Pathology: Acute Inflammation

Question 1

List the disease types described by acronym VINDICATE

Answer 1

V - Vascular
I - Inflammation
N - Neoplasia
D - Drugs/toxins
I - Iatrogenic
C - Congenital
A - Autoimmune
T - Trauma
E - Endocrine

Question 2

What are the 2 main phases of acute inflammation?

Answer 2

Vascular phase

Cellular phase

Question 3

Outline the vascular phase of acute inflammation

Answer 3

Vasodilation
-->
Stasis (blood slows, loss of laminar flow)
-->
White cell margination
-->
Rolling & Adhesion molecules
-->
Vascular permeability increases
-->
Diapedesis and transcytosis

Question 4

Outline the cellular phase of acute inflammation

Answer 4

Chemotaxis
-->
Opsonization
--> 
Phagocytosis & other "on-site immune functions"

Question 5

Describe the vasodilation that is part of the vascular phase of acute inflammation

Answer 5

• Firstly arterioles vasodilate, then capillaries do
• Mediated by histamine and nitric oxide (NO)
• Results in increased calor and rubor
• Causes a decrease in blood rate of flow

Question 6

Describe the stasis involved in the vascular phase of acute inflammation

Answer 6

• Normally blood flows centrally in the vessel
• Vasodilation causes a decreased rate of flow
• Allows cells white cell margination

Question 7

Describe white cell margination

Answer 7

Due to a decreased blood flow rate in vessels

Larger cells (like white cells) move to the periphery of the vessels

Question 8

Describe rolling and the expression of cell adhesion molecules

Answer 8

• Endothelial cells express Intracellular Adhesion Molecule (ICAM), Vascular adhesion molecule (VCAM) and selectins on their luminal surface
• They express them do to chemical signals
• These weakly bind to integrins and glycoproteins
• The bonds rapidly break and reform causing the leukocytes to roll along the vessel wall

Question 9

Describe how leukocytes stop rolling and come to a halt

Answer 9

• Chemokines from the site of injury bind to prostaglandins on the endothelial cell surface
• These increase the affinity of VCAM and ICAM for integrins
• This binding with increased affinity halts the cell

Question 10

What factors increase selectin expression?

What factors increase ICAM and VCAM expression?

Answer 10

Histamine and Thrombin increase selectin expression

Tumour necrosis factor (TNF) and Interleukin-1 (IL-1) increase VCAM and ICAM expression

Question 11

Are selectin, ICAM, VCAM, integrin and glycoproteins on the endothelial cell or leukocyte?

Answer 11

Endothelial cell:
ICAM, VCAM, selectins

Leukocyte:
Integrin, glycoproteins

Question 12

Describe the factors that can increase vascular permeability (“leakyness”)

Answer 12

Endothelial contraction - due chemical signals (histamine, bradykinin, substance P, leukotrienes)

Direct injury - burns, toxins

Leukocytes - self damage

Transcytosis - substances transported (via vesicles) through cells (due to VEGF)

New vessel formation - due to vascular endothelial growth factor (VEGF)

Question 13

What is the clinical consequence of increased vascular permeability

Answer 13

Oedema

As fluid escapes the vessel

Question 14

What is the role of vascular endothelial growth factor in increasing vascular permeability?

Answer 14

VEGF mediates transcytosis

Mediates new vessel formation

Question 15

Describe how leukocytes migrate out of the vessels

Answer 15

By diapedesis

• Leukocyte extends pseudopods through gaps between endothelial cells
• Pulls itself through the epithelium into the intravascular space

Question 16

Describe how the leukocyte travels to the site of injury

Answer 16

By chemotaxis

• Follows a chemical gradient
• The chemicals used are compliment (C5a), leukotrienes, cytokines, and bacterial components

Question 17

List some of the functions of leukocytes when the arrive at the site of injury?

Answer 17

• Releasing cytokines

- Phagocytosis

Question 18

What are the 4 clinical features of inflammation?

Answer 18

Rubor - Redness

Calor - Heat

Tumour - Swelling

Dolor - Pain

Question 19

Describe how inflammation causes rubor (redness)

Answer 19

• Increased perfusion
• Increased vessel permeability
• Slow flow rate

Question 20

Describe how inflammation causes calor (heat)

Answer 20

• Increased perfusion
• Increased vessel permeability
• Slow flow rate

Question 21

Describe how inflammation causes tumour (swelling)

Answer 21

• Increased vessel permeability

Question 22

Describe how inflammation causes dolor (pain)

Answer 22

Mediated by prostaglandins and bradykinin

Question 23

What type of leukocyte characterises acute inflammation?

Answer 23

Neutrophils

and other types of granulocyte