Pathogenesis Of Inflammatory Eye Disease

Question 1

What is inflammation?

Answer 1

The response of living tissue to damaging stimuli, direct immune comments to site of damage and contain damage and initiate repair

Question 2

Name six causes of inflammation

Answer 2

1) Infection
2) Hypersensitivity reactions
3) Autoimmunity
4) Trauma
5) Chemical/toxic
6) Radiation

Question 3

What are five signs of inflammation

Answer 3

1) Redness
2) Pain
3) Warmth
4) Swelling
5) Loss of function

Question 4

What is the mechanism of acute inflammation?

Answer 4

Vascular events (vasodilation, increased blood flow, increased permeability—> leads to oedema, movement of inflammatory cells from BV to site of injury)
cellular events (involved in initiation and propagation) —> Leukocytes move into tissue, under influence of inflammatory mediators marination occurs, rolling into vessel wall = DIAPEDESIS

Question 5

What triggers acute inflammation?

Answer 5

Inflammatory mediators which are involved in the initiation and prorogation

Question 6

What are four major features of an inflammatory response and how do they correspond to the signs of inflammation?

Answer 6

• Vasodilation = redness
• Increased blood flow= heat
• Increased vascular permeability = swelling/oedema
• Movement of inflammatory cells to site of injury –> minimise damage

Question 7

What are the first cells to migrate to site of injury in an acute inflammatory response?

Answer 7

Neutrophils

Question 8

What is margination?

Answer 8

Under the influence of inflammatory mediators, the inflammatory cell moves from the center of the blood column to the endothelial wall of the blood vessel

Question 9

How does an inflammatory cell stick on to the blood cell wall?

Answer 9

By adhesion molecules which are expressed by the endothelium

Question 10

What is the process which describes the inflammatory cells squeezing through the vessel wall?

Answer 10

Diapedesis

Question 11

Name the three process which describes an inflammatory cell exiting a blood vessel.

Answer 11

Margination, rolling and diapedesis

Question 12

What is chemotaxis?

Answer 12

Once a inflammatory cell leaves a BV, it moves along concentration gradients and inflammation chemicals

Question 13

What is the role of a phagocyte and how is this achieved?

Answer 13

Eliminate pathogens or damages tissues which is done by them attaching to microorganisms via surface receptors, after the binding, it is phagocytsed and destroyed = PHAGOCYTOSIS

Question 14

What enhances phagocytosis?

Answer 14

Antibodies and the complement system of proteins= OPSONIZATION

Question 15

What is an opsonin?

Answer 15

An antibody which binds to foreign organisms to make them more susceptible to phagocytosis

Question 16

What primarily controls the vascular and cellular events?

Answer 16

Chemical mediators which are produced from inflammatory cells

Question 17

What cells produce vasoactive amines (e.g histamine serotonin)?

Answer 17

Mast cells and basophils

Question 18

What is an example of a vasoactive amine?

Answer 18

Histamine serotonin

Question 19

Name four inflammatory mediators and give examples of them.

Answer 19

1) Vasoactive amines –> histamine serotonin
2) Plasma protease –> complement, kinins
3) Arachidonic acid metabolites (eicosanoids)
4) Cytokines –> produced by lymphocytes

Question 20

Explain the process of eicosanoid synthesis

Answer 20

1) Phosoplipids are converted into arachidonic acid
2) Arachidonic acid is then converted into a variety of inflammatory mediators
3) One example is the enzyme lipoxygenase converts AA to leukotrienes
4) Another example is the enzymes cyclo-oxygenase converts AA to prostaglandins, throboxane which is involved in initiation and propagation

Question 21

Where are mast cells found in the eye and what type of inflammation cause is it involved in?

Answer 21

The conjunctiva and involved in hypersensitivity reactions

Question 22

What do mast cells contain?

Answer 22

Granules containing pre formed mediators such as histamine and heparin and neutral protease

Question 23

What does a release of mediators cause?

Answer 23

Vasodilation and increased vascular permeability

Question 24

What are the three possible outcomes of acute inflammation?

Answer 24

• Complete resolution
• Scar formation (depends on how much scare tissue is formed)
• Progress to chronic inflammation

Question 25

Injection is a sign of what?

Answer 25

Vasodilation

Question 26

What are ocular responses to inflammation?

Answer 26

• Redness
• Oedema
• Exudates (KPs)
• Cellular infiltration ( acute=neutrophils, chronic= macrophages and lymphocytes)
• Discharge (serous, mucopurulent and purulent)
• Conjunctival papillae and follicles
• Inflammation of the posterior segment

Question 27

What is flare caused by?

Answer 27

Protein entering the aqueous humor due to a breakdown of the blood aqueous barrier- has a cloudy appearance

Question 28

What are KPs?

Answer 28

Inflammatory cells leaving the vascular system and circulate the aqueous humor to then be deposited in a clump on corneal endothelium

Question 29

What eye disease is papillae common in?

Answer 29

Allergic eye disease

Question 30

What eye conditions can inflammation of the posterior segment indicate?

Answer 30

Anterior ischaemic optic neuropathy and sarcodosis

Question 31

What is an ocular autoimmune disease?

Answer 31

Uveitis

Question 32

What is sympathetic ophthalmia?

Answer 32

It is followed after a penetrating injury that effects both eyes within three weeks to a year.

Question 33

What mechanisms lead to cell and tissue damage in autoimmune disease?

Answer 33

1) Autoreactive T-helper cells initiate cell damage due to the production of cytokines
2) Autoreactive cytotoxic T cells also cause tissue damage
3) Autoanitbodies cause tissue by type II mechanism

Question 34

What is a t-helper cell?

Answer 34

They sense infection they activate other immune cells to fight

Question 35

do you know the types of hypersensitivity reactions 1-4?

Answer 35

No- then go through it

Question 36

What two types of hypersensitivity reactions cause allergic eye disease?

Answer 36

Type I and Type IV

Question 37

What is another word for Type 1 hypersensitivity reaction and what is it caused by?

Answer 37

Mast cell mediated hypersensitivity reaction and is caused by overproduction of IgE