USDF Convention: Veterinary Witchcraft and Wizardry

Veterinary Witchcraft and Wizardry
Tracy Turner, DVM

USDF Convention
December 5, 2003

In the absence of a diagnosis, medicine is POISON, surgery is TRAUMA and therapy is WITCHCRAFT.

The WIZARDRY is in the IMAGING.

Imaging can be divided into anatomic methods and physiologic methods. Anatomic methods (like xrays, ultrasound, CT and MRI) require a structural change in order to pick up an abnormality. They tell you WHAT HAS HAPPENED not what is happening. Physiologic methods (like bone scans, thermography, etc.) are based on blood flow or metabolism and pick up changes in function. They tell you WHAT IS HAPPENING and pick up changes in function, often before structural changes have occurred. Combining the two methods offers the greatest opportunity for a definitive diagnosis. Note that anatomic methods can’t tell you whether or not a finding is an ongoing problem, or give information about viability.

XRAYS are a 2-dimensional representation of a 3-dimensional object. They assess bony change. They are HISTORICAL documents: they tell you what has happened already but cannot give you information regarding the body’s response except by inference.

Not all xrays are created equal
XRAYS expose film.
- Old fashioned film
- CR: xrays expose plate, plate then read by computer
- DR: xrays expose computer’s sensor instantly. This provides the most information, because the computer is able to capture 5000 shades of gray, allowing resolution that veterinarians had previously only dreamed about.

Ultrasound is useful for soft-tissue evaluation.
CT provides high-resolution bone detail.
MRI is good for soft tissue detail, bone detail and edema. It is only just now becoming available for use with horses.

Scintigraphy (Bone Scans): uptake is proportional to the metabolic activity of the bone. More uptake is seen in areas with increased metabolism, and less uptake in areas with loss of blood supply. Causes of increased metabolism include injury, stress and cancer (cancer is rare in horses).

Thermography: Heat is emitted in the form of infrared radiation. Thermography gives us information about the local circulation, the amount of blood flow and the local metabolism.

The readout from a Thermogram is a pictorial representation of the surface temperature of an object, and when combined with a careful clinical exam, it can be useful for:

Picking up previously undetected physical injuries. Dr. Turner told us that in a study they did with racehorses, they were able to pick up injuries 2 weeks earlier than clinical exam (they did thermography on all of the horses, noted the results, did not share with track vets; track vets shared with them if/when race horse was pulled for injury) based on thermography. He suggested it might be useful as a training tool for early detection of subtle strains, allowing us to intervene with ice/modifications so that we can continue work without interruptions due to injury. Small thermography machines are within the price range of large/serious training barns).
Prepurchase examinations: can separate historical changes from inflammatory changes, providing additional information for interpreting flexion and radiographic findings. (Not all positives are significant; the absence of inflammation would be a reassuring finding).
Saddle fitting: can determine if friction exists, and guide adjustments.
Diagnostics: Often the best tool for screening for muscular and ligamentous injuries, which can then further be characterized with other modalities. Examples:
- SI injuries are often most easily identified with thermography. Prior to thermography, they were often misdiagnosed as back pain, poor saddle fit, etc. They can be quickly screened for with thermography, and will show up as a cold spot because the horse will splint (not move) the injured area. If a suspicious area is seen on thermography, it can be further evaluated with ultrasound.
- Dorsal Spinous Process Injury can also be identified with thermography, and will show up as a hot spot. Xrays can be used to characterized at the site once it is localized.
Dr. Turner likes to think of Thermography as a sentinel tool to locate pathologic processes, and to indicate where further diagnostic tests should be performed. He also finds it helpful to determine which horses need bone scans.

The biggest enemy of the elite athlete is OSTEOARTHRITIS.

Overworked joints are subject to trauma. Neutrophils go in to clean up cell damage (think of them as the “Marines”) and release enzymes, but also cause “collateral damage” with inflammatory mediators, resulting in cartilage damage and pain.

What do we have in our arsenal?

Non-steroidals (Bute). These reduce inflammation. The problem with these is that they also slow the synthesis of glycosaminoglycans (so that the body can’t make new cartilage and repair itself as easily), and they can cause gastric ulceration.
Corticosteriods. These are the most potent anti-inflammatories we have. They also stabilize cell membranes and increase synnovial viscosity. The problem is that they decrease local immunity, increasing the risk of infection, they decrease protein and proteoglycan syntheses, and they cause thinning, fibrillation and fissuring of the articular cartilage with multiple uses—making the joint problem worse over time. Another problem, of little clinical significance, is that they cause metastatic calcification of ligaments and tissues.
Hyaluronic Acid. This binds proteoglycans, keeping them from leaking out, and binds to irritating proteoglycans in the synnovial fluid, as well as stabilizing cell membranes—so they are very useful in treating acute inflammation. They can be given both intravenously and intra-articularly; the IV route is easier. There are well-established treatment protocols for acute flares; prevention protocols are less clear.
Glycosaminoglycans. These compounds inhibit catabolic lysosomal enzymes, stimulate hyaluronic synthesis, and decrease inflammation. They also bind to naked cartilage and stimulate chondrocyte metabolism. They can be given intra-articularly, intramuscularly, and orally. Adequan is the best studied, and is considered the gold standard. Therapeutic protocols are well established, with benefits well documented. Prevention protocols are not well established. Only 2 products have done paid for clinical trials: Cortiflex and Cosequin. Note that “generics” and “Nutriceuticals” do not have to have in the bottle exactly what it says on the label—these products are not regulated by the FDA like in the same manner that human pharmaceuticals are, so buyer beware. There may be 2 or 3 times the label amount in some bottles, and none at all in others. Some companies, like Cosequin and Cortiflex, have opened the doors to their manufacturing plants and stood behind their products and their claims—they have made the manufacture and labeling transparent. Not all manufacturers have done so. The most important component in joint nutriceuticals in glucosamine. Does it work in oral form? Can it be absorbed adequately through the digestive tract in a form that is still usable to the cartilage? We don’t know, but Dr. Turner said that all of his horses are on it.

Goals of Rehabilitation: promote healing through stimulation of normal physiological responses. THERE ARE NO MAGIC BULLETS.

Equine Sports Medicine has a number of modalities available, some traditional and some not-so-traditional.

Acupuncture: There are a variety of theories as to HOW it works, all based on our Western understanding of endorphins and the workings of the autonomic nervous system, so the honest answer is that we really don’t fully understand it, but we do know that it works. There are different types of acupuncture, and different techniques. Dr. Turner prefers those involving needles (not air or other hocus-pocus), but these require the supervision of a licensed veterinarian. Many veterinarians have now been trained in acupuncture.
Chiropractic: The theory here is that you can deal with pathologies and dysfunctions created by vertebral subluxations. The problem is that if humans need treatments every 4 – 5 days for acute problems, how do equine chiropractors get away with every 30 days? And if adjusting a 180 lb man takes a bit of effort, how can a human adjust a 1500 lb horse? Dr. Turner believes that horses often give themselves adjustments in turnouts, etc., and that owners can also help horses adjust themselves with stretches, etc. There may be some benefit to equine chiropractic in certain situations. (He did not elaborate, however).
Massage: Massage proponents claim that it improves circulation, dilates blood vessels, stimulates lymph flow, relaxes spasm in muscles and relieves tension. Improvement in blood flow and relaxation of muscles has been thermographically demonstrated in a study on horses that were prone to tying up (they were studied after a period of exercise to the point of cramping, and then received massage to only one side of their backs—both sides were then looked at with thermography. The massaged side had normal blood flow, and no evidence of spasm compared to the untreated side in all horses studied).
Therapeutic Cold: Best in the 24 – 48 hours after injury, it works to retard swelling, prevent hematoma formation, and to cause capillary constriction. Unlike humans, horses DO NOT exhibit a reflex increase in blood flow on rewarming. Instead, blood flow is diminished, and gradually returns to normal, with metabolism also lowered and gradually returning to normal. There is also an analgesic effect that can last for several hours, which can be used to our benefit if ice is applied PRIOR to painful treatments.
Heat: Heat should NOT be used in the first 48 hours after injury. It causes vasodilatation, increased oxygen consumption, and increased metabolic demands in the involved tissue. There is also a reflex vasodilatation, resulting in increased vascular permeability—an important consideration if toxins are present (i.e., cellulites or abscess). The affected area should be wrapped afterward to prevent stocking up.
Magnets. The claim is for increased bloodflow and metabolism, increased tissue repair, pain relief, and pain relief. However, thermographic evaluation of the claims showed no temperature change but the thermal PATTERN was different in that it lit up in the pattern of the magnets. This suggests that the MECHANISM is probably not through simply increasing blood flow.
Therapeutic Ultrasound. Alters cell permeability, and applies deep heat. Frequency determines depth of penetration. Has been used to soften scars, treat pain, but best role is probably to warm-up tissues prior to work.
Electrical Stimulation: rhythmic or tetaic contraction of muscles to treat muscle spasms.
Photon light therapy: claims of decreased pain and swelling, improved blood flow and reduced production of oxygen free radicals. Studies have not shown benefit in healing of normal tissues, but useful in treating the hard-to-heal treatment failures.
Extra-Corporal Shock Wave Therapy: Claims of reduced pain, accelerated healing by unclear mechanism using high pressure low frequency sound waves. Can be used in both focused and radial manner. Has definite analgesic effect. Ideal uses/indications still being determined.

Exercise is one of the best therapies. Dr. Turner HATES to rest horses. If there is a way to keep working the horse, then the horse should keep working. If you take the horse off work, the hardest thing in the world will be to get it back working. Fitness and strength are our BEST tools for preventing injury.

Rehabilitative exercise falls into 4 categories:

active = modified program (avoid movements that would aggravate injury)
reduced = trail or lower level of intensity
passive = range of motion exercise, human or device moves joints FOR the horse
resistive = moving the joints against resistance (i.e., swimming the horse)

Joint mobilization can begin very early, even post-arthroscopy, with beneficial effects with regard to restoring normal joint function. Cooling with gel packs recommended afterwards.

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