Clinical Pathology Flashcards
what is cataracts?
blurring of the lens
maincauses of cataracts?
sun damage diabetes genetic hypertension smoking post-op and trauma metabolic disorders
what is glaucoma?
abnormal increase in pressure in the eye
- related to the amount of vitreous fluid and anteriorly aqueous humour
where does the aqueous fluid usually drain?
trabecular meshwork/canal of schlemm into scleral venous sinus
blockage of this can cause increased pressure and lead to glaucoma
what is the consequence of increased pressure in the eye?
mainly causes problems at the back of the eye (optic nerve etc)
structures at the front can be compressed
what is the most common type of glaucoma?
primary open angled glaucoma
drainage of aqueous humour is blocked
secretion of aqueous humour is clear
what is angle closure glaucoma?
where drainage through the meshwork is patent
iris is essentially opposed to anterior eye and fluid cant get passed to the meshwork
(iridocorneal angle?)
open glaucoma?
slow onset
often asymptomatic and now screened for
many people don’t know they have it
pharmacological therapy aimed at slowing it down by widening canal etc
closed glaucoma?
1/3 are a medical emergency
can lose sight v quickly
how does closed glaucoma present?
acute red eye
visual loss
headache nausea and vomiting
how is closed glaucoma managed?
zap a hole in iris with a laser
what is cupping?
raised intraocular pressure which damages the optic disc and nerve
essentially the edges of the disc become rolled up and the centre becomes depressed
sign of raised intraocular pressure
what is papilloedema?
swelling of the optic nerve/disc
non-specific finding related to raised intracranial pressure
what is conjunctivitis?
inflammation of the conjunctiva
how does conjunctivitis present?
swelling
redness
pain
heat
causes of conjunctivitis?
usually viral
occasionally bacterial
sometimes allergic
what is scleritis?
inflammation of sclera
how does scleritis rpesent?
pain onmovement
what underlying pathology can be associated with scleritis?
can have an underlying autoimmune aetiology
- SLE
- HLA B27
what is episcleritis?
superficial inflammation of sclera
less severe than scleritis
self limiting
causes of episcleritis?
usually no real cause
what is ARMD and what 2 types exist?
ARMD = age related macular degeneration dry = no vascular proliferation wet = vascular proliferation (worse than dry)
what causes ARMD?
unclear
age-related and underlying inflammatory process
accumulation of by-products (drusen)
what is drusen?
proteins and lipids and inflammatory mediatory
by-product of inflammatory process
present in macular degeneration
shows as yellow bits in retina
what causes wet ARMD?
neovascularisation in choroid
new vessels are small and fragile and therefore leaky
more lkely to result in visual loss
how is wet ARMD managed?
monoclonal antibodies to VEGF
what mediated wet ARMD?
VEGF
how can diabetes affect the eye?
cataract
hyperglycaemia (changes osmotic pressure in anterior chamber)
blurred vision (often presenting complaint in T1DM)
pupils - Argyll Robertson pupil, peripheral neuropathy
what is Argyll Robertson pupil?
accommodation reflex intact
light reflex not intact
how does diabetes cause cataracts?
increased sugar content in lens
conversion of glucose to sorbitol
altered gradients - swelling and fibre disruption
scarring
what is diabetic glaucoma known as?
rubeotic glaucoma
how does diabetes cause glaucoma?
new vessel formation obstructing angle
how does diabetic retinopathy occur?
complex mechanisms leading to poor function of vessels
leaky vessels and small aneurysms forming
if severe - new vessel formation
oedema
if macula affected, visual loss is worse
name 2 vascular diseases of the eye
central retinal artery occlusion (CRAO)
central retinal vein occlusion (CRVO)
causes of CRAO?
thromboembolic disease (often originating in carotids) same pathogenesis as arterial occlusion anywhere else in the body
causes of CRVO?
thrombosis
vasculitis
what vasculitis is most likely to affect the eye?
giant cell
what cutaneous cancers can occur in the eye?
BCC
SCC
melanoma
retinal melanoma
