Principles of Wound Care

March 28, 2011 by
Filed under: Articles, Emergency, Laceration, Skin 

Tawna Purcell DVM

Horses can get themselves into a variety of trouble causing an equally large variety of wounds. Not all wounds will require the same care.  They can range from superficial scrapes to complicated lacerations. Regardless of the severity of the wound, the first thing to do is to thoroughly evaluate it and the horse to determine if prompt veterinary attention is required.  Wounds near joints, the eye, down to bone, involving tendons, possible foreign bodies, severe lameness or bleeding, etc. should be evaluated immediately by a veterinarian.

The approach to wound care will vary based on the type of wound at hand; whether it needs sutures, drain placement, debridement, extensive cleaning, casting or joint lavage.  We have many helpful tools to help us accomplish the best outcome of wound treatment.  Based on the patient, the location and the character of the wound we can choose from 3 general categories of wound closure.

Primary Wound Closure: If a wound is fresh, clean and in a good location suturing will often lead to good healing with a desirable cosmetic outcome.  However we often find wounds more than a few hours old and often contaminated with dirt and grime.  This is where we can employ delayed primary closure.

Delayed Primary Closure: If a wound is contaminated, we can utilize materials to decrease swelling and clean the wound a few days prior to suturing and/or casting.  A common dressing combination would be a hypertonic saline dressing (used to decontaminate and debride) underneath a cotton combine pressure wrap to decrease swelling.  The bandage is changed every 24-48 hours until contamination is under control to allow suturing or casting. An example of a common wound would be a heel bulb laceration.

Second Intention Healing: Used in wounds that are not amenable to suturing, or where suturing has failed. Although this technique has a wide variety of modalities to be used based on the wound, a commonly involved concept is moist wound healing.  When kept in a moist environment re-epithelialization (skin growth) occurs much faster than wounds exposed to air, as well as being less itchy, less inflamed, lower pain, shortened wound healing time and with less scarring.

In combination with certain bandage materials, the natural exudate of the wound can provide the best environment for healing, however there are instances such as burns and dry wounds that need help in the form of a topical dressing (such as Hydragels). Anti-microbial gauze dressing (AMD) can be used as an antibacterial barrier that will also absorb exudate while stimulating tissue growth. If the wound is heavily exudative calcium alginate dressing can absorb up to 20 times its weight in exudate while stimulating tissue growth, decreased bandage changes and decreased pain.

Excessive granulation tissue (proud flesh) can occur during wound healing, especially in the lower limbs. This can be challenging to address at times and there are many remedies out there. Depending on the amount of tissue present, de-bulking in combination with topical steroids and hydrophilic foam dressing under a pressure wrap is an excellent way to go. The hydrophilic foam dressing (COPA pad) does not allow granulation tissue to penetrate it, limiting its growth while also providing an excellent environment for normal healing.

Eye Injuries

Hunter Ortis, DVM
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The most frequent eye related problems in horses are corneal ulcers (abrasions to the surface of the eye), eyelid lacerations and uveitis. Clinical signs of an eye emergency include excessive tearing or discharge, spasmodic squinting, holding the eye partially or completely closed, or constriction of the pupil. Additionally, changes in appearance of the eye and its surrounding structures such as swelling of the eyelids, increased redness of the usually pink tissue around the eye, and cloudiness of the cornea are signs of an eye problem.

The most common injury of the eye is a corneal ulcer.  Ulcers occur when the surface of the eye comes in contact with a foreign object such a hay stem, stick or surface of a stall wall, leaving a defect in the integrity of the surface of the eye.  A horse with a corneal ulcer will usually have symptoms of a painful eye and/or a hazy bluish appearance of the surface of the eye.  Corneal ulcers are diagnosed with a fluorescing stain applied directly to the cornea during examination.  Treatment usually includes topical antibiotics because the cornea is easily infected.  Other medications may be indicated on a case by case basis.

Eyelid lacerations are commonly caused when the eyelid simply gets snagged on a piece of stall hardware, an overlooked raised nail or piece of wire.  These injuries are much easier to diagnose than most other eye emergencies but are equally important to seek rapid veterinary attention. Most lacerations involving the margin of the eyelid will require repair with suture.  The integrity of the eyelid margins is vital for maintaining a proper tear film on the surface of the eye.  An irregular eyelid margin can cause recurring and chronic eye irritation.

Uveitis, or inflammation in the interior portion of the eye, occurs when inflammatory mediators are released causing leakage of damaging proteins into the internal structures of the eye. There are many different causes of uveitis including blunt or penetrating trauma, corneal ulcers, systemic diseases, and unknown causes to name a few.  Most horses with uveitis will show signs of a painful eye that appears cloudy.  Diagnosis is usually made with findings from a complete eye examination including the use of an ophthalmoscope.  Rapid and aggressive treatment, often with multiple topical and systemic medications, is essential in minimizing the possibility of permanent damage to the internal structures of the eye.

Injuries of the equine eye should be considered an emergency, and owners should consult their veterinarian immediately when a potential problem has been identified.  Delaying treatment or instituting improper treatment on some ocular conditions can lead to permanent damage to the eye and loss of vision.

Cellulitis

December 21, 2009 by
Filed under: Cellulitis, Emergency, Joint, Laceration, Lameness 

Nathan Voris, DVM
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Anyone with a horse has likely walked out to find them with a swollen, painful leg.  While there are countless reasons for a horse to become “stoved-up” or “stocked-up”, one of the most common is cellulitis.

Cellulitis can be literally defined as inflammation of subcutaneous tissues.  Many times, a cause for the swelling cannot be found, but some common reasons for cellulitis include “scratches” (pastern dermatitis), blunt trauma, lacerations or small puncture wounds.  Inflammation, with or without bacterial infection, that is trapped under the skin, is clinically expressed as heat and swelling of the affected tissues thus resulting in a swollen, painful leg.  Many times the horse will be severely lame and might even have a fever.

Treatment of cellulitis often includes hydrotherapy, sweat/pressure bandaging, anti-inflammatories and antibiotics.  Efforts should be made to find the inciting injury as other diagnostic tests or treatments might be required to adequately treat the horse’s condition and to check the integrity of underlying bone and soft tissues.

Lacerations Involving Joints

August 7, 2006 by
Filed under: Articles, Emergency, Joint, Laceration, Lameness, Skin 

Nathan Voris, DVM
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Anyone who has owned a horse knows the term “horse-safe” is an oxymoron; many horses could find a way to hurt themselves in a barn with padded stalls. In equine practice, lacerations represent one of the most frequent emergency calls. Most of the time, the wound is in a benign area that can be easily cleaned up and sutured. Other times, location of the wound combined with critical structure involvement forbids simple primary closure and calls for aggressive medical and possible surgical intervention to facilitate healing.

There are very few wounds that are as threatening to a horse’s career, or even life, than one that involves a joint. The reason for this is the anatomic and physiologic makeup of the joint itself. Beneath the skin, the joint is protected by a fibrous tissue structure called the joint capsule. On the inner side of the joint capsule is a tissue layer that produces synovial fluid. The synovial fluid is responsible for lubricating and nourishing the joint surfaces. Unfortunately, the properties that allow synovial fluid to nourish the joint also make it a perfect medium for bacterial growth if the protective layers are penetrated.

The body’s natural response to a wound is to send scavenging white blood cells to “clean up” damaged tissue and bacteria. This is the reason a joint may become swollen, hot and painful following an injury. Unfortunately, the body’s response to injury is almost as bad as the infection itself because the flood of white blood cells into a joint can lead to cartilage breakdown. The longer the infection lasts, the more likely there will be significant permanent damage to the joint.

Intra-articular irrigationLacerations near joints warrant immediate thorough evaluation by a veterinarian to assess the extent of tissue involvement. If the injury is recent and there is minimal subcutaneous inflammation (cellulitis) a needle should be inserted into the joint, on the side opposite the wound, and sterile saline should be injected to distend the joint. If saline from within the joint leaks out through the wound, the joint should be considered infected and aggressive treatment should be initiated.

Appropriate treatment involves intra-articular irrigation, broad spectrum systemic and intra-articular antibiotics, systemic anti-inflammatories, and sterile bandaging. Most of the time, the wound should not be closed with sutures due to the risk of sealing bacteria into the joint or surrounding tissues. Duration of treatment is solely dependant upon the horse’s response to treatment. If appropriate treatment is initiated within 24 hours of injury, horses have an 85% chance of survival and 50% chance of returning to full function.

Sometimes a cut that appears to be “a long way from the heart” can be a big problem but rapid identification of joint involvement and aggressive medical and surgical care can tip the odds in your favor for a positive outcome.