Eye in Systemic Disease (neurological conditions) Flashcards
what are the main features of neuro-ophthalmic disease
eye movement defects- double vision
visual defects- visual acuity, field loss
what is the biggest cause of eye problems
microvascular disease
what is de-myelination
loss of myelin shealth from (optic) nerve making it inefficient
what are inter-nuclear ophthalmoplegia (INO)
lesion affects medial longitudinal fasciculus (MLF) (inter nuclear connections) resulting in cranial nerve 3 and 6 being unable to coordinate their signals
=when the patient’s gaze is directed away from the side of the lesion, the ipsilateral (adducting) eye will not adduct and the contralateral (abducting) eye demonstrates horizontal nystagmus
what are supra nuclear defects
when problem with occular motility arises from an area before the cranial nerves
what muscles are affected by a 6th nerve palsy
lateral rectus (inability to abduct eye)
what type of diplopia will someone with a 6th nerve palsy get
horizontal
what can cause a 6th nerve palsy
microvascular
raised ICP
tumour
congenital
why is the 6th cranial nerve susceptible to raised ICP
as comes up from bottom of brain stem over the petrous tip
what causes papilloedema
raised ICP
what nerve is affected by a fourth nerve palsy
superior oblique (in ability to look medially (intorsion) and down (deoression in adduction), with palsy eye will lift when look medially)
what nerve palsy do you get a head tilt in
trochlear (IV) nerve palsy as trying to lift head to match high eye
what are the actions of superior oblique muscle
intorsion (adduction)
depression in adduction
weak abduction
what can cause a IVth nerve palsy
congential decompensated (will have double vision)
microvascular
tumour
bilateral (closed head trauma)
what is a compensated nerve palsy
where brain is still able to fuse two fields of vision so wont have diplopia
what is the longest cranial nerve. why is this important
trochlear- 4th
comes out of posterior brain stem- susceptible to trauma
what muscles does the occulomotor nerve supply (III)
medial rectus inferior rectus superior rectus inferior oblique sphincter pupillae levator palpebrae superioris
what muscle palsy causes ptosis
levator palpaebrae superioris- CN III
what are the signs of a III nerve palsy
ocular position= down and out (lateral rectus and superior oblique only ones working)
droopy lid - ptosis
what can cause a III nerve palsy
microvascular tumour aneurysm (close to circle of willis) MS congenital
what can cause a PAINFUL third nerve palsy
aneurysm
what causes a PUPIL SPARING III nerve palsy
microvascular (as parasympathetics in III nerve on the outside- more likely to be affected by an aneurysm)
what are the key word causes of the three palsys
all caused by vasculopathic/ tumour
III= aneurysm IV= congenital/ trauma VI= cranial pressure
what can cause inter opthalmoplegia
MS, vascular, lots e.g. stroke
what is the hallmark of MS on an MRI
plaque in ventricles cause by demyelination
what are the parts of the optic pathway
optic nerve chiasm optic tracts lateral geniculate nucleus (splits and goes to different levels of the lobes- right goes to left etc) optic radiations cortex (occipital lobe)
what can cause visual field defects
vascular disease
space occupying lesion
demyelination
trauma (inc surgery)
why is there macular sparing in vision field loss caused by the visual cortex
as there is so many nerves within the macula
what are the pathologies of the optic nerve
ischaemic optic neuropathy
optic neuritis (MS)
tumours- meningioma, gliomas, haemangioma (vascular tumours)
will optic nerve defects present with horizontal or verticle defects
horizontal
will visual defects originating from the brain be horizontal or verticle
verticle
what are the features of optic neuritis
progressive visual loss (unilateral) pain behind eye (esp on movement) colour desaturation central scotoma (vision loss) gradual recovery over weeks- months
what is very specific to optic nerve damage
colour desaturation- will see differences in the colour red between eyes
what can follow optic neuritis
optic atrophy
what can affect the optic chiasm
pituitary tumour
craniopharyngioma
meningioma
what reflex is seen in a chiasm pathology
RAPD
what field defect will result from an optic chiasm pathology
bi-temporal
what happens to visual loss caused by pituitary tumours after the tumour is decompressed or removed
commonly reversed
how are pituitary tumours removed
via transsphenoidal surgery
what can affect the optic tract and radioatoins
tumours (primary and secondary)
demyelination
vascular anomalies
what visual defects arise from pathologies within the optic tracts and radiations
homonomous
macula not spared
quadrantanopia
incongrous
where do you know a pathology is if it is a quadrantanopia
after the lateral geniculate nucleus
why dont you get raised ICP in meningiomas
as grows very slowly
what pathologies can affect the occipital cortex
vascular disease (infarct) demyelination
what visual field defects do you get from pathologies in the occipital cortex
homonomous
macular sparing
congruous
what visual field defects are macular sparing
ones originating from the occipital cortex
what will cause lots of whits dots in a specific pattern that are all the same size in the eye
laser retinopathy treatment
what is the commonest cause of blindness in the western world
ARMD
what is the pathogenesis of diabetic retinopathy
chronic hyperglycaemia
= glycosylation of protein/ basement membrane
= loss of pericytes (cells on outer layer of capillaries)
= microaneurysm
= leakage/ ischaemia
what are the signs of non proliferative retinopathy
micro aneurysms/ dot and blot haemorrhages (red small dots)
hard exudates (yellow dots)
cotton wool patches (fluffy white patches of oedematous axons on the retina)
abnormal venous calibre (vessels not smooth)
intra-retinal microvascular abnormalities
what does ischaemia in the eye lead to
production of VEGF which causes neovascularisation- fragile vessels prone to haemorrhage
fibrotic scarring- shrink= retinal detachment
what is NVE and NVD
NVD= neovascularisation on optic nerve head
NVE= neovascularisation in the periphery of the retina
when does neovascularisation show that ischaemia is severe
if there are new vessels growing on the iris
also by the time you have NVD you have profound loss of useful vessels
how do you know where ischaemia is in eye
fine white vessels show closed arteries and venules- neovasularisation should stem from here
what is rubeosis iridis
when VEGF diffuses through vitreous into iris
very severe ischaemia in the eye
causes secondary glaucoma no sight restoration
neovascularisation in the iris
why do diabetic patients go blind
retinal oedema affecting the fovea
vitreous haemorrhage
scarring/ tractional retinal detachment
what are types of retinopathy
non proliferative (mild, moderate and severe) proliferative retinopathy
how do you classifymaculopathy
observable (vision hast deteriorated)
referable maculopathy
clinically significant maculopathy (oedema has spread to the centre of the fovea (foveal dip)
what happens to the foveal dip when oedema hits it
will pop up (like an umbrella inside out) and vision blurs
how do you manage diabetic retinopathy
optimise medical management of diabetes
laser- PPR (pan retinal photocoagulation), macular grid
surgery- vitrectomy
rehab- blind/ partially sighted
how does the laser work in diabetic retinopathy
kills bots of retina do reduce oxygen demand to rest of eye so centre can receive more nutrients and oxygen
are axons below or above the photoreceptors
above, light has to go through them to reach the photo receptors
why does the eye look pink
blood vessels in the choroid showing through
how do you treat disc neovascularisation
laser
how do you treat maculopathy
laser macula (less used now) or injections of VEGF antibodies
what shows the severity of hypertension in the eye
how the fundus looks and the retinal arteries
why do you people have hypertensive retinopathy
usually malignant hypertension
what does hypertensive retinopathy look like
like diabetic attenuated blood vessels (look like copper or silver wire) cotton wool spots hard exudates retinal haemorrhage optic disc oedema
what are the features of central retinal artery occulsion
cattle tracking in vessels
retinal oedema (pale)
foveal dip doesnt go white as axons over this so thin they dont go oedematous
sudden painless loss of vision (v profound)
retinal nerve fibre layer becomes swollen except the fovea (cherry red spot)
rarely recovers
why dont you get necrosis in macula in CRAO
as choroid supply very good here
what are the features of central retinal vein occlusion
no neovascularisation haemorrhages sudden painless visual loss range of visual loss haemorrhagic and exudative process downstream from occluded vein
why does the CRV occlude in diaebtes
Anulus- limited size hole for central artery and vein. When retina becomes bigger in hypertension it occludes this hole
what is used to image the capillary bed in CRVO
angiogram
what are the features of branch vein occlusion
painless disturbance in vision
may be assymptomatic
may be aware of loss of part of field
what are the features of sarcoidosis
uveitis- keratic precipitate
lung involvement
non caseating granulomas
what are the infective causes of uveitis
TB herpes zoster (and simplex) toxoplasmosis candidiasis syphillis lyme disease
what are the non infective causes of uveitis
idiopathic HLA-B27 juvenile arthritis (not it RA) sarcoidosis behcets disease
what is the histology of GCA
loss of lumen size, destruction of the lamina, multinucleated giant cell accumulation
what are the features of GCA
inflammation of middle sized arteries associated with polymyalgia rheumatica headache jaw claudication malaise raised PV blinding condition
what condition is GCA associated with
polymyalgia rheumatica
what are the features of thyroid eye disease
extra ocular:
- proptosis (due to muscle and fat swelling)
- lids: retraction, chemosis (conjunctival oedema), lag, pigmentation
- restrictive myopathy (diplopia)
ocular:
- anterior segment: chemosis, injection, exposure (cant close eye well), glaucoma
- posterior segment: choroidal folds, optic nerve swelling
what is the most common cause of unilateral and bilateral proptosis
thyroid eye disease
how do you treat thryoid eye disease
medical control- carbimazole, radioiodine, surgery
what are the eye features of SLE
ocular inflammation
what are the occular features of RA
dry eyes (keratoconjunctivitis sicca)
scleritis
corneal melt
(doesnt give yo intraocular inflammation- affects the surface of the eye)
what are the features of sjogrens syndrome
keratoconjunctivitis sicca xerostomia (dry mouth) dry featureless tongue RA infiltration of lacrimal glands
what are the features of marfans
Displacement of the lens (zonules) spontaneously rupture
Long fingers
high arched palate
tall
what way does the lens always dislocate in marfans
upwards(m for moon)
what dermatological features can affect the eyes
steven- johnson syndrome/ erythema multiforme drug or food hypersensitivity maulopapular rash stomatitis conjunctivitis
what are the features of stevens-johnsons syndrome
symblepharon ( partial or complete adhesion of the palpebral conjunctiva of the eyelid to the bulbar conjunctiva of the eyeball)
occlusion of lacrimal glands
corneal ulcers
what is the medial longitudinal fasiculus
in grey matter
links CN VIII to eye movement nerves (CN III, IV and VI)
what is the presentation of INO
inability to adduct (on side of lesion) and horizontal nystagmus on other eye
what cranial nerves are affected in internuclear ophthalmoplegia
CN III and VI (3 and 6)
remember its a horizontal nystagmus
