LIFE AFTER LAMINITIS
By Thomas B. Massie, Jr., DVM
Laminitis (founder) in the horse can be a devastating disease process and it can take many forms. In some cases, the horse is mildly affected and recovers without significant problems. Others, the condition can be so severe that pain cannot be controlled and the support structure of the foot fails completely. In these cases, the horse will at least be lost for athletic use and in some, humane euthanasia can be the only option. Why the huge variation in case response and what factors can we control to affect a more positive outcome?
In order to answer these important questions, we first must be sure we understand the anatomy and mechanics of the equine foot. Equine Laminitis is a complex syndrome that regardless of cause results in decreased blood flow to the foot. In particular, blood flow to the laminae, the part of the foot that maintains connection of the hoof to the coffin bone, is critical. The laminae are metabolically active structures and they are extremely intolerant of a cessation of nutrient delivery. The duration and completeness of the decreased blood flow often determines the severity of the resultant laminitis. The longer and more completely blood flow is decreased to the foot, a greater severity of the resultant laminitis can be expected. Without needed blood flow and oxygen delivery to the laminae, the cells that make up this vital structure begin to die and become weak. As they weaken, the coffin bone begins to tear away from the hoof wall and severe pain results. If we can quickly and efficiently improve blood flow and provide some support to the coffin bone, we can radically improve clinical outcomes. Improved blood flow can also speed delivery of needed nutrients and anti-inflammatory drugs to the affected area. If everything goes well, these horses will be significantly more comfortable within 2-3 days of the initiation of treatment. Unfortunately, these horses will always be more likely than normal horses to suffer from laminitis in the future. This is likely due to increased presence of scar tissue in the laminae. This scar tissue is not as strong as the normal tissue and blood flow to the scar is less complete and irregular.
The bottom line is that the most common reason for a horse to suffer from laminitis is that they have had previous bouts of laminitis. These flare ups result in greater deposition of scar tissue and a greater likelihood of laminitis. So, what can we do to prevent successive bouts of laminitis? What can we do in the healing phase to improve the production of high quality hoof that can support exercise? What factors can we study to determine if an individual horse will be able to return to work?
What can we do to prevent successive bouts of laminitis?
In most cases, controlling diet, exercise, and providing appropriate hoof care will go a long way to prevent further painful episodes. Maintaining sound hoof mechanics and attention to subtle changes will greatly help to maximize blood flow to the feet. The longer we can go between painful episodes, the stronger the laminae will become. If metabolic disease (i.e. Diabetes, Cushings Disease, Metabolic Syndrome, etc.) is present in the patient, it should be carefully managed. In general, successful management of the horse which has suffered from laminitis will require great attention to detail and consistant management. If this can be done, many of these horses will again perform at a high level.
What can we do in the healing phase to improve the production of high quality hoof that can support exercise?
The single most important item that should be employed during the healing phase is exercise restriction. Following that, assuring proper hoof mechanics, coffin bone support, nutrition, medication, and consistency are all critical. For us, 3-6 weeks of stall rest can seem like an eternity, but for the healing hoof, it is nothing. The less times the horse cycles this foot through a walking motion, the better. This is magnified if the horse is walking on uneven ground.
Proper hoof mechanics are a team effort in my opinion. The work of the owner, farrier, and veterinarian are equally important. The farrier has a difficult time trimming the laminitic foot to obtain the greatest mechanical advantage to assure proper healing because the hoof no longer appears normal. The landmarks used to guide trimming are often either invalid or inappropriate. Radiographs of these feet are a tremendous help as they allow us to trim the foot aggressively and make decisions based on the bony anatomy. This, after all, is the goal because the hoof that we see will forever be changed as will its connection to the coffin bone. We must trim and shoe the horse to assure proper coffin bone support and angualtion if we expect to heal these feet efficiently. In most cases, I recommend taking radiographs 2-3 weeks following the initial insult to assess the damage done. Then, after appropriate trimming, we will continue to follow the horse through the next few months of healing. Often, we meet with the farrier and work together. Digital Radiography allows us to obtain stall side images and make decisions more rapidly than ever before. In most horses, a return to some level athletic soundness can be expected within 12 months and often within 6-8 months.
Nutrition is critical in these stall bound horses that eat only preserved feed. In particular, micromineral nutrition becomes important. Medications are also employed to do everything from improving blood flow to decreasing scar tissue formation. All will decrease pain and improve the likelihood of normal life following severe laminitis.
What factors can we study to determine if an individual horse will be able to return to work?
There are many studies on this subject and predictions are thus made. The literature would indicate that for horses whose coffin bone rotates less than 6 degrees, they will have an excellent chance of returning to athletic work. If between 6 and 12 degrees, many will return to work, but often at a lower level. For those whose coffin bone rotates greater than 12 degrees, it will be difficult for them to return to soundness. In general, I support these axioms, but I have seen horses from all categories return to soundness. I have also seen horses from all categories fail to even become pasture sound.
Attention to detail while healing these horses is paramount. We must listen to the horse and carefully evaluate all decisions in the early healing phases. I feel it is also important to periodically radiograph these horses over the first two years following insult to assure proper mechanics are maintained. Teamwork can help save these horses and assure that they and their owners can enjoy many more days.