Equine wound healing

Question 1

what are the main components of skin?

Answer 1

collagen (strength)
elastic fibres
ground substances

Question 2

what layers make up the epidermis?

Answer 2

stratum corneum
stratum granulosum
stratum spinosum
stratum basale

Question 3

what layers make up the dermis?

Answer 3

superficially papillary layer

deep reticular layer

Question 4

what are the cellular mediators of wound repair?

Answer 4

growth factors

cytokines/chemokines

Question 5

what are the three phases of wound healing?

Answer 5

inflammatory/lag
proliferative
remodelling

Question 6

what are the three things that happen during the inflammatory stage of wound healing?

Answer 6

haemostasis
protect against infection
cellular signals for next step

Question 7

what happens after the initial transient vasoconstriction in the inflammatory stage?

Answer 7

vasodilation (heat, redness, swelling)

Question 8

what acts as a meshwork for other cells to bind to in the inflammatory stage of healing?

Answer 8

fibrin

Question 9

what are the key cells involved in the inflammatory phase of wound healing?

Answer 9

neutrophils, monocytes (macrophages)

Question 10

what four processes occur in the proliferative stage of wound healing?

Answer 10

angiogenesis
fibroplasia/granulation tissue formation
epithelialisation
contraction

Question 11

what are the aims of the proliferative phase of wound healing?

Answer 11

permanent closure of wound

replace lost tissue

Question 12

what does the duration of the proliferative phase of wound healing depend on?

Answer 12

wound size/location
age
health of individual

Question 13

what do fibroblasts transform into towards the end of the proliferation phase?

Answer 13

myofibroblasts (contraction)

Question 14

what happens to collagen during the remodelling phase of wound healing?

Answer 14

strengthening/remodelling

Question 15

how does wound healing in ponies and horses differ?

Answer 15

horses have slower wound healing of distal limbs

Question 16

what local factors influence wound healing?

Answer 16

wound perfusion
tissue viability
fluid accumulation
infection
mechanical factors (movement)

Question 17

what systemic factors can influence wound healing?

Answer 17

immunology
systemic conditions - obesity, malnutrition…
external agents

Question 18

what are examples of closed wounds?

Answer 18

crush injuries
bruise (contusions)
haematoma

Question 19

what is an abrasion/erosion?

Answer 19

superficial loss of surface epithelium without exposure of underlying dermis

Question 20

what is the primary way abrasions/erosions heal?

Answer 20

mitotic division of epithelial cells (no inflammatory cells or angiogenesis)

Question 21

what is an ulcer?

Answer 21

loss of surface epithelium with exposure/damage to underlying tissue

Question 22

how are burns classified?

Answer 22

depth (degree)

extent (% of body surface)

Question 23

what are the classifications of a wound based on degree of contamination?

Answer 23

clean
clean contaminated
contaminated
dirty

Question 24

what is a clean wound?

Answer 24

surgical wound not entering respiratory, urogenital or GI tracts with no aseptic breaks

Question 25

what is a clean contaminated wound?

Answer 25

surgical wound involving the respiratory, urogenital or GI tracts without major contamination or a small break in asepsis

Question 26

what is a contaminated wound?

Answer 26

traumatic wound <6 hours old surgical wound with significant respiratory, urogenital or GI contamination surgery with inflammation present major break in asepsis

Question 27

what is a dirty wound?

Answer 27

traumatic wound >6 hours old surgery with abscessation traumatic wounds with foreign bodies or devitalised tissue perforation of hollow viscus

Question 28

when clipping a wound to assess it, what precaution should be taken?

Answer 28

apply sterile gel to wound to prevent hair/dirt entering

Question 29

what can be used to lavage wounds?

Answer 29

saline/tap water chlorhexidine (dilute - 0.05%) povidone iodine (dilute)

Question 30

what bacteria is particularly important to remember when assessing wounds in horses?

Answer 30

tetanus (Clostridium tetani)

Question 31

what are the types of wound healing?

Answer 31

``` first intention (primary closure) second intention third intention (delayed primary closure) ```

Question 32

what is first intention (primary closure) of wounds?

Answer 32

wound immediately and completely closed

Question 33

what is needed for closure of a wound by first intention (primary closure)?

Answer 33

minimal bacterial contamination removal of devitalised tissue/foreign bodies (debridement) no dead space/ischaemia

Question 34

what is wound healing by second intention?

Answer 34

open wound with regular wound care allowing granulation tissue to form

Question 35

what is delayed primary closure of a wound?

Answer 35

open wound that is then closed after debridement and reduction of bacterial contamination