Retinal Vein Occlusion/Retinal artery occlusion/retinitis pigmentosa Flashcards
How does retinal vein occlusion occur?
Occurs when a blood clot (thrombus) forms in the retinal veins and blocks the drainage of blood from the retina.
The central retinal vein runs through the optic nerve and is responsible for draining blood from the retina.
There are four retinal veins that make up the central retinal vein (when the central retinal vein is blocked it causes problems in the whole retina) what is the pathophysiology when one of the veins are blocked?
Blockage of a retinal vein causes pooling of blood in the retina, this results in leakage of fluid and blood causing macular oedema and retinal haemorrhages.
This results in damage to the tissue in the retina and loss of vision
It also leads to the release of VEGF, which stimulates the development of new blood vessels- neovascularisation
What is the presentation of central retinal vein occlusion?
Blockage of one of the retinal veins causes sudden painless loss of vision.
What are the risk factors for retinal vein occlusion?
Similae to those of MI Hypertension High cholesterol Diabetes Smoking Glaucoma SLE
What can be used to diagnose retinal vein occlusion and what would you see?
. Fundoscopy
. Flame and blot haemorrhages
. Optic disc oedema
. Macula oedema
Other than doing fundoscopy, what other tests would you consider in a patient with retinal vein occlusion?
FBC for leukaemia
ESR for inflammatory disorders
Blood pressure for hypertension
Serum glucose for diabetes
What is the management of retinal vein occlusion?
Should be referred immediately to an opthalmologist for assesment and management
The aim of the treatment is to treat macular oedema and prevent neovascularisation
The options are…
- laser photocoagulation
- intravitreal steroids ie: dexamethasone
- anti VEGF therapies
Give an example of an anti VEGF med…
Ranibizumab
What is the centrak retinal arteyr occlusion?
This is where something blocks the flow of blood through the central retinal artery, the central retinal artery supplies the blood to the retina which is a branch of the ophthalmic artery which is a branch of the internal carotid artery.
What are the risk factors for central retinal artery occlusion?
Older age Family history Smoking Alcohol consumption Hypertension Diabetes Poor diet Inactivity Obesity
What is the presentation of central retinal artery occlusion?
Sudden painless loss of vision
There will also be a relative afferent pupillary defect (where the pupil in the affected eye constricts more than the other eye.
It occurs because the input is not being sensed by the ischaemic retina when testing the direct light reflex but is being sensed by the normal retina during the consensual light reflex.
What will fundoscopy show for someone with central retinal artery occlusion?
Pale retina with a cherry red spot
The retina is pale due to the lack of perfusion with blood, the cherry red spot is the macula which shows the choroid below.
What should older patients be tested for and ultimately treated for if they have suspected central retinal artery occlusion?
Giant cell arteritis
This is an important potentially reversible cause
Testing involves ESR and temporal artery biopsy
How is Giant cell arteritis treated if suspected?
High dose steroids- prednisolone 60mg
What is the management of central retinal artery occlusion?
Ocular massage
Removing fluid from the anterior chamber to reduce intraocular pressure
Inhaling carbogen (a mixture of 5% CO2 and 95% oxygen) to dilate the artery
Sublingual isosorbide dinitrate to dilate the artery
Long term involves treating reversible risk factors and secondary prevention of cardiovascular disease.
What is retinitis pigmentosa?
This is a congenital inherited condition where there is degeneration of rods and cones in the retina. There are many different causes and some are systsemic whilst others are isolated cases of retinitis pigmentosa.
Do rods or cones degenerate more in genetic causes of retinitis pigmentosa?
In most genetic causes, the rods degenerate more than the cones which leads to night blindness
They get decreased central and peripheral vision.
What is the presentation of retinitis pigmentosa?
Night blindness is often the first symptom
Peripheral vision is lost before the central vision
What will fundoscopy show if someone has retinitis pigmentosa?
Pigmentation, this is described as ‘bone spicule’ pigmentation
There may be associated narrowing of the arterioles and a waxy or pale appearance to the optic disc
Give one example of an associated systemic disease of retinitis pigementosa and what it leads to…
Ushers syndrome- this causes hearing loss + retinitis pigmentosa
What is the management of retinitis pigmentosa?
Referral to an opthalmologist for assesment and diagnosis
Genetic counselling
Vision aids
Sunglasses to protect the retina from accelerated damage
Driving limitations and informing the DVLA
Regular follow up to assess vision and check for any reversible conditions that may worsen the vision ie: cataracts
Some options that may be considered to slow the disease process... Vitamin and antioxidant supplements Oral acetazolamide Topical dorzolamide Steroid injections Anti VEGF
Gene therapy in the future
