LR6 (lateral rectus VI)
SO4 (superior oblique IV)
AO3 (all others III)
What does supra-nuclear refer to with respect to the brain?
Within the brain lobes (e.g supra-nuclear pathology)
What does intra-nuclear refer to with respect to the brain)
Between nerve nuclei
Which muscles control intorsion and extorsion?
Inferior and superior oblique
What muscle(s) is paralysed in a sixth nerve palsy?
Lateral rectus
What type of squint does a patient with sixth nerve palsy have? Why?
Esotropic (convergent)
The lateral rectus muscle is cannot perform abduction
What are the causes of sixth nerve palsy?
Microvascular (hypertension, diabetes)
Raised ICP
Tumour
Congenital
Microvascular causes of sixth nerve palsy usually resolve within a couple of months. T/F
True
How will sixth nerve palsy due to raised ICP present?
Sudden onset eye movement defect/double vision
Headache
Why does raised ICP cause compression of the sixth cranial nerve?
It runs over the petrous part of the temporal bone
Is papilloedema associated with sixth nerve palsy bilateral?
Yep
What is the most common cause of sixth nerve palsy?
Microvascular (2nd is raised ICP)
Which muscle(s) is paralysed in fourth cranial nerve palsy?
Superior oblique
Which movements does the superior oblique carry out?
Intorsion
Depression in adduction
Abduction (weak)
Which direction will an eye be looking with fourth nerve palsy?
Up and out
What sign will a patient with fourth nerve palsy characteristically have? Why?
Tilted head
Compensates for weak intorsion
What are the clinical signs of bilateral fourth nerve palsy?
Chin depressed
What is the cause of bilateral fourth nerve palsy? Why?
Head trauma (closed) Long intracranial course and thin easily stretched nerve
What are the causes of fourth nerve palsy? Which is most common?
Congenital (common)
Microvascular
Tumour
Head trauma
Which is the least common cranial nerve palsy with reference to the nerves supplying eye movments?
Oculomotor (III) nerve palsy
How does an eye with III nerve palsy appear?
Down and out
Ptosis
Mydriasis
Which muscles are affected in III nerve palsy?
Inferior oblique Medial rectus Superior rectus Inferior rectus Sphincter pupillae Levator palpebrae superioris
What are the causes of III nerve palsy?
Microvascular Tumour Aneurysm Multiple sclerosis Congenital
What will be the cause of a painful III nerve palsy?
Aneurysm
Do microvascular causes of III nerve palsy cause mydriasis? Do aneurysms?
Nah
Always
What is inter-nuclear opthalmoplegia?
Impaired horizontal eye movement (weak adduction of affected eye and abduction nystagmus of unaffected eye)
What is the most common cause of inter-nuclear opthalmoplegia?
Multiple sclerosis
2nd is vascular
Working inter-nuclear pathways ensure that both eyes work in synchrony. T/F
True!
Inter-nuclear opthalmoplegia arises from problems within which part of the brainstem?
Medial longitudinal fasciculus
What is demyelination?
Damage to myelin insulator sheath surrounding nerves (known as white matter change)
Describe the optic pathway
Optic nerve --> Optic chiasm --> Optic tract --> Optic radiation --> Visual cortex
What are the causes of pathology within the optic pathway?
Vascular (cerebrovascular accident)
Space occupying lesion
Demyelination (multiple sclerosis)
Trauma (surgical)
Pathology with the left optic nerve will result in which visual field defect?
Complete loss of vision in left eye
Horizontal superior OR inferior loss of vision in left eye
Pathology affecting the optic chiasm will result in which visual field defect?
Bitemporal hemianopsia
Pathology affecting the left optic tract will result in which visual field defect?
Right sided hemianopsia
Pathology affecting the occipital cortex will result in which visual field defect?
Homogenous hemianopsia
Pathology affecting one of the optic radiations will result in which visual field defect?
Quadranopsia
List pathologies which affect the optic nerve?
Ischaemic optic neuropathy
Optic neuritis
Tumours
What is the most common cause of optic neuritis?
Multiple sclerosis
What is optic neuritis?
Inflammation of the optic nerve
List three tumours that can affect the optic nerve
Meningioma
Glioma
Haemangioma
How does optic neuritis present?
Progressive visual loss Unilateral Pain behind eye exacerbated by movement Colour desaturation Central scotoma
How is optic neuritis managed?
Self resolving over weeks/months
What might be seen on fundoscopy following optic neuritis?
Optic atrophy (pale, featureless disc)
Haemangioma can cause which ocular symptoms? What is the most common cause?
Unilateral proptosis
Optic nerve compression (+ decreased vision)
Extraocular muscle restriction (+ eye movement defect –> diplopia)
Congenital
Which pathologies affect the optic chiasm? Which of these affect children?
Pituitary tumour
Craniopharyngioma (children)
Meningioma
How are visual defects caused by pituitary tumours managed?
Removal of tumour usually restores vision
Which pathologies affect the optic tracts + radiations?
Tumours
Demyelination (multiple sclerosis)
Vascular abnormalities (AV malformation)
With regards to defects within the optic tracts/radiations, is the macula spared?
Nope
Can optic tract/radiation pathologies cause incongruous defects?
Yes!
Which pathologies affect the occipital cortex?
Vascular disease (cerebrovascular accident) Demyelination (multiple sclerosis)
Do pathologies affecting the occipital cortex result in macular sparing?
Yes!
Can occipital cortex pathologies cause incongruous defects?
No - tend to be congruous
A ring enhancing lesion on MRI tends to be characteristic of what?
Abscess (TB, parasites, chronic bacterial infection)
Over which age is vascular disease the most common aetiology (in general) for neuro-opthalmic disease?
> 50
