Burns in horses
Burns in horses can be caused by a horse being trapped within a burning barn/stable, a road traffic accident, electrocution or lightning strike, or contact with hot water or chemicals. The extent of tissue damage depends upon temperature, duration of exposure, local wound environment, and blood supply. Severe burns are followed by “burn shock”, which resembles hypovolemic shock, with a dramatic increase in vascular permeability and release of various mediators (cytokines, prostaglandins, NO, vasoactive leukotrienes, serotonin, histamine and ROS).
Clinical signs
Horses with burns may have a scorched coat or be covered in soot. There will be varying degrees of skin injury from erythema to skin sloughing with or without involvement of underlying issues. Corneal damage, like blepharospasm or epiphora, is also possible. Dyspnea and coughing are likely due to smoke inhalation. If the burns are severe and extensive, the patient may display weakness, tachycardia, dehydration, shock or collapse.
Diagnosis
A complete clinical examination to assess the condition of the patient and wounds should be addressed only after stabilization. The extent of the burn depends on the area exposed, and the severity depends on the maximum temperature and duration of the overheating. Heat is slow to dissipate in burn wounds, so early evaluation may not be accurate. A complete blood count may reveal anemia that can be severe and progressive. Serum biochemistry testing may show low total protein, low albumin, renal failure and hemolysis. Electrolyte testing may show hyperkalemia in early phases, followed by hypokalemia. Other useful testing includes a clotting profile, arterial blood gases and carbon monoxide concentration, a hemoglobinuria urine analysis, chest radiographs, bronchoalveolar lavage and blood pressure monitoring.
Treatment
The patient should be stabilized before the wounds are treated. Blankets (rugs) and wraps (stable bandages) must be removed to avoid holding heat next to the animal. Cooling the horse with lukewarm water may help within the first few minutes but the use of ice or cold water could be contraindicated. Treat for shock and respiratory signs and administer pain relief with NSAIDs and sedatives if necessary.
First degree burns should be treated with cool compresses, cold-water and wound coverings. Second degree burns should be treated by leaving vesicles intact for 24-36 hours (blister fluid protects from infection). After such time, partial excision of the blister and application of an antibacterial dressing (silver sulfadiazine) are recommended to allow eschar formation. In third degrees burns, if the dermis is destructed, the aim of the treatment is to keep the wound dry (bacteria do not thrive on a dry surface) and protected from trauma. This method has the disadvantage of heat and water loss. The choice of treatment depends on the extent and location of the wounds. Full thickness burns can be managed by occlusive dressings, continuous wet dressings, eschar formation, or excision and grafting. The most practical and effective technique for large burns in horses is the open method.
Other options post-burn include immediately applying a dressing with calcium alginate and acemannan hydrogel mixed with topical antibiotics, to keep tissues moist preventing further eschar formation.
Other topicals include aloe vera (for pain relief, anti-inflammatory and antimicrobial activity, although it may delay healing after inflammation is controlled), mafenide acetate, chlorhexidine, povidone-iodine, and gentamicin sulfate ointment.
Short-term prophylactic IV antimicrobials may be indicated immediately post-burn, only if more than 100,000 cells/g of tissue are obtained with quantitative biopsy cultures, or another rapid slide dilution method.
Prognosis
The outcome is variable depending on the extent and degree of injuries. Delays or complications of second intention healing may limit the return of the horse to its previous activity. For horses with deep partial- or full-thickness burns involving 30%-50% of the body, euthanasia should be recommended.
References
Content provided from Vetstream's Vetlexicon Equis - https://www.vetlexicon.com/equis
Vetlexicon is the world’s largest peer-reviewed online clinical reference source. All our content is written and peer-reviewed by over 1,000 of the world’s leading veterinarians, ensuring relevance, accuracy and quality.