Common emergencies involving the musculoskeletal system of horses include fractures, luxations, lacerations, puncture wounds, synovial infections, and exertional rhabdomyolysis. Wounds must be evaluated and the structures involved identified via radiography and synoviocentesis. Musculoskeletal emergencies are managed with antimicrobials, bandages, and splints. Although many of these conditions cannot be treated in the field, accurate diagnosis and appropriate emergency treatment are essential for a successful outcome.
Fractures and Luxations in Horses
A thorough physical examination is warranted in horses with suspected fractures or luxations; however, the examination can be complicated by the severity of the injury and other factors (eg, pain, anxiety, exhaustion, dehydration, owner/trainer anxiety). This type of injury should be suspected if a loud crack is heard; if there is acute, non-weight-bearing lameness; if the limb has an abnormal angulation; or if the limb is visibly unstable.
The goals of initial coaptation are to relieve anxiety, prevent further injury, and enable safe transportation for evaluation and possible definitive treatment. Initial coaptation of unstable limbs should precede radiographic evaluation or transportation to a surgical facility.
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Initial Assessment
Examination and Identification of the Injury
The extent of physical examination to assess fractures or luxations in horses should be dictated by the situation, to avoid further injury to the patient or bystanders:
If the patient is recumbent, the limb should be fully assessed before attempts to stand the horse up.
If the horse is standing, the limb should be fully examined before attempts to move the horse.
With an unstable fracture, the limb should be stabilized before any other treatment or diagnostic procedure.
Restraint for Evaluation
Sedation or a twitch can help restrain the horse for examination.
An alpha-2 agonist such as xylazine or detomidine can be administered for sedation. Because alpha-2 agonists often cause the horse to lean forward, which can increase the weight on an injured forelimb, the minimal effective dose is preferred. After maximal exercise or when the horse is excited, however, effective sedation can require a higher dose.
Butorphanol, methadone, or other opioids can supplement the sedation protocol for horses not well controlled by alpha-2 agonists alone. Because of its hypotensive effects, acepromazine should be reserved for horses with normal blood volume. If the horse is recumbent and a serious injury is suspected, general anesthesia can be safely induced via sedation with an alpha-2 agonist followed by induction with ketamine and diazepam/midazolam or tiletamine-zolazepam.
Before sedation or anesthesia, the patient's circulatory system—heart rate, mucous membrane color, capillary refill time, and pulse quality—should be assessed briefly. Heart rate > 80 bpm, accompanied by prolonged capillary refill time and poor peripheral pulse quality, indicates the need for IV fluid therapy.
Laboratory-determined biochemical tests are becoming more commonly available in field situations with point-of-care equipment. If available, bloodwork to evaluate hydration and electrolyte balance is useful to dictate fluid volume and type (see Emergency Fluid Therapy).
External Coaptation
For limb stabilization, it is useful to divide injuries into four categories, which help define the method of coaptation:
Level 1 injuries involve the distal metacarpus/metatarsus and phalanges and include injuries to the fetlock joint and extensor and flexor tendon at the level of the metacarpus and metatarsus.
Level 2 injuries involve the mid-metacarpus to distal radius, carpal joint, and mid- to proximal metatarsus.
Level 3 injuries involve the mid- to proximal radius in the forelimb or tarsus and tibia in the hindlimb.
Level 4 injuries are noted in the forelimb proximal to and including the elbow joint, or in the hindlimb proximal to and including the stifle joint.
Diagnosis of Orthopedic Injuries
Joint instability
Crepitus
Abnormal limb angulation
Palpation of bone fragments
Direct visualization of the fractured bone
Luxation should be suspected when there is abnormal motion at the level of a joint. Radiographic evaluation is indicated to confirm the presence or absence of a fracture or luxation, but only after coaptation has been applied. Four standard radiographic views should be obtained:
For the forelimb: anterior-posterior (or dorsopalmar), lateral, dorsolateral-palmaromedial oblique (DLPMO), and dorsomedial-palmarolateral oblique (DMPLO)
For the hindlimb: anterior-posterior (or dorsoplantar), lateral, dorsolateral-plantaromedial oblique (DLPMO), and dorsomedial-plantarolateral oblique (DMPLO)
Confirmation of joint luxation can require stressed views. Additional views may be needed to identify the fracture planes.
If radiographic equipment is unavailable on-site, the horse should be coapted and transported to a referral facility for further examination. Hairline or stress fractures can be difficult to demonstrate radiographically, especially in field conditions. Therefore, when severe lameness with pain is localized to a long bone, external coaptation should be applied before the horse is moved, to avoid catastrophic displacement of an incomplete fracture.
Goals of Management of Acute Orthopedic Injuries
The initial management of traumatic injuries aims to relieve anxiety, immobilize the fracture or luxation for transportation, prevent further tissue damage, and enable safe transportation. Emergency coaptation is indicated only for short-term limb immobilization. Splints alone are not considered the standard of care for longterm treatment of orthopedic injuries in horses and are not adequate for fracture healing in most situations.
The goals of emergency coaptation include the following:
appropriate wound care
prevention of skin abrasions through adequate padding
immobilization of the joint above and below the area of injury
prevention of movement
Wounds should be carefully cleaned and debrided. A nonadherent bandage can be applied and held in place with conforming gauze. Cotton padding is applied to the entire length of the segment to be immobilized and held in place with inelastic gauze, followed by elastic cohesive bandage material. The bandage should be snug so that it won't loosen as the cotton material compresses, and each layer should be applied individually.
Splints are then applied and held in place with heavy tape (duct tape or medical white tape). Fiberglass casting tape can also be used. Splints must be well padded to avoid the development of sores. In addition, splints must never end in the middle of a long bone or at the end of a fracture line, to avoid causing a stress riser and increasing the risk of iatrogenic fractures.
Immobilization of Level 1 Injuries
Level 1 orthopedic injuries include the following:
phalangeal fractures
distal metacarpal and metatarsal fractures
sesamoid fractures
fetlock, pastern, and coffin joint luxations
flexor tendon disruption
Fractures of the coffin bone are not included in this category, because they are supported by the hoof capsule and do not require a splint. Although technically level 1 injuries, extensor tendon lacerations require a different mode of splint application and are discussed separately below. Forelimb and hindlimb immobilization differ slightly because of the presence of the reciprocal apparatus in the hindlimb.
Level 1 Forelimb Injuries
In level 1 forelimb injuries, immobilization is best accomplished by aligning the cannon bone with the phalanges to establish a straight, weight-bearing column. The horse will bear some weight on its toe.
To bandage the limb, an assistant holds the leg by the radius, allowing the limb distal to the carpus to hang in a straight line to facilitate bandaging (see distal forelimb level 1 PVC splint image).
Courtesy of Dr. Amelia Munsterman.
A modified Robert Jones bandage is placed using roll cotton or a combine bandage, brown gauze, and elastic bandaging material to form a light bandage that will protect skin but allow for soft tissue swelling. Each layer of bandaging material is wrapped separately and in the same direction to prevent shifting of the splint.
A splint is applied to the cranial aspect of the limb, extending from the point of the toe to the carpal-metacarpal joint, using four to six layers of overlapping, nonelastic tape (eg, white medical tape or duct tape). The splint should be padded proximally to prevent skin injury. If lateral to medial instability is noted, a lateral splint can be added or casting tape applied over the splint.
Level 1 Hindlimb Injuries
Splint placement for level 1 injuries in the hindlimb can be similar to that in the forelimb. However, the reciprocal apparatus prevents extension of the distal limb if the horse is non-weight-bearing. Therefore, the limb is better immobilized if the splint is applied on the caudal aspect of the limb, from the point of the toe on the plantar aspect of the hoof up to the point of the hock (see distal hindlimb level 1 PVC splint image).
Courtesy of Dr. Amelia Munsterman.
Dorsal alignment of the bony column is not possible and not necessary for adequate hindlimb coaptation. Bandaging and splinting techniques are otherwise similar to those used for the forelimb.
Commercially Available Coaptation
Commercially available metal splints can be used for some level 1 fractures or tendon injuries (see distal forelimb level 1 metal splint image); however, they do not provide lateral-to-medial stability for joint luxations or severely comminuted fractures. Commercial splints are available in a number of sizes, easy to apply, and effective for immediate immobilization.
Courtesy of Dr. Amelia Munsterman.
Two configurations of commercial splints are available: one with a slightly forward-angled bar for a flexed position of the forelimb, and one with a backward angle at the level of the fetlock to simulate normal fetlock positioning with the sole flat on the ground. The forward angle is more effective for most forelimb and hindlimb injuries, when weight bearing should be minimized.
Nonslip tape should be placed on the foot plate after the splint is applied to improve traction on hospital flooring. Nonelastic tape can be placed over this splint to provide additional support.
Extensor Tendon Lacerations
Lacerations or rupture of the extensor tendons, unlike flexor tendons, require a different type of splint. When both extensor tendons are completely disrupted, the horse will knuckle over, potentially injuring the dorsal aspect of the fetlock and further disrupting any associated wound. Therefore, complete dual extensor tendon disruption requires external coaptation to prevent knuckling over at the fetlock. A splint is applied to the dorsal aspect of the forelimb or hindlimb cannon, with the hoof flat on the ground to prevent joint flexion.
Immobilization of Level 2 Injuries
Level 2 orthopedic injuries include the following:
mid- to proximal cannon bone fractures
carpal bone fractures
distal radial fractures
wounds involving the carpus
The goal of level 2 coaptation is to prevent angulation and place the carpal joints in extension.
Level 2 Forelimb Injuries
For level 2 injuries of the forelimb, a moderately thick Robert Jones bandage is applied up to the olecranon, with each layer wrapped separately to prevent slipping. The bandage should be up to 3 times the diameter of the limb when finished so that the entire splint lies flat against the bandage over its length (see forelimb level 2 PVC splint image).
Courtesy of Dr. Amelia Munsterman.
Two orthogonal splints are applied, one lateral and one caudal. Splints should extend from the floor to the point of the olecranon, and the sole of the hoof should be flat on the floor.
Level 2 Hindlimb Injuries
For level 2 hindlimb injuries, as in the forelimb, the bandage should be up to 3 times the diameter of the limb and extend from the floor to the stifle. Two splints are needed. One splint will extend from the floor to the stifle laterally. However, because of interference with the reciprocal apparatus and the angulation of the hock, the caudal splint cannot extend up to the stifle and should stop at the point of the hock.
Immobilization of Level 3 Injuries
Level 3 orthopedic injuries include the following:
mid- to proximal radial fractures
carpal or tarsal instability
tibial fractures
When instability due to fracture or luxation occurs at the carpus, tarsus, radius, or tibia, the flexor muscles of the limb become abductors, resulting in valgus angulation of the limb. The medial aspect of both radius and tibia does not have sufficient muscle mass to help prevent penetration of the skin by fractured bone, and open fractures are common. The goal of external coaptation is to prevent abduction of the limb and further soft tissue injury.
Level 3 Forelimb Injuries
For the forelimb, splint application for level 3 injuries is similar to that for level 2 injuries; however, the lateral splint must extend from the ground to the withers. The caudal splint is the same as the level 2 splint, extending up to the elbow. The lateral splint above the bandage should be well padded to improve fit and prevent skin injury (see forelimb level 3 coaptation image).
Courtesy of Dr. Amelia Munsterman.
Once the horse is standing in the trailer, the splint above the elbow can be padded and secured to the chest with nonelastic tape in a figure-of-eight configuration for further stability, if needed.
Level 3 Hindlimb Injuries
For the hindlimb, the level 3 splint is similar to the level 2 splint; however, the caudal splint is not needed, and the lateral splint should extend to the level of the tuber coxae (see hindlimb level 3 coaptation image). The splint can be a wide wooden board or a contoured metal splint made of electrical conduit pipe. Adequate padding should be placed wherever the splint contacts skin above the bandage. Placing the fetlock in extension can facilitate splint application.
Courtesy of Dr. Amelia Munsterman.
Immobilization of Level 4 Injuries
Level 4 orthopedic injuries include the following:
scapular fractures
humeral fractures
femoral fractures
pelvic fractures
olecranal fractures and radial nerve paralysis (disrupting the passive stay apparatus)
Level 4 Forelimb Injuries
For level 4 forelimb fractures and radial nerve paralysis, a level 2 bandage is applied, and a caudal splint from the ground to the elbow is added to fix the carpus in extension. In cases of nerve injury, continued flexion of the carpus can injure the dorsal aspect of the limb and eventually lead to flexor tendon contracture without coaptation.
Although they do not directly stabilize level 4 fractures, splints prevent tendon contraction and allow the horse to prop the leg, decreasing anxiety.
Level 4 Hindlimb Injuries
External coaptation is not indicated for fractures of the hindlimb at level 4. The joint above and below the fracture cannot be immobilized to allow for fracture stabilization. Bandaging cannot be successfully applied in these proximal injuries. Hematoma formation and soft tissue swelling around the site of injury provide functional immobilization until a diagnosis is made.
If the pelvis is fractured, the need for transportation and further diagnostic testing should be discussed with the owner, because motion during transit can displace fracture fragments and result in fatal hemorrhage.
Guidelines for Safe Transportation of Injured Horses
Before loading an injured horse for transport, proper functioning of the vehicle should be confirmed, the horse stabilized, and the injury immobilized as described above. A low ramp facilitates loading and unloading. The trailer should be brought to the horse, if possible. After loading, the trailer partitions should be placed close to the horse so that the patient can lean on the wall; the partitions can help with balance and decrease the load on the injured leg.
A horse should never be transported loose in a trailer. A sling can be placed under the abdomen to help decrease weight bearing on the limb. Many trailers have standing stalls at an angle (slant-load trailers), which help horses balance during transport. If a straight-load trailer is used, the horse should be loaded facing backward for a forelimb injury and forward for a hindlimb injury to help cushion the injury during sudden stops. The head should be tied loosely, in case the horse falls, and a hay net provided to decrease anxiety.
Frequent stops should be made to check on the status of the horse and provide drinking water. If the horse exhibits marked cardiovascular compromise, IV fluids can be administered while in transit.
If the horse is severely injured and must remain recumbent, it can be pulled onto the trailer with a glide after the limb is stabilized. The horse should be kept sedated during transport to avoid further injury. A padded head protector, hay bales, or a bandage can protect the head from self-trauma, and the down eye should be padded with a towel or blanket. The halter should be padded or removed to decrease the risk of facial nerve paralysis, and lower limb bandages should be applied to the remaining limbs to avoid trauma resulting from paddling. Hobbles could be required to further immobilize a sedated horse.
Foals can be transported in lateral recumbency with the help of restraint by a handler, either in a trailer with the mare or separated from the mare in the vehicle with a handler.
Wounds and Lacerations in Horses
Wounds and lacerations are common in horses and are initially assessed as follows:
All involved structures (synovial cavities, bones, soft tissues) are identified.
Active hemorrhage is controlled.
The need for referral is assessed.
Referral to a surgical facility is recommended in cases of tendon injury, penetration of a synovial structure, extensive degloving injury, severe blood loss, neurological signs, or involvement of the thoracic or abdominal cavity. In addition to wound management, immediate treatment with tetanus prophylaxis, analgesia, and appropriate antimicrobials is indicated. If severe blood loss has occurred, cardiovascular support should be provided before and/or during transportation.
Diagnosis
Evaluation of Damaged Structures
A brief physical examination of a wounded horse should be completed before the primary problem is addressed. If the wound is located on a limb, the presence and extent of lameness should be noted as indicators of potentially more serious injury and the need for coaptation. The followingcharacteristics of the injury should then be evaluated:
location
sources of hemorrhage
penetration of a body cavity
penetration of a synovial structure
tendon injury
Before the wound is assessed, a sterile, water-based lubricant should be applied to the wound bed, the hair around the wound should be clipped, the skin should be aseptically prepared, and the wound should be lavaged with saline solution. Wounds over joints, tendon sheaths, or tendons (particularly flexor tendons); puncture wounds; and wounds that expose or penetrate bone should be explored thoroughly for injury to important underlying structures.
Hemorrhage might need to be controlled before further wound assessment is possible. Pressure bandages can be applied, and if the bleeding vessel can be located, it should be temporarily clamped or ligated. Certain wound configurations (eg, an inverted V configuration, crushing injuries with extensive bruising) can substantially damage blood supply to the skin and subcutaneous tissues, resulting in sloughing.
Wounds over the chest or abdomen can lacerate organs or large vessels. With thoracic wounds, development of an open or closed pneumothorax can lead to severe respiratory distress. Any horse with chest trauma and dyspnea should have open wounds sealed with plastic, airtight bandages and be evaluated for pneumothorax or pneumomediastinum.
Assessment of Synovial Involvement
In horses with wounds or lacerations, the potential involvement of a synovial structure should be determined immediately. The horse should be restrained and sedated as needed for the procedure.
A site of entry into the joint or tendon sheath remote from the wound is chosen, the hair clipped, and the skin aseptically prepared. Saline solution or a balanced electrolyte solution is injected aseptically into the synovial compartment. The amount needed to achieve distention and back pressure can vary from a few milliliters, in the case of the distal tarsal joints, to > 100 mL for the femoropatellar joint.
All compartments of the joint suspected to be involved should be assessed. Synovial structure involvement is confirmed if the injected solution leaks from the wound. If communication is not noted, the solution is aspirated from the joint, and the structure is injected with a prophylactic dose of antimicrobial (eg, amikacin).
In chronic wounds or injuries caused by a puncture, communication with the synovial cavity might have sealed, preventing leakage of injected fluid from the wound site. Therefore, alternative methods for assessing synovial involvement include infusion of radiopaque contrast solution, or placement of a sterile probe aseptically into the wound. More advanced procedures to assess synovial involvement include arthroscopy and advanced imaging, such as CT or MRI.
Over the next 3–5 days, horses with wounds over synovial structures should be reevaluated for increased lameness, heat, or effusion, which could be evidence of an insidious infection. If there is appreciable edema, swelling, or skin trauma over all points of entry, the synovial structure should not be tapped, to avoid the possibility of iatrogenic infection. In these cases, radiographic assessment and close monitoring or direct probing of the wound with a sterile metal instrument could be diagnostic.
Evaluation of Tendon Injury
Extensor tendon injury of the distal limbs in horses results in an inability to appropriately place the hoof on the ground and knuckling over. These clinical signs suggest involvement of both extensor tendons in the proximal metacarpus or metatarsus or of the common digital extensor tendon more distally.
Flexor tendon injuries result in hyperextension of the fetlock (superficial digital flexor), lifting of the toe (deep digital flexor), or complete dropping of the fetlock to the ground (severed or ruptured suspensory ligament). For these signs to be evident, the horse must bear weight on the limb at least transiently; however, it is not advised to force the horse to bear weight for a diagnosis, because the original injury could worsen.
In horses with complete suspensory ligament breakdown, often combined with proximal sesamoid fractures, stretching the digital vessels can lead to thrombosis and avascular injury, as well as to necrosis of the distal limb. It is important to support the fetlock and prevent weight bearing until the limb is stabilized in a flexed position.
Treatment
The following steps should be taken to treat wounds in horses:
Clip hair and prepare the site.
Determine the extent and severity of the injury
Debride and, in some cases, close the wound.
Bandage the wound/injury.
Administer local and/or systemic antimicrobials.
Provide appropriate pain management.
Administer tetanus prophylaxis.
The goals of initial wound care are to decontaminate the wound as much as possible and prevent further contamination. After the hair is clipped and the intact skin is prepared sterilely, injured tissue is lavaged with sterile saline solution and cleaned via sharp debridement of gross contamination.
The wound should be dressed with a sterile, nonadherent bandage and a support wrap or padded bandage. Immobilization of the limb will be needed if there is injury to a supporting structure (bone, tendon) or appreciable instability (luxation).
Definitive treatment and wound closure can be provided if the wound is fresh and clean enough for primary closure; however, caution should be exercised in the closure of deep, dissecting wounds because they usually cannot be completely decontaminated. Second-intention healing might be required for contaminated wounds or wounds with extensive tissue loss.
Pneumothorax
A penetrating chest wound can lead to pneumothorax and respiratory distress. If pneumothorax is not treated, potentially fatal pneumomediastinum can result. Examination reveals a restrictive pattern of respiration. Auscultation of the thorax reveals a lack of breath sounds in the dorsal lung fields. Because the mediastinum in horses is incomplete, a unilateral chest wound can lead to bilateral pneumothorax.
An open pneumothorax is managed by providing a temporary seal over the chest wound. The wound is cleansed and bandaged with a layer of airtight plastic wrap and sealed with elastic adhesive tape (see thoracic injury image). The chest is then evacuated by inserting a 14-gauge catheter, using aseptic technique, in the dorsal aspect of the 12th intercostal space (ICS). Aspiration can be facilitated via a three-way stopcock and 60-mL syringe or by negative suction.
Courtesy of Dr. Amelia Munsterman.
A closed pneumothorax might require an indwelling chest tube and Heimlich valve until the cause is resolved.
Hemothorax
Hemothorax is a possible complication of a penetrating chest wound and can lead to respiratory distress similar to that resulting from pneumothorax. Auscultation of the thorax reveals a lack of breath sounds in the ventral lung fields, as well as muffled heart sounds. If dyspnea is noted, the hemothorax should be drained; however, if the horse is breathing normally, the chest should not be tapped, because blood will gradually reabsorb on its own.
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To evacuate the chest, a 14-gauge catheter or thoracic trocar is aseptically placed in the ventral aspect of the 6th-8th ICS. Ultrasonographic examination helps guide placement and prevent accidental penetration of vital structures. Aspiration can be facilitated via a three-way stopcock and 60-mL syringe or provided by passive drainage with a one-way Heimlich valve.
Complications of thoracic drainage can include pleuritis due to introduction of bacteria, continued hemorrhage, and hypovolemic shock if the fluid in the third space is removed too quickly. Conservative fluid therapy should be provided for cardiovascular support, and a transfusion might be needed.
Penetrating Abdominal Wounds
Penetration of the abdominal cavity in horses is a serious and potentially fatal injury (see abdominal wound image) that can lead to hemorrhage, penetration of an abdominal organ, or development of peritonitis. If a penetrating wound is suspected, it should be clipped of hair, aseptically prepared, cleansed with saline solution and low-pressure lavage, explored for the presence of foreign bodies, and debrided.
Courtesy of Dr. Amelia Munsterman.
The following techniques can provide additional diagnostic information:
Transabdominal ultrasonography can reveal free fluid in the peritoneal space; however, subcutaneous air from the laceration might limit visibility.
Abdominocentesis can detect contamination that indicates a ruptured viscus, as well as internal hemorrhage. However, abdominocentesis might not be diagnostic initially, because indicators of peritonitis (eg, increased total protein concentration, leukocytes, bacteria, changes in lactate and glucose concentrations) can take several hours to develop.
Radiography can be useful in foals or American Miniature horses.
An exploratory laparotomy might be needed for comprehensive assessment of internal injuries.
Uncomplicated wounds should be bandaged, and treatment with broad-spectrum systemic antimicrobials and pain management should be initiated. If the wound is large or the abdominal musculature is involved, the abdomen can be supported with a compressive bandage.
Neurological Trauma in Horses
Neurological trauma can result from primary injury (eg, contusion, laceration, fracture, hemorrhage) or secondary to traumatic insult (eg, subsequent edema, reperfusion injury, secondary necrosis). Treatments for neurological trauma are designed to minimize secondary CNS damage.
Clinical Signs
Traumatic head injuries in horses can result from direct impact and contrecoup injuries. A common way that horses sustain neurological injury is by rearing over backward and landing on the poll, sometimes avulsing the ventral cervical muscles that attach to the skull.
Injuries associated with this type of fall include basisphenoid fractures, with avulsion of the longus capitis and/or rectus capitis ventralis muscles from the base of the skull. Rupture occurs at the insertion of the muscle dorsal to the guttural pouch. Hemorrhage into the retropharyngeal space can cause asphyxia and death.
Retroflexion of the endoscope on endoscopic examination reveals swelling and hemorrhage in the most rostral and medial aspects of the guttural pouch. Notable neurological deficits, including acute blindness secondary to damage to the optic nerve, often accompany such basisphenoid fractures.
Lateral radiography can show an avulsion fracture of the basisphenoid bone overlying the guttural pouch region. CT scan is useful when radiographic findings are inconclusive.
Diagnosis
Radiographic or CT evaluation
Upper airway endoscopic assessment
Necropsy
Diagnosis of neurological injuries in horses is based on assessment of cranial nerves, static examination, and, if safe, evaluation in hand.
Radiography and CT are used to identify skull fractures, avulsion fractures, and soft tissue opacities in the guttural pouch (consistent with hematomas from rupture of the ventral straight muscles). See radiographic and CT images.
Courtesy of Dr. Bonnie R. Rush.
Courtesy of Dr. Amelia Munsterman.
Endoscopy can show hemorrhage from the guttural pouch originating from the base of the stylohyoid bone or medial wall of the guttural pouch (see endoscopic image). Hematomas in the guttural pouch septum where the ventral straight muscles lie can also be shown, and hemorrhage caused by fractures draining from the ethmoid turbinates can be evident.
Courtesy of Dr. Amelia Munsterman.
Treatment
Supportive care (fluid therapy, corneal lubrication)
Anti-inflammatories (NSAIDS, corticosteroids)
Anticonvulsants
Neuroprotectants
Treatment of head injuries is mainly supportive to decrease secondary CNS damage. Horses with head injuries can be severely ataxic and should be handled and moved with extreme caution. If the horse is recumbent, administration of short-term general anesthesia is best to transport the horse to a referral facility for further evaluation and supportive care.
Because they can decrease cerebral perfusion pressure, opioids should be avoided for sedation of horses with head trauma. The horse should be administered IV fluids to maintain normal blood pressure and lower the risk of cerebral ischemia. Diuretics are contraindicated.
If hypoventilation develops, the horse should be intubated and ventilation assistance provided to prevent hypercapnia.
If the blood-brain barrier has been breached by a fracture, broad-spectrum systemic antimicrobials should be started. Anti-inflammatory medications are indicated, and seizures should be managed with diazepam (0.02–0.4 mg/kg, IV) or midazolam (0.02–0.4 mg/kg, IV) for short-term control, or with phenobarbital (5–15 mg/kg, IV, slowly) for horses refractory to benzodiazepines.
Although corticosteroids are controversial for traumatic brain injury in human medicine, they can be indicated in the acute phase of neurological injury in horses (eg, dexamethasone, 40–100 mg, IV). Dimethyl sulfoxide, or DMSO (1 g/kg, IV, administered in 5-L balanced electrolyte solution every 12 hours) has also been used to minimize secondary edema and decrease intracranial pressure.
More effective for treatment and prevention of cerebral edema is 20% mannitol (1 g/kg, IV, every 6–12 hours) or hypertonic saline solution (7.5% NaCl; 4–6 mL/kg, IV, every 6–12 hours). Magnesium (0.05 mg/kg, IV over 30 minutes) has also been proposed as a therapeutic agent to decrease cerebral ischemia.
The prognosis for full recovery from neurological injury varies with the severity and progression of clinical signs. Persistent neurological signs, recurrent hemorrhage, and basilar skull fractures worsen the prognosis.
Key Points
In horses with suspected fracture, splints should be placed before the horse is moved and before radiographic imaging to prevent further injury to bone or soft tissues.
When placing a splint, the entire splint must lie flat against the bandage so that the splint applies even pressure across the fractured bone. Additional padding might be needed to ensure correct splint placement on the limb.
Lacerations should be thoroughly evaluated for involvement of synovial structures.
Ultrasonography, transrectal palpation, and abdominocentesis can be helpful for evaluating abdominal wounds.
Thoracic wounds can cause pneumothorax, hemothorax, or pneumomediastinum, which could require thoracostomy tube placement. Wounds should be sealed and investigated with advanced imaging techniques.
Head trauma in horses is not uncommon and can result in neurological injury; basisphenoid fracture or longus capitis avulsion can occur if the horse rears over and strikes its poll.
For More Information
Morgan JM, Galuppo LD. Fracture stabilization and management in the field. Vet Clin North Am Equine Pract. 2021;37(2):293-309.
Freeman SL, Ashton NM, Elce YA, Hammond A, Hollis AR, Quinn G. BEVA primary care clinical guidelines: wound management in the horse. Equine Vet J. 2021;53(1):18-29.
Also see pet owner content regarding emergency care for horses.
