Clinical Pathology

Question 1

What is the only part of the body where there has never been a reported case of malignancy?

Answer 1

Epithelium of the lens

Question 2

What is the main pathology of the lens?

Answer 2

Cataracts

Question 3

What are cataracts?

Answer 3

Opacification within the lens = usually due to alteration in repair mechanism with age

Question 4

What happens as the epithelium of the lens matures?

Answer 4

Eventually the cell contents are replaced and the nucleus disappears = cell outline is left and becomes a fibre within the lens

Question 5

What happens to the fibres that occur in the lens over time?

Answer 5

Undergo a degenerative change causing opacifications = leads to cataracts

Question 6

What type of light increases the likelihood of developing cataracts?

Answer 6

Cumulative UVB damage

Question 7

What are some causes of cataracts?

Answer 7

Age, hypertension, smoking, post-operative trauma, metabolic disorders, genetics, diabetes

Question 8

How does diabetes influence cataract development?

Answer 8

Changes to osmotic pressures and altering of fluid in lens damages epithelial cells and fibres

Question 9

What is glaucoma?

Answer 9

Abnormal increase in intra-ocular pressure = biggest consequence to optic disc and nerve

Question 10

What is the pressure in the eyes related to?

Answer 10

Amount of vitreous fluid and anteriorly aqueous humour

Question 11

Where does the vitreous and aqueous humour drain out of the eye via?

Answer 11

The trabecular meshwork and the canal of Schlemm = blockage causes glaucoma

Question 12

What is the most common type of glaucoma?

Answer 12

Primary open angle glaucoma

Question 13

What are some features of open angle glaucoma?

Answer 13

Poor drainage through trabecular meshwork = slow onset, often asymptomatic, therapy aimed at slowing progression

Question 14

What causes closed angle glaucoma?

Answer 14

Drainage is patent but iris is opposed to the anterior eye = fluid can’t get passed it to drain

Question 15

What are some features of closed angle glaucoma?

Answer 15

Acute red eye and visual loss, headache with nausea and vomiting = treated by zapping a hole in the iris with a laser

Question 16

What occurs in cupping of the optic disc during glaucoma?

Answer 16

Damage to optic nerve/disc due to raised intra-ocular pressure = edges of disc become rolled up and centre becomes depressed

Question 17

What are some features of papilloedema?

Answer 17

Swelling of optic disc/nerve = related to raised intracranial pressure, visualised using ophthalmoscope

Question 18

What are some features of conjunctivitis?

Answer 18

Usually viral but may be bacterial or allergic = swelling, redness, heat, pain

Question 19

What is the difference between scleritis and episcleritis?

Answer 19

Scleritis is rarer and more severe than episcleritis

Question 20

What are some features of scleritis?

Answer 20

May be autoimmune (SLE, HLA-B27) = pain on movement of eye

Question 21

What are some features of episcleritis?

Answer 21

Superficial and self limiting, usually no clear cause

Question 22

What causes age related macular degeneration?

Answer 22

Due to underlying inflammatory process that occurs with age = accumulation of drusen (proteins, lipids, inflammatory mediators)

Question 23

What are some features of wet type age related macular degeneration?

Answer 23

Neovascularisation in choroid, mediated by VGEF, new vessels small and fragile so leak, more likely to cause visual loss

Question 24

How can wet type age related macular degeneration be treated?

Answer 24

With monoclonal antibodies to VGEF

Question 25

Is there significant vascular proliferation in dry type age related macular degeneration?

Answer 25

No

Question 26

How does diabetes affect the eye?

Answer 26

Hyperglycaemia changes osmotic pressures in the anterior part of the eye in front of the lens

Question 27

What ocular complaint may be the presenting feature of diabetes?

Answer 27

Blurred vision

Question 28

What are some pathologies caused by diabetes?

Answer 28

Argyll-Robertson pupils, peripheral neuropathy, cataracts, glaucoma, diabetic retinopathy

Question 29

How does diabetes cause cataracts?

Answer 29

Increased sugar content in lens, conversion of glucose to sorbitol, altered osmotic gradients cause swelling and fibre disruption

Question 30

What type of glaucoma is caused by diabetes?

Answer 30

Rubeotic glaucoma = new vessel formation obstructs angle

Question 31

What are some features of diabetic retinopathy?

Answer 31

Poor vessel function, leaky vessels, small aneurysms, new vessel formation if severe, oedema, vision loss (worse if macula affected)

Question 32

What are some tumours that may occur in the eye?

Answer 32

Basal cell carcinoma, squamous cell carcinoma, melanoma

Question 33

What may cause an arterial occlusion in the eye?

Answer 33

Carotid/thromboembolic disease