Acute Vitreoretinal Pathologies Flashcards
what is this and where in the retina does it take place
pre retinal haemorrhage
in the sub hyaloid space
between the post hyaloid and internal limiting membrane
what are the 2 causes of a vitreous haemorrhage
Damage to normal blood vessels
or
Growth of abnormal blood vessels
how does damage to normal blood vessels cause a vitreous haemorrhage and name 2 examples
Retinal blood vessels that are damaged through injury or trauma can cause a vitreous haemorrhage.
Posterior vitreous detachment
Retinal tears
how does growth of abnormal blood vessels cause a vitreous haemorrhage and name 5 examples
Abnormal retinal blood vessels are typically the result of neovascularization due to ischemia in diseases such as:
diabetic retinopathy sickle cell retinopathy retinal vein occlusion retinopathy of prematurity ocular ischemic syndrome
what is this a sign of
which type of px is it more commonly found in
what type of symptoms will the px experience
and where in the retina is this found
Retinal macroaneursym
more common in elderly hypertensive women
haemorrhaging of the arteriole macroaneurysm presents acutely with rapid visual deterioration
multi layered involving the - vitreous, pre retinal, intra retinal and sub retinal spaces
describe how a Rhegmatogenous retinal detachment takes place
This results when a hole, tear, or break in the neuronal layer allows fluid from the vitreous to seep between and separate sensory and RPE layers
describe how a Traction retinal detachment takes place
This results from adhesions between the vitreous gel/fibrovascular proliferation and the retina
describe how a Exudative (serous) retinal detachment takes place
This results from exudation of material into the subretinal space from retinal vessels – ocular tumour
which type of retinal detachment is not present with a vitreous haemorrhage
Exudative (serous) retinal detachment
how does a gas bubble procedure to treat a retinal detachment work
when is it not suitable to do this tx
what is expected of this px after the procedure
The gas bubble keeps the retinal tear dry while the healing takes place . The gas disappears after a few weeks
cannot to is a px is going to travel in air due to air pressure
px is expected to lie face down for a 5-8 days, so the gas bubble floats up and keeps the retina dry
explain how scleral buckling works as a treatment for a retinal detachment
the explant or buckle pushes the outside layers of the eye against the retinal tear to allow it to heal, and to stop the flow of fluid behind the retina
any remaining fluid is then absorbed by the outer layers of the retina
explain how a vitrectomy is carried out
A vitrectomy instrument is used to drain fluid that is behind the retina
a fibre optic light is used to aid this
in order to keep a steady IOP, fluid goes into the eye through a cannula to replace the vitreous that is removed
Name this condition
acute retinal necrosis ARN
with Acute Retinal Necrosis
In 1994, the Executive Committee of the American Uveitis Society refined the definition of ARN based on clinical characteristics and disease course to include what 5 signs
1) one or more foci of retinal necrosis with discrete borders located in the peripheral retina;
2) rapid progression in the absence of antiviral therapy;
3) circumferential spread;
4) evidence of occlusive vasculopathy with arterial involvement
5) a prominent inflammatory reaction in the vitreous and anterior chambers
what are the anterior 4 signs and 2 symptoms of someone with Acute Retinal Necrosis
photophobia and pain
anterior chamber inflammation
secondary KPs
episcleritis and scleritis
corneal oedema
what are the 4 posterior signs and 2 symptoms of someone with Acute Retinal Necrosis
flashes and floaters
vitritis - hazy appearance
vascular/arterialitis - haemorrhages
peripheral retinitis - white patches
swelling of the optic disc
how is acute retinal necrosis ARN treated
anti virals
given intravenously, orally or intravitreally e.g. aciclover, ganciclover
after the antivirals - given steroids to dampen down the inflammation
what is this condition
porn - progressive outer retinal necrosis
what is the difference between porn - progressive outer retinal necrosis and ARN - acute retinal necrosis
with porn - there is no haziness, you get a clear view of the retina because the inflammatory response is not to the same degree as ARM
which type of people does porn affect
people with compromised immune systems e.g. AIDS
what are the clinical signs of porn - progressive outer retinal necrosis and how is it treated
what risk is there with someone who has porn
areas of: haemorrhages white areas of retinitis and sheathing of the retinal vasculature
Tx = antiviral agents given intravitrially
Risk of - retial detachment
what is this condition called
what 2 characteristics do you see and why do these occur
Neuroretinitis
optic nerve oedema
and
macula star/stellate maculopathy
because of inflammation due to increased permeability of the optic disc vasculature which causes a secondary macula star
this can be from infective causes of vasculitis
what 2 parts of the retina are inflamed with Neuroretinitis
optic nerve
and
neuroretina
what causes the characteristics of Neuroretinitis
optic disc swelling
list 7 infective causes of Neuroretinitis
bartinella cat scratch disease syphilis tuberculosis lyme disease leptospirosis toxoplasmosis
what organism is in cat scratch disease which can cause neuroretinitis and how does this get transmitted
Bartonella hensela
transmitted from a flea to the cat and then to the human host