Equine Wound Management Flashcards
What is examined for initial physical exams for wounds?
- abbreviated TPR
- observe wound from afar - closeness to synovial surfaces, freshness, contamination, fracture
- blood loss
- severe tachycardia
- lameness
- colic - horse may have injured itself while rolling to relieve pain
What 3 sedatives are recommended to allow a deeper exam of wounds?
- Xylazine
- Detomidine
- Butorphanol
What is used to aid in clipping around the wound without introducing new pathogens?
sterile lube or pack with wet gauze —> catches hair!
What 2 products are used to clean wounds? How are they lavaged?
- Betadine (0.1%)
- chlorhexadine (0.05%) - can use scrub in severe cases, but can be cytotoxic
lavage with saline in a 35-60 mL syringe with a 18/19 g needle —> reaches 15 PSI to wash away bacteria/debris without packing them in further
What are 2 options for local anesthesia for wound mangement?
- nerve blocks
- local infiltration - along cut skin edge, circumferential away from wound
What are indications of superficial digital flexors, deep digital flexors, and suspensory tendon involvement?
dropped fetlock
raised toe
90 degree flexion
What tendons are likely involved in this wound?
dropped fetlock = superficial digital flexor tendon
What tendons are likely involved in this wound?
dropped fetlock + raised toe = superficial digital flexor and deep digital flexor tendons
What tendons are likely involved in this wound?
dropped fetlock + raised toe + flexion = superficial digital flexor, deep digital flexor, and suspensory tendons
What is indicative of extensor involvement in wounds?
insert of P3 —> knuckling, able to bear weight (unlike flexors!)
What 4 treatments are indicated for wounds involving flexors? What is commonly not indicated?
- wound lavage
- coaptation
- physical therapy
- therapeutic shoeing
sx - apposition is difficult due to inability to take wide bites and increased tension
How does prognosis of flexor and extensor damage compare?
- superficial/deep - fair to good, 8-12 months healing
- suspensory - poor, likely all tendons severed, depends on vascular involvement
- extensors - good, able to bear weight, horse learns
(decreased prognosis if synovial and vessel involvement)
What adjacent structures are of concern in cases of cervical wounds? What commonly results?
- treachea
- veins, arteries, nerves
SQ emphysema - self-limiting, will resorb
What sequelae are associated with thoracic and abdominal wounds?
THORACIC - pneumothorax, septic pleuritis
ABDOMINAL - septic peritonitis, punctured viscera (likely need to euthanize on table)
What must be done to ensure proper healing of wounds in highly mobile areas? What is avoided?
immobilization
full distal limb casts = pressure sores common, increased maintenance necessary and commonly stay in hospital ($$$)
How are casts properly put on limbs?
- cast over bandage
- leave out toe to allow weight bearing
good TGH, decreased instance of pressure sores
What 3 things does tension at wound edges cause?
- vascular damage
- tissue necrosis
- dehiscence
How do the tension lines in horses lie? How does this affect wound closure planning?
vertical - proximal to distal
- wounds perpendicular to Langer’s lines have high tension and appear gaping on presentation
- wounds parallel to Langer’s lines have minimal gaping and can be closed with more normal appositional patterns
What are 3 options for relieving tension when closing wounds?
- everting suture patterns
- reduce edema - tack and pressure bandage prior to closing, tourniquet
- quills or stents
What are 3 options of tension relieving suture patterns? What is avoided?
- NFFN/FNNF - pulley action provides +++ tension relief, commonly use larger suture to avoid sawing of the skin
- vertical mattress - everts tissue edges for ++ tension relief
- (inverted) cruciate - interrupted, + tension relief
horizontal mattress - impedes blood supply, resulting in ischemia
What is the best way to approach skin flaps?
use split thickness bites turn the flap into more of a Y, which relieves tension
What are the 3 most common methods of wound debridement? What are 2 other options?
- sharp - scalpel
- mechanical - lavage at 15 PSI, wet to dry bandage + hypertonic saline
- autolytic - moist wound healing
+ chemical - enzyme-based
+ biological - sterile maggots
What are 2 indications for primary closure of wounds?
- apposition possible with minimal tension
- minimal contamination
What are 2 benefits to primary closure?
- decreased contamination, healing time, scarring, and aftercare —> less cost!
- improved cosmesis
What is delayed primary closure? What are 3 indications?
wound initially treated medically and closed within 3-5 days before granulation tissue is present
- mild/moderate contamination
- minimal tissue loss
- minimal tension
What is secondary closure? What are 2 indications?
treating a wound medically first and closing after granulation tissue develops
- chronic, gross contamination or infected tissue
- granulation tissue present
What is second intention healing? What are 3 indications?
leaving a wound open to heal + bandaging and medical therapy
- significant tissue loss
- contraction and epithelialization
- primary closure failed and dehisced
What location of wounds are most commonly left to second intention healing?
trunk/neck —> decreased elasticity, increased arterial supply
What are the 3 phases of second intention healing?
- INFLAMMATORY - stopping blood loss, preventing infection, substrate/cell signaling for further healing
- PROLIFERATIVE - angiogenesis, fibroplasia, granulation tissue, epithelialization, contraction
- REMODELING - collagen accumulation
How do edema and cellulitis compare?
EDEMA = swelling, not typically painful
CELLULITIS - infection of SQ tissues causing horse to become febrile, painful, and lame
What are the 5 most common signs of cellulitis? What are the 2 most common bacterial causes?
- significant swelling in one limb
- severe lameness (Grade 4-5/5)
- febrile
- no visible wound
- may weep fluid from skin or have skin sloughing
Staph + Srept (G- or anaerobes possible)
What 4 treatments are recommended for cellulitis?
- broad-spectrum antibiotics - SMZ, Doxycycline, Gentamicin, Enrofloxacin (refractory cases), Ceftiofur/Penicillin
- NSAIDs - Flunixin meglumine, Phenylbutazone
- hydrotherapy
- sweat bandage - Epsom salt, Nitrofurazone, DMSO + Seran wrap keeps a warm/moist environment for treatment (kept <24 hours)
What is indicative of chronic cellulitis? What is associated with decreased survival?
chronically thick leg (horses prone to recurrence!)
laminitis
What additional treatment is especially important for wounds? What may be associated with this treatment?
tetanus toxoid booster - given when vaccine was given more than 6 months from occurence
tetanus antitoxin associated with Theiler’s Disease
What are the 5 most common causes of non-healing wounds?
- infection
- FB
- necrotic tissue
- exuberant granulation tissue
- tissue transformation
How does infection cause non-healing wounds? What are the 4 most common causes?
arrests healing process
- Staph —> Botriomycosis
- Pseudomonas
- E. coli
- Enterobacter
What are the most common fungal and parasitic infections that cause non-healing wounds?
Pythius spp
Habronema - “Summer sores”
Non-healing wound:
necrotic tissue!
What kind of wounds most likely cause bone sequestrum? What are the 2 most common signs?
lacerations with exposed bone
- draining tract
- no healing over exposed bone
What causes formation of bone sequestrum in wounds?
periosteal damage from the wound causes a loss of blood supply to the affected bone, resulting in necrosis of the outer coretex
When is evidence of bone sequestrum seen on radiographs? How are they prevented and treated?
2-3 weeks post-injury
- PREVENTION = suture wound and cover bone, curette exposed bone
- TREATMENT = surgical removal of bone
What is proud flesh? What causes its formation at wounds?
exuberant granulation tissue in wounds
prolonged inflammation causes the proliferation phase to remain longer than usual, resulting in delayed contraction and prevention of epithelialization
What are 3 risk factors that lead to increased chances of proud flesh formation?
- distal limb - decreased tissue coverage and oxygen tension
- high movement areas
- large, open wounds
Healthy granulation tissue:
- pink
- bumps
What are 4 options for treating proud flesh? What should be avoided?
- sharp debridement - very vascular, no nerve endings, recommended if greater than the thickness of a dime (from bottom up)
- topical corticosteroids
- skin grafting
- equine amnion dressings
damage to healthy cells
Proud flesh:
What 2 skin transformations result in non-healing wounds?
- sarcoid
- SCC
