Clinical Pathology Flashcards
What is the only part of the body where there has never been a reported case of malignancy?
Epithelium of the lens
What is the main pathology of the lens?
Cataracts
What are cataracts?
Opacification within the lens = usually due to alteration in repair mechanism with age
What happens as the epithelium of the lens matures?
Eventually the cell contents are replaced and the nucleus disappears = cell outline is left and becomes a fibre within the lens
What happens to the fibres that occur in the lens over time?
Undergo a degenerative change causing opacifications = leads to cataracts
What type of light increases the likelihood of developing cataracts?
Cumulative UVB damage
What are some causes of cataracts?
Age, hypertension, smoking, post-operative trauma, metabolic disorders, genetics, diabetes
How does diabetes influence cataract development?
Changes to osmotic pressures and altering of fluid in lens damages epithelial cells and fibres
What is glaucoma?
Abnormal increase in intra-ocular pressure = biggest consequence to optic disc and nerve
What is the pressure in the eyes related to?
Amount of vitreous fluid and anteriorly aqueous humour
Where does the vitreous and aqueous humour drain out of the eye via?
The trabecular meshwork and the canal of Schlemm = blockage causes glaucoma
What is the most common type of glaucoma?
Primary open angle glaucoma
What are some features of open angle glaucoma?
Poor drainage through trabecular meshwork = slow onset, often asymptomatic, therapy aimed at slowing progression
What causes closed angle glaucoma?
Drainage is patent but iris is opposed to the anterior eye = fluid can’t get passed it to drain
What are some features of closed angle glaucoma?
Acute red eye and visual loss, headache with nausea and vomiting = treated by zapping a hole in the iris with a laser
What occurs in cupping of the optic disc during glaucoma?
Damage to optic nerve/disc due to raised intra-ocular pressure = edges of disc become rolled up and centre becomes depressed
What are some features of papilloedema?
Swelling of optic disc/nerve = related to raised intracranial pressure, visualised using ophthalmoscope
What are some features of conjunctivitis?
Usually viral but may be bacterial or allergic = swelling, redness, heat, pain
What is the difference between scleritis and episcleritis?
Scleritis is rarer and more severe than episcleritis
What are some features of scleritis?
May be autoimmune (SLE, HLA-B27) = pain on movement of eye
What are some features of episcleritis?
Superficial and self limiting, usually no clear cause
What causes age related macular degeneration?
Due to underlying inflammatory process that occurs with age = accumulation of drusen (proteins, lipids, inflammatory mediators)
What are some features of wet type age related macular degeneration?
Neovascularisation in choroid, mediated by VGEF, new vessels small and fragile so leak, more likely to cause visual loss
How can wet type age related macular degeneration be treated?
With monoclonal antibodies to VGEF
Is there significant vascular proliferation in dry type age related macular degeneration?
No
How does diabetes affect the eye?
Hyperglycaemia changes osmotic pressures in the anterior part of the eye in front of the lens
What ocular complaint may be the presenting feature of diabetes?
Blurred vision
What are some pathologies caused by diabetes?
Argyll-Robertson pupils, peripheral neuropathy, cataracts, glaucoma, diabetic retinopathy
How does diabetes cause cataracts?
Increased sugar content in lens, conversion of glucose to sorbitol, altered osmotic gradients cause swelling and fibre disruption
What type of glaucoma is caused by diabetes?
Rubeotic glaucoma = new vessel formation obstructs angle
What are some features of diabetic retinopathy?
Poor vessel function, leaky vessels, small aneurysms, new vessel formation if severe, oedema, vision loss (worse if macula affected)
What are some tumours that may occur in the eye?
Basal cell carcinoma, squamous cell carcinoma, melanoma
What may cause an arterial occlusion in the eye?
Carotid/thromboembolic disease
