Equine wound healing Flashcards
what are the main components of skin?
collagen (strength)
elastic fibres
ground substances
what layers make up the epidermis?
stratum corneum
stratum granulosum
stratum spinosum
stratum basale
what layers make up the dermis?
superficially papillary layer
deep reticular layer
what are the cellular mediators of wound repair?
growth factors
cytokines/chemokines
what are the three phases of wound healing?
inflammatory/lag
proliferative
remodelling
what are the three things that happen during the inflammatory stage of wound healing?
haemostasis
protect against infection
cellular signals for next step
what happens after the initial transient vasoconstriction in the inflammatory stage?
vasodilation (heat, redness, swelling)
what acts as a meshwork for other cells to bind to in the inflammatory stage of healing?
fibrin
what are the key cells involved in the inflammatory phase of wound healing?
neutrophils, monocytes (macrophages)
what four processes occur in the proliferative stage of wound healing?
angiogenesis
fibroplasia/granulation tissue formation
epithelialisation
contraction
what are the aims of the proliferative phase of wound healing?
permanent closure of wound
replace lost tissue
what does the duration of the proliferative phase of wound healing depend on?
wound size/location
age
health of individual
what do fibroblasts transform into towards the end of the proliferation phase?
myofibroblasts (contraction)
what happens to collagen during the remodelling phase of wound healing?
strengthening/remodelling
how does wound healing in ponies and horses differ?
horses have slower wound healing of distal limbs
what local factors influence wound healing?
wound perfusion tissue viability fluid accumulation infection mechanical factors (movement)
what systemic factors can influence wound healing?
immunology
systemic conditions - obesity, malnutrition…
external agents
what are examples of closed wounds?
crush injuries
bruise (contusions)
haematoma
what is an abrasion/erosion?
superficial loss of surface epithelium without exposure of underlying dermis
what is the primary way abrasions/erosions heal?
mitotic division of epithelial cells (no inflammatory cells or angiogenesis)
what is an ulcer?
loss of surface epithelium with exposure/damage to underlying tissue
how are burns classified?
depth (degree)
extent (% of body surface)
what are the classifications of a wound based on degree of contamination?
clean
clean contaminated
contaminated
dirty
what is a clean wound?
surgical wound not entering respiratory, urogenital or GI tracts with no aseptic breaks
what is a clean contaminated wound?
surgical wound involving the respiratory, urogenital or GI tracts without major contamination or a small break in asepsis
what is a contaminated wound?
traumatic wound <6 hours old
surgical wound with significant respiratory, urogenital or GI contamination
surgery with inflammation present
major break in asepsis
what is a dirty wound?
traumatic wound >6 hours old
surgery with abscessation
traumatic wounds with foreign bodies or devitalised tissue
perforation of hollow viscus
when clipping a wound to assess it, what precaution should be taken?
apply sterile gel to wound to prevent hair/dirt entering
what can be used to lavage wounds?
saline/tap water
chlorhexidine (dilute - 0.05%)
povidone iodine (dilute)
what bacteria is particularly important to remember when assessing wounds in horses?
tetanus (Clostridium tetani)
what are the types of wound healing?
first intention (primary closure) second intention third intention (delayed primary closure)
what is first intention (primary closure) of wounds?
wound immediately and completely closed
what is needed for closure of a wound by first intention (primary closure)?
minimal bacterial contamination
removal of devitalised tissue/foreign bodies (debridement)
no dead space/ischaemia
what is wound healing by second intention?
open wound with regular wound care allowing granulation tissue to form
what is delayed primary closure of a wound?
open wound that is then closed after debridement and reduction of bacterial contamination
