Equine wounds Flashcards
What type of necrosis do acids vs alkalis cause
Acids cause coagulation necrosis
Alkalis cause liquefaction necrosis
what are the 3 stages of wound healing
Inflammatory phase; = immediate and for a few days
Proliferative phase; angiogenesis, granulation, epithelialisation and contractino
Maturation/remodelling; scar tissue formation
How to prepare a wound
Before clipping hair must coat wound surface with KY jelly
Best to use isotonic saline to wash the wound; avoid using hibi/PI on the wound suface
Why do we often get dying off of upwards V flap tissue and should we keep it
most blood supply comes from proximal to distal so this area will be poorly vascularised as most blood supply cut off
Will likely necrose
But good to keep as it can act as a biological dressing to cover the wound
Why do we need to appose lesions on the coronary band in horses
To prevent hoof abnormalities forming
What is delayed primary wound closure
Where a wound is left a few days to give time for removal of contamination before closing up
When do we need to use second intention heling
Very contamined or large skin defects that can’t be closed primarily
What is best for suturing equine skin
Monofilament materials e.g nylon, PDS, prolene
What factors affect wound healing
Contamination
Tension
Vascularity
Dead space
Motion
What are some issues with using drains
act as a foreign body
Can be a wick for infection
How does wound infection delay healing and what factors predipose a wound to infection
Bacteria prolong inflammatory phase and produce collagenases which reduce wound strength
Predisposed to by: devitilised tissue, FBs, haematoma/seroma/dead space, movement, excessive oedema
What is a good dressing type for open wounds
Hydrogens to give moist environment
When might we use corticosteroids on wounds
Chronic wounds with exuberant granulation tissue
What is proud flesh
Excessive granulation tissue which is higher than the skin margin therefore making it hard for epithelium to grow over it
What would a mature granulation bed with a cleft or draining tract present make you suspicious of
Bony sequestra acting as a foreign body
How can we deal with excessive granulation tissue
Topical corticosteroids if not infected
Surgical excision under sedation and local anaesthesia
What type of graft thickness are normally done in horses and what does this mean
Usually full thickness i.e epidermis and whole dermis
Difference in how fresh tissue/granulation tissue accepts skin grafts
Fresh tissue accepts best > new granulation tissue > mature granulation tissue
BUT can’t do pinch punch grafts onto fresh tissue
Preparation of recipient wound bed for skin grafting
Culture and sensitivity
Topical antibiotics for 2-3 days pre-graft
Excise excess granulation tissue 2-3 days before grafting
Pinch island graft
= small discs of skin harvested by hand using scalpel blade
Punch island graft
= full thickness plugs of skin harvested using skin biopsy tool
Expected survival of pinch/punch grafts
60-75%
When might we do split vs full thickness grafts
Split thickness = epidermis and. just portion of dermis; needs specialist equipment
Full thickness = whole epidermis and dermis and done on yard; but not accepted as well
When might we choose to do a tunnel graft
For large skin defects esp in mobile sites or if hard to bandage
When might horses not present as too painful ddespite synovial sepsis
If the synovial structure is open and draining so there is no build up of pressure
When do we se haematogenous spread of bacteria leading to synovial sepsis
Mainly in foals with failure of passive transfer
How do we diagnose synovial sepsis
synoviocentesis
Treatment of cellulitis
Broad spectrum antibiotics, NSAIDs, bandaging, forced walking, cold hose therapy, lancing of any micro-abscesses
How do horses with synovial sepsis typically present
Afebrile
Variable lameness
Normal synovial fluid characteristics
Straw coloured
Viscous
Low white cell count; <10x10^9/L
White cells are low proportion neutrophils <15%
Low total protein <10g/L
Synovial fluid characteristics in a septic joint
Red (sero-sanguinous), cloudy
Watery
High white cell count; >20x10^9/L
White cells are high proportion neutrophils >90%
High total protein >30g/L
Treatment of synovial infections
Must be rapid and aggressive
Gold standard is synovial lavage via arthroscopy
+ broad spectrum antibiotics; systemic and local
Bandaging
Stall rest
Prognosis for synovial infections
90% survival with gold standard treatment
50-70% return to athletic functino
With conservative treatment very poor prognosis
What do we classify infection as in terms on amount of bacteria/g tissue
> 10^5 bacteria/g tissue
What pathogen is typically involved in iatrogenic synovial sepsis
Staphs
What antibiotics to use to treat synvial sepsis systemically and locally
Systemicaly: penicillin + gentamycin
Local: aminolycoside i.e gentamycin
