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Dr. Christine King Ph: (336) 608.8552 e-mail: king(at)animavet.com | ||||
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"Diagnosing Lameness: a tool or two you might not have considered." Few things are more frustrating than finding your horse lame for no obvious reason. ... [Full-text article by Dr. Christine King] Please note that this article is copyrighted, so if you want to reuse it in any sort of publication (web site, printed media, etc.), then please contact me for permission and guidelines for reuse. Enjoy! ****************************************** | |||||
Diagnosing Lameness a tool or two you might not have considered Dr. Christine King Few things are more frustrating than finding your horse lame for no obvious reason. No recent injury you’re aware of; no wounds; maybe a little swelling somewhere, maybe not; maybe a little heat, maybe not, and if there is heat, it’s so spread out that all it really tells you is the general area of concern—maybe. Sometimes that heat is a red herring and the problem lies elsewhere. These cases have challenged veterinarians for ages as well. Even with all the diagnostic tools we have today, it can be very difficult to find the source of the lameness in a body other than your own, in a patient who can’t tell you directly where it hurts. So, the diagnostic phase of dealing with lameness can sometimes be a bit like a Sherlock Holmes mystery. In fact, that’s not a bad analogy to play with here, as the fictional Holmes practiced his detective methods in an era before all the sophisticated tools and techniques of today were available. Although he was a made-up character, his methods and challenges were not a lot different from those of the veterinarians and blacksmiths of old, who had to rely on their five senses, their experience, a couple of very simple tools, and that mysterious but universal sixth sense: intuition or “gut feeling.” That rudimentary set of living tools is still essential today in diagnosing lameness. When we ignore or downplay these fundamentals and go straight to the nerve blocks, the x-ray machine, or the even fancier equipment, we usually miss something that is essential in understanding not just what went wrong, but why. Without understanding why the system broke down as it did, the treatment plan is likely to be incomplete and the prevention plan for avoiding a repeat performance is almost certain to fail. I’ll get to the examination process in a moment. First I want to talk about the importance of using one’s sixth sense in problem-solving, such as figuring out where and why a horse is lame. The really good lameness vets seem to use this sense spontaneously, almost always without talking about it, and probably in many cases without even being fully aware that they’re using it. It’s more than just experience, which is largely a numbers game, an informal type of statistical database mining—e.g. most Quarter Horses I’ve seen have had x; or she’s a Thoroughbred, so it’s probably y. Intuition is the spontaneous knowing that psychologists and brain researchers consider a working feature of the right side of the brain. It’s organic, and it’s universal; we all have it. The best lameness vet I’ve ever worked with was a brilliant young equine surgeon who had a knack for knowing just where to look and what to look for in a lame horse. “Take more films of the stifle; she has a bone cyst in there.” We objected; we’d already wasted time x-raying the stifle and found nothing. But still he had us go back, adjust the angle and settings on the x-ray machine, and repeat the films until we found it. Sure enough, there it was, plain as day on the third or fourth set of films. He was almost never wrong, and the few times he was, he berated himself loudly for not doing what he knew he should. “I knew I should have looked in the foot! Why on earth did I let myself get talked into spending all that time on the hip?!” The horse, a valuable young stallion, had been referred to us for x-rays of the hip. Turns out, he had a coffin bone fracture—and a perfectly normal hip. But by the same token, I’ve lost count of the number of times I’ve been asked to examine a lame horse who had been diagnosed as having one thing by an animal communicator or some other type of professional intuitive, only to find that the horse had something else instead or as well. I use intuitive evaluation routinely myself, but I also use my basic five senses, my knowledge and experience, and conventional diagnostics when they’re warranted. The point is not how great am I, but that it’s important for us to use all of our senses and pull from all of the available tools to arrive at the answer. To rely on intuition instead of rational thinking is just as unbalanced as the opposite, using only rational thinking. We have both, and we’re wise to use both, even if we’re more used to relying on one than the other. That brings me to a comment I want to make about the prevailing paradigm that currently has veterinary medicine in a stranglehold: “evidence-based medicine,” or EBM for short. It is the very antithesis of intuitive thinking, and in fact does not consider our sixth sense a legitimate source of evidence at all. Those who use or even mention intuition are disparaged as being “unscientific,” even though some of the greatest scientific discoveries were made through an intuitive leap, a classic “Eureka!” moment. I once heard EBM described by a much better acronym: SAD, for Statistically Arrived Diagnosis. Yep; that’s about the size of it. Rigidly adhering to only what has been published in the scientific literature and only what can be measured is a rather sad way of relating to the magic and mystery of living things. It’s an uninspired and uninspiring way of operating—and, no surprise, its answers are very often incomplete. But enough philosophizing. Back to our lame horse. When you look at him, what do you notice about the way he stands and moves? What part of himself does he seem to be protecting from load and perhaps from further injury? Imagine yourself in his body... occupy the whole body and then survey the entire system; if necessary, imagine walking or trotting in that body. What do you feel? Where does it hurt? What are you trying to protect? And how did this happen? In most cases, lameness is about protecting a painful area from some or all of its normal weight-bearing load. Some problems are more mechanical, primarily involving functional restriction with little or no pain, but for the most part when we’re observing a lameness, we’re observing a protective response to pain. So, developing a practical empathy for the patient—a felt sense that doesn’t let you get caught up in the pathos of the situation—can be very useful in understanding what has happened. I’ve found this simple mental exercise of imagining I’m the horse tremendously useful in narrowing down the site(s) of the lameness to a specific area (or areas) when the cause of the lameness isn’t immediately obvious. I then follow it up with a careful examination of the whole horse using the rest of my senses and any diagnostic procedures that may be warranted. If you’ve been around horses for more than a couple of days, you’ll probably have watched a veterinarian examine a horse for lameness, so I won’t bore you with the process here. Suffice it to say that diagnosing an obscure lameness is basically a process of elimination. By conducting an orderly examination of all the accessible structures in the limbs, and in the neck and back as well, by watching the horse in motion, and using nerve or joint blocks as needed, the problem is eventually identified, or at least narrowed down to a specific area of the body and a short list of possibilities. Then one or more of the available diagnostic imaging procedures (see the table at the bottom of the page) may be used to arrive at a final diagnosis. It’s Sherlock Holmes type stuff: collect clues, form a working hypothesis, test it out, repeat until the culprit is found. But the truth is, we don’t always reach a definite conclusion (diagnosis) with these obscure lameness cases. In fact, in this current economic climate it’s become increasingly common to do a partial lameness exam, narrow the field of possibilities as best we can, and then take the “diagnosis by treatment” approach, where we work backwards to arrive at a diagnosis, starting with how the horse responded to treatment. This type of diagnostic approach is sometimes jokingly called a SWAG: a scientific wild-ass guess. Using our best judgment, based on our training, experience, and the examination up to that point, we start a treatment plan we hope will be effective and then reevaluate the horse in a few days or weeks, depending on the situation. It’s also OK with a mild lameness to wait and see for a day or two before calling the vet. Some problems will get better on their own in a few days. After all, bodies are designed to be self-maintaining and self-repairing. But the wait-and-see approach is unfair if the horse is quite lame, and beyond a few days if the horse is mildly lame. It may also be counterproductive in the long run, and false economy even with a mild lameness, if you need the horse to be sound for riding sooner rather than later. The sooner you get veterinary attention and start an appropriate treatment plan, the better. If you are opting for a brief wait-and-see, then use that time to start gathering clues yourself, even if the lameness is improving. Knowing what and why will help you prevent a repeat. Some of this detective work you can do yourself, as it requires no special tools; just good powers of observation, attention to detail, and a practical empathy which helps point you toward where it hurts and why. There are few things more frustrating to a veterinarian than being called out to examine a lame horse only after the farrier, the chiropractor, the animal communicator, and the local “healer” have all had a go and weeks have now gone by. But it also makes me sad to find a caring horse owner who so doubts her own ability to know what’s wrong with her horse and what’s needed that she rushes from one “expert” to the next, searching for answers that just might be available directly to her if only she’d stop, get quiet, and look for herself.
Diagnostic imaging procedures used to identify Procedure - used most often to identify... Thermography - areas of unusual body surface temperature; an unexpected increase or decrease in temperature suggests an increase or decrease in blood flow or tissue activity in that area Radiography (x-ray) - bone defects, such as fractures, bone cysts, bone spurs, rotation or sinking of the coffin bone in laminitis, and the bony changes of osteoarthritis (OA); limited use for identifying soft tissue or cartilage defects, although narrowing of a joint space hints at cartilage loss Ultrasonography (ultrasound) - soft tissue defects, such as tendon and ligament injuries, and changes in the surface of bone, such as fractures or OA in areas that are difficult to x-ray (e.g. the pelvis and spine); the ultrasound waves used in these machines cannot penetrate bone, but they can provide a detailed image of the bone’s outer surface; may also be used to examine joint cartilage and other structures within a joint, although only part of the joint may be accessible with ultrasound Nuclear scintigraphy (bone scan) - areas of unusual bone activity when x-ray was unhelpful; subtle stress fractures, early OA, and bone/joint problems above the elbow or stifle are common uses of scintigraphy; whole-body scanning is sometimes used when the lameness cannot be narrowed down to a particular area; with proper planning, soft tissue and blood flow abnormalities may also be identified with scintigraphy Magnetic resonance imaging (MRI) - soft tissue and cartilage defects; MRI provides exceptional detail of the soft tissues (sometimes too much) Computed tomography (CT) - almost all of the anatomical structures visible to the naked eye in the area of interest, including bone, soft tissues, blood vessels, and nerves; the software can be used to generate either cross-sectional slices or 3D surface images of the structures of interest Arthroscopy (scoping) - bone, soft tissue, and cartilage defects within a joint, and to repair or remove the damaged tissue if possible; it’s included here because sometimes arthroscopy doubles as diagnosis and treatment
Copyright 2011 Christine M. King. All rights reserved. First published in Trail Blazer, October 2011. | |||||
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