Abscess

Question 1

What is an abscess?

Answer 1

A collection of pus; a complication of acute inflammation

Question 2

What is acute inflammation?

Answer 2

The initial tissue reaction to injury

Question 3

What are the 4 signs of acute inflammation?

Answer 3

–Rubor (redness)

–Calor (heat)

–Tumor (swelling)

–Dolor (pain)

–Functio laesa (loss of function)

Question 4

What are the 3 phases of AI?

Answer 4

1. Vascular changes
2. Extravasation of WBCs
3. Phagocytosis

Question 5

What vascular changes occur during AI?

Answer 5

Initial vasoconstriction followed by dilation and increased vascular permeability

Question 6

What is extravasation of WBCs?

Answer 6

The movement of leukocytes out of the circulatory system and towards the site of tissue damage or infection.

Question 7

Describe the process of extravasation of WBCs?

Answer 7

• Organised sequential process
• Margination –> adhesion –> transmigration –> chemotaxis

Question 8

Blood vessel dilation diagram

Answer 8

Question 9

What is opsonisation mediated by?

Answer 9

IgG or C3

Question 10

Describe pathway of phagocytosis

Answer 10

• Opsonisation
• Engulfment
• Killing (by reactive oxygen species or myeloperoxidase)

Question 11

What is rubor (redness) in AI caused by?

Answer 11

Vasodilation

Question 12

What is calor (heat) in AI caused by?

Answer 12

Caused by hyperaemia (an excess of blood in the vessels) and systemic increase in temperature due to cytokines

Question 13

What is tumor (swelling) in AI caused by?

Answer 13

Caused by localised oedema

Question 14

What is dolor (pain) in AI caused by?

Answer 14

Caused by to cytokines (bradykinin, serotonin, prostaglandins) and physical pressure

Question 15

What is functio laesa (loss of function) in AI caused by?

Answer 15

Caused by pain and swelling

Question 16

What is suppuration?

Answer 16

The formation of pus:

• Living and dead neutrophils
• Cell/tissue debris
• Bacteria

Question 17

What is suppuration usually due to?

Answer 17

A bacterium (pyogenic bacteria)

Question 18

What can suppuration form?

Answer 18

An abscess - a collection of pus in the body eg. in an organ, soft tissue, skin

Question 19

Are abscesses accessible to antibiotics?

Answer 19

No

Question 20

How are abscesses usually managed?

Answer 20

Incision and drainage

• May pack with antiseptic soaked gauze to help “granulate”
• Send a sample to microbiology lab

Question 21

What does granulation tissue contain?

Answer 21

Capillaries, oedema, white cells and fibroblasts

Question 22

How is angiogenesis involved in healing and repair?

Answer 22

Plays a crucial role in wound healing by forming new blood vessels from preexisting vessels by invading the wound clot and organising in to a microvascular network throughout the granulation tissue

Question 23

What is VEGF?

Answer 23

Vascular endothelial growth factor (VEGF) is a signalling protein that promotes the growth of new blood vessels.

Question 24

What is ‘organisation’?

Answer 24

When resolution and regeneration are not possible, necrotic cells are replaced with collagen; this is termed organisation, or repair by scar formation.

Question 25

What is granulation tissue?

Answer 25

Tissue comprised of new connective tissue and tiny blood vessels that form on the surfaces of a wound during the healing process.

Question 26

Role of fibroblasts in granulation tissue?

Answer 26

These proliferate in granulation tissue and secrete ECM and collagen (FGF)‏

Fibroblast contraction then shrinks the wound

Question 27

Benefits of scar formation?

Answer 27

Prevents infection and protects against mechanical trauma

Question 28

Negative effects of scar formation?

Answer 28

Stops regeneration

Question 29

Exudate histology

Answer 29

Question 30

What is margination?

Answer 30

Adhesion of WBCs to walls of damaged blood vessels

Question 31

Granulation and fibrosis histology

Answer 31