Equine Wound Healing Flashcards
What stage is prolonged in delayed wound healing? What are 6 common causes?
Prolonged inflammatory stage -> delayed proliferation and remodeling stages
- The wound is infected (bacteria, fungal, parasitic) -> body has to work harder to clear it out
- Motion (interrupts wound contraction or the newly laid granulation tissue)
- Cells of NON-HEALING wound can transform into sarcoid or SCC
- Foreign body in wound can interfere with wound contraction and cause a 2º infection (Wood = 59%!)
- Bone sequestrum (potentially interferes with blood flow?)
- Necrotic tissue (impairs blow flow / cell regeneration)
Important aspect of the physical exam?
Careful palpation of all deep, surrounding structures (joints, tendons, bone, etc.) and of the wound itself -> septic arthritis = concern any time there is a synovial structure near a wound!
What diagnostic techniques are typically performed?
Synoviocentesis; radiographs, u/s
What is the Initial Management of treatment comprised of?
ensuring that the environment is appropriate to allow for a full, proper wound assessment (safety; analgesics, chemical restraint)
What wound cleansers are used in debridement?
Lavage with non-cytotoxic solution (isotonic 0.9% NaCl; tap water; chlorohexidin or betadine solution)
Never use hydrogen peroxide or scrub!! H2O2 and the detergent in scrub are toxic to fibroblasts!
Why most primary closure be used selectively in horses?
Distal limb wounds often become dehisced -> therefore, use primary closure for select wounds like facial lacerations and limb wounds where immobilization is ensured post-operatively
Which wound closure technique is most commonly used in hroses?
Second Intention - lower limb wounds, high-motion areas; extensive tissue trauma, contamination
second intention: non-surgical closure. allows for granulation tissue to be deposited into wound core -> scaffloding for re-epithelization / contraction -> visible scar
- when the wound edges cannot be approximated and the wound needs to heal from the bottom.
What is a common consequence of second intention healing of distal limb wounds?
Exuberation Granulation Tissue: granulation continues to grow even when the wound gap has filled -> wound contraction is delayed and epithelial migration is inhibited
Occurs b/c there is dysregulation in fibroplasis: the transition of fibroblast phenoytype into its contractile phenotype, myofibroblast, is DELAYED! EGT is also caused by chronic inflammation // stimulated by bandage application.
Horses > Ponies
In non-EGT-healing wounds, fibroblast & myofibroblast growth ceases once wound contraction ends, via apoptosis -> EGT interferes with this regimen // apoptosis!
What are 2 ways to manage exuberant granulation tissue?
- Trimming of exuberant tissue (stimulate wound contraction & epithelialization)
- Judicious use of triamincolone oinement (removes water content/swelling -> removes physical barrier impeding contraction and epithelialization) -> can inhibit epithelialization! so use carefully and avoid applying @ wound margins!
Use the ointment BEFORE EGT is severely exuberant!
Where are punch grafts implanted into in a wound? What are the benefits of this type of grafting?
Into the newly laid granulation tissue (e.g., 3 weeks after cast removal)
Benefits: easy, inexpensive, can be performed on a standing horse
A horse presents for severe lameness following a distal limb wound laceration. Upon palpation, you feel heat, effusion & soft tissue swelling. You suspect septic arthritis of the synovial structure and begin your emergency, aggressive treatment.
- What do you suspect to see in the synovial fluid analysis?
- How will you treat?
Synovial fluid analysis
- increased TNCC, bacteria
- dark yellow, turbid, hyperproteinemia (foamy)
- pleocytosis
- neutrophilia (degranulated or toxic)
Tx
- wound lavage / debridement, drainage
- systemic and regional ABX
What are the benefits of regional antibiotic delivery?
- ABX administed IA or IV directly to region of the wound
- drug accumulates in high concentrations & systemic toxicity is avoided
aminoglycosides; ceftiofur
