Clinical pathology Flashcards
What is cataracts?
Opacification of the lens
What is the commonest cause of cataracts?
Age degeneration due to UVB damage
What are other causes besides age that can cause cataracts?
Hypertension Smoking Post op and trauma Metabolic disorder Genetic T1 and T2DM
What is glaucoma?
Abnormal increase in pressure in the eye
What determines the pressure in the eye?
Amount of vitreous fluid and anteriorly aqueous humour
Produced in the ciliary body and exits through the canal of schlemm at the iridocorneal angle through trabecular meshwork
What will glaucoma do to the optic nerve and disc?
Damage - will cause optic atrophy (white optic disc)
What is primary open glaucoma?
Poor drainage through the trabecular meshwork or canal of schlemm
What is angle closure glaucoma?
Iris is opposed to the anterior eye and therefore aqueous humour stuck in the posterior segment of the anterior chamber of the eye
Compare open and closed glaucoma?
Open is a slow onset - often asymptomatic and now screened for
Closed angle is an emergency
What will closed angle glaucoma present with?
Acute red eye
Visual loss
Headache with nausea and vomiting
What is the treatment for open glaucoma?
Pharmacological therapy to slow down the widening of the canal
What is the treatment for closed angle glaucoma?
Create a hole in the iris with a laser
What is cupping?
Raised intraocular pressure damages the optic disc and nerve and so the edges of the disc become rolled up and the centre becomes depressed
What is papilloedema?
Swelling of the optic nerve/ disc
Non-specific finding related to increased ICP
What is conjunctivitis?
Inflammation of conjunctiva
Swelling, redness, pain and heat
Usually viral but can be bacterial or allergic
What conditions are associated with scleritis?
SLE
HLA-B27 - ankylosing spondylitis
What can be seen on fundoscopy of macular degeneration?
Drusen - proteins, lipids and inflammatory mediators
What is the difference between dry and wet ARMD?
Dry - no vascular proliferation
Wet - neovascularization in choroid mediated by VEGF. More likely to result in visual loss
How can wet ARMD be treated?
Anti-VEGF intraocular injections
What effect does hyperglycemia have on the eye?
Changes osmotic pressures in the anterior chamber of the eye and in front of the lens
What is an argyll robertson pupil?
Pupil accommodates but doesn’t react to light
How can diabetes mellitus cause cataracts?
Increased sugar content in the lens causes conversion of glucose to sorbitol - altered osmotic gradient leading to swelling and fibre disruption
What is rubeotic glaucoma?
New vessel formation on iris causes an obstructing angle
What will diabetic retinopathy show on examination?
Dot and blot haemorrhages
Hard exudates
New vessel formation
Microaneurysms
What vascular issues can occur with the eye?
Central retinal artery occlusion
Central retinal vein occlusion
