The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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A24 TheHorse.com/AAEP2017 AAEP Wrap-Up THE HORSE March 2018 YOUR GUIDE TO THE 2017 AAEP CONVENTION Finally, he said, improved regional pain medications, allowing delivery straight to the area of concern, could help reduce affected horses' pain. The research into SLL is ongoing, and van Eps and colleagues are working to find new ways to combat and prevent it. "We are evaluating new means of improving foot perfusion using devices designed to dynamically manipulate the load on the supporting limb," he said. "We are also utilizing the robotic imaging facilities at New Bolton Center to better understand blood perfusion to the foot under load." Managing Two Common Laminitis Complications Two of the most common laminitis complications veterinarians face are inju- ries to the subsolar tissues (the soft tissue located between the coffin bone and the hard/keratinized sole, in front of the frog) and sole, such as coffin bone penetration and subsolar abscesses. James Belknap, DVM, PhD, Dipl. ACVS, a professor of equine surgery at The Ohio State University College of Veterinary Medicine, in Columbus, gave veterinarians tips on how to evaluate and manage these scenarios. Horses that develop complications typically exhibit more severe lameness (usually in one limb) and, possibly, an increased heart rate and increased recumbency, he said. "The question is whether the pain is coming from the sole or the lamellae." To find out, he said veterinarians must examine the hoof, sole, and frog and determine whether the horse is painful in response to solar pressure (indicative of sole pain). Radiographs—dorsal-palmar (front to back), lateral, and solar margin views, specifically—can also reveal valu- able information about what's happening inside the hoof. Nerve blocks can help the veterinarian localize pain to the hoof (and numb the hoof for later treatment); however, Belknap said they won't neces- sarily help differentiate solar from lamel- lar pain, because the same nerve block anesthetizes both structures. After thoroughly evaluating complica- tions, veterinarians can develop treatment plans. Subsolar abscesses These painful infections can be bad news for laminitic horses. Belknap said one major concern is exacerbating laminar injury in the opposite foot if the horse offloads weight from the abscessed hoof (what's seen with SLL). He said it is much more common for laminitis-related subsolar abscesses to be "underrun abscesses" (involving a large portion of the sole). Therefore, it's impor- tant for the veterinarian to determine the extent of the sole involved and "establish Evaluating Extremely Painful Horses With Laminitis Laminitis is a debilitating disease. Affected horses that are under particular duress must be evaluated carefully to avoid fur- ther pain and lamellar damage. James Belknap, DVM, PhD, Dipl. ACVS, a professor of equine sur- gery at The Ohio State University College of Veterinary Medicine, in Columbus, reviewed how to evalu- ate these patients. As with any veterinary exam, a thorough history is important. Key factors include when the episode began (specifically regarding sea- son and forage availability), any dietary changes, previous lame- ness issues, and recent infections that could lead to sepsis (infec- tion of an organ that results in a systemic inflammatory response). The veterinarian should also ex- amine the hoof and surrounding structures for signs of laminitis, such as coronary band separa- tion from the hoof wall or solar surface abnormalities. "The heart rate is extremely important to obtain initially," Belknap said. "In my view, the heart rate (if not increased due to sepsis) is the most valuable physical parameter regarding assessment of the horse's duress. Whereas heart rates in the range of 45 to 55 beats per minute are common with moderate pain in laminitis cases, heart rates in the 60s—and especially those in the 70s and 80s—are of great con- cern not only regarding humane grounds but also prognosis." If the horse can walk, the veterinarian might perform a lameness exam that includes walking in a straight line and turning figure-eights on hard and soft surfaces. If endocrinopathic laminitis (the most common form that's often associated with equine metabolic syndrome and pituitary pars intermedia dysfunction) is the key concern, the veterinarian might have the horse jog on a soft surface. Regardless of the type of laminitis, the veterinarian must determine how much, if any, coffin bone displacement has occurred. For this reason hoof radiographs (X rays) are critical. Belknap said administering short-lasting nerve blocks in the front feet can help rapidly reduce the horse's pain and allow veteri- narians to get better radiographs; they're able to manipulate the horse's feet better without making him more painful, which can lead to improved image quality. Blocking the front feet also allows veterinarians to assess any hind- limb involvement. He cautioned that if horses can't feel their hooves, they could move around too much and cause additional lamellar damage. As such, he recommended protecting the hooves (e.g., with padded boots) to reduce the likelihood of further damage and restraining horses until the nerve blocks wear off. Belknap said to avoid holding one hoof in the air for prolonged periods, as this could lead to further lamellar damage in the opposite limb. He also advised practitioners to, in most cases, remove the horse's shoes during the exam and supply adequate hoof support and padding. Belknap said it can be difficult to determine if and how much the coffin bone has moved if baseline radiographs aren't available. Therefore, he recommended tak- ing serial radiographs to measure ongoing displacement. In most cases, he said, veterinarians won't need to collect additional types of imaging. The exception might be if a horse is extremely painful but has no evi- dence of laminitis on radiographs. In these cases veterinarians might have a better chance of seeing lamellar separation on MRI. From there, the practitioner can formulate a treatment plan, as well as a prognosis.—Erica Larson