What’s All the Talk About Insulin? Hyperinsulinemic Associated Laminitis

Thirty years ago, laminitis was usually a career-ending diagnosis, if not a life-ending one.  Aside from mechanical support and pain management, little was known about the contributing factors associated with laminitis and the multitude of clinical factors that affect the severity, outcome, and likelihood of recurrence.  Today, we know a great deal more about metabolic laminitis and specifically the role that insulin plays in mediating this disease process. 

Current data shows that horses with an elevated baseline insulin value are at a higher risk of developing hyperinsulinemic associated laminitis (HAL).  The ability to establish a direct relationship between elevated serum insulin levels and the onset of laminitis has enabled veterinary practitioners to make great strides in combating this disease process. 

Hyperinsulinemic Associated Laminitis Diagnosis and Treatment

When presented with a patient suffering from HAL, the first step is to determine just how high the insulin values are.  Seasoned practitioners can usually estimate the severity of hyperinsulinemia by assessing the extent of regional adiposity (fat deposition in the horse’s body).  The most common site of regional adipose tissue deposition are the crest of the neck, on either side of the withers, along either side of the horse’s topline, and on either side of the tail head.  The greater the accumulation of fat in these areas, the higher the baseline insulin value in that patient.  Bloodwork, in the form of a metabolic panel, is then used to quantify those observations to establish an appropriate therapeutic regimen and track progress throughout the treatment period. 

If the patient is actively suffering from HAL, all therapeutic methods are implemented in an attempt to slow down the damage associated with the laminitic process.  In addition to dietary management and the eradication of starch from the horse’s feed, medical intervention with metformin has proven to be a very successful strategy in our practice. 

Metformin increases tissue sensitivity to insulin in the patient. Insulin is a signaling molecule which instructs cells to recover glucose (starch/sugar) from the GI tract to use to power cellular processes.  In horses with hyperinsulinemia, the tissues of the body aren’t responding to the insulin currently being produced, so, the body produces more insulin, leading to a hyperinsulinemic state. 

The physiologic process by which elevated insulin values lead to laminitis are still unknown.  However, current research shows that insulin is capable of binding to receptors in lamellar epithelial cells which stimulates excessive growth of the horn tubules, leading to the traditional elongated hoof structure of chronically laminitic feet.  Metformin helps to increase tissue sensitivity to insulin which in turn down regulates the body’s natural production of insulin. 

Hyperinsulinemic Associated Laminitis Treatment Outcomes

The success of treatment of horses with insulin dysregulation is highly dependent upon the severity of the HAL, the chronicity of the disease process, and the condition of the hoof capsule.  Optimal outcomes are associated with high compliance on the part of the horse owner when it comes to implementing therapeutic regimens and dietary management, as well as the employment of a farrier who is willing to work with your veterinarian when making strategic decisions around trimming and shoeing your horse. 

These patients require several series of radiographs over the course of their case in order to ensure optimal trimming is being performed in addition to tracking the sole depth of the patient.  Most cases, when identified in their chronic stages, usually require many months to restore physiologic function of the hoof capsule and achieve an acceptable level of comfort on the part of the patient.  Depending upon the integrity of the hoof capsule, metabolic stability, and comfort of the patient, these patients can sometimes return to their previous level of work.  While not all cases have the perfect outcome, with the knowledge and medical advancements the veterinary profession has seen over the past few decades, it is absolutely worth trying to combat hyperinsulinemia associated laminitis. 

What is Cellulitis?

Last night when you fed your horse you didn’t notice any issues as you performed your quick “once over” before rushing back out the barn door. But this morning they have a severely swollen leg, and they are hobbling around.

What happened? 

The list of possibilities isn’t terribly long, but there are serious things on it: fractures, hoof abscesses, laminitis, joint infections, and cellulitis.  Of course, fracture is the one that no one wants to hear and has significant ramifications.  Laminitis and abscesses typically don’t have the significant swelling described in the “case” above.  Joint infections would likely have been associated with trauma or a recent joint injection, and the swelling would likely be associated with a particular joint, not the entire leg.  That leaves this horse with a likely case of cellulitis. 

If you haven’t ever seen a case, they can be impressively swollen, and this can happen relatively quickly (overnight)! See below for an example.

What is cellulitis

Cellulitis is an infection of the deeper layers of the skin and the subcutaneous spaces.  The pressure and inflammation make it extremely uncomfortable for the horse.  They are usually very painful to the touch (maybe not everywhere they are swollen, but some portion of the swelling), and there is a lot of heat. Severe cases can have serum oozing from the skin. The horse may have a mild to moderate fever as well.

What causes cellulitis?

The infection can initiate from an obvious recent wound, bed sore, “scratches”, or other minor scrapes. It could also be a result of a more significant laceration from days before that seemed to be healing in the right direction.  Another common route that these can begin is secondary to a hoof abscess.  The infection begins in the hoof and then in the right set of circumstances, manages to take hold and cause further infection higher up the leg.

How is cellulitis treated?

If you notice the swelling before it is as extreme as the picture above, getting medical attention could prevent it from becoming such an advanced case.  Medical attention usually consists of antibiotics and anti-inflammatories systemically.  On occasion, a “regional limb perfusion (RLP)” may be justified.  An RLP is a way for the veterinarian to get very high concentrations of antibiotics to the area of concern using a tourniquet and antibiotics directly infused into the affected limb.  Hydrotherapy (cold hosing) is also often indicated. 

Managing cases of cellulitis early is paramount to preventing long term ramifications such as lymph damage (lymphangitis), or laminitis.  Lymphangitis is an inflammatory process in the normal lymph drainage of the limb, and can leave the limb permanently swollen.  If there is enough swelling in the leg during the cellulitic process, it could cause enough vascular alterations to damage the laminae of the foot, causing laminitis. 

If you find your horse with a sudden non-weight bearing lameness (or barely weight bearing), we would always tell you that it is justification for a phone call to your veterinarian, and most likely a visit.

Street Nails – Call your vet immediately

No matter how safe their environment may be, horses will always manage to find trouble. Unfortunately, a not-so-uncommon equine emergency is a sharp object that has penetrated through the bottom of the hoof, also known as a street nail. Any penetrating injury to the bottom of your horse’s foot is an emergency, and timely assessment is essential for the best outcome.

The number one rule for the horse owner is NEVER REMOVE THE NAIL before talking with your veterinarian! The exact location of the nail is crucial for determining the best treatment for your horse. ALWAYS call your vet first! Sometimes a photo can help your vet offer the best advice before evaluation.

Nail prior to removal

In general, foreign objects to the back third of the foot present the highest risk because of the position of important structures and the consequences of infection.

Nail Prior to Removal

Your vet will take radiographs of your horse’s foot prior to removal of the nail to determine its exact location. If the nail has been removed or fallen out, special dye can be injected along its tract that will show up on the radiographs, but it is more informative to leave the nail in place if possible! If the nail falls out prior to evaluation, save it and mark the depth of its tract if possible.

Dye injected along nail tract

The next step is beginning treatment, depending on the location of the nail. If the nail is well embedded, temporary numbing of the horse’s foot enables non-painful removal. The nail tract will then be flushed to remove dirt and debris. A bandage, sometimes including a drawing poultice, is applied to ensure the tract remains clean during healing. Sometimes a hoof abscess can develop during healing. Depending on the nail location, a technique called a regional limb perfusion may also be used.

Performed on the sedated horse, a regional limb perfusion involves the placement of a tourniquet on the limb above the hoof, allowing for antibiotic injection into a vein below the tourniquet. The tourniquet is left in place for up to 30 minutes to allow a higher concentration of antibiotic in the limb below the tourniquet.

If the location of the nail is in a critical location, such as through the center of the frog or potentially involving the tendon sheath or navicular bursa, prompt surgical flushing at a referral hospital is the best treatment to minimize the risk of fatal or career-ending infection.

Timely treatment of any penetrating wound to the foot is imperative for the best outcome!

Caring for Your Senior Horse

At what age is a horse considered geriatric or senior? Does owning a senior horse mean that he must eat a feed labeled as a “senior” feed? As always, the answer is, it depends. Our horses are living longer lives than ever, thanks to an evolving understanding of the needs of geriatric horses and our ability to provide high quality care. There is no set age cutoff as to when a horse is considered geriatric, but most experts agree this can be around age 20. However, age is just a number, and many horses are still active and competing into their twenties, while others are happily retired. The main issues we see in our older horse population include dental disease, altered dietary needs, metabolic disease/PPID (Cushings), and arthritis.

 

Photo Courtesy PugnoM on Flickr

Dental Changes

The ideal time to begin focusing on your horse’s regular preventative veterinary care is when he is young. Horses receiving regular preventative care, especially veterinary dentistry, preserve their teeth longer and can age more gracefully. Waiting until signs of dental disease or difficulty chewing are observed often indicates advanced disease and more limited treatment options. Most horses benefit from yearly dentistry, which includes a thorough sedated oral exam with a dental speculum, light source, and mirror. A thorough oral exam is vital to accurately assess, document, and treat any issues.

Horses suffering from abnormal dental wear, cracked or missing teeth, or severe periodontal disease may require more frequent care. Even though horse teeth are described as “long rooted,” they do eventually wear out, so proper care ensures the longest possible life of the tooth. Common dental issues in older horses include fracture of cheek teeth, complete expiration or wearing out of cheek teeth, loose/painful teeth, and periodontal disease. The incisors can also be affected by similar conditions.

Staying on top of your senior horse’s dental care helps ensure that he gets what is needed from his diet. Sometimes severe dental disease and impaired chewing ability necessitates eliminating hay from the diet entirely. Complete feeds are formulated specifically for horses that can no longer chew hay effectively. These diets have greatly improved the quality and length of life for senior horses with compromised teeth.

Nutritional Changes

Nutrition recommendations for the geriatric horse are formulated around maintaining an ideal body condition. In the geriatric horse, this can be complicated by difficulty chewing, poor teeth, metabolic disease, and decreased ability to digest fiber and protein. For older horses in good weight and with adequate dentition, little dietary change may be required. For older horses who have difficulty maintaining weight and/or compromised teeth, complete feeds as mentioned above can help. These feeds are high in easily digestible fat, fiber, and protein, and are designed as easy-to-chew. They are formulated to replace hay entirely for those horses that can no longer adequately chew hay.
Adding water to soften the feed can reduce the risk of choke and ensure additional water intake. Feeding recommendations are often listed as pounds of feed per day depending on whether the horse is also eating hay, so it is important to weigh out your horse’s portion so that any necessary adjustments can be made more accurately.

Metabolic Changes

A curly haircoat and muscle loss over the back aren’t just signs of aging- They can indicate a common underlying condition: equine pars pituitary intermedia dysfunction, more commonly known as PPID or Cushings disease. This is a treatable (but not cureable) condition that is very common in geriatric horses, resulting in hormonal imbalances and symptoms such as delayed shedding, curly hair coat, muscle loss over topline, increased drinking and urinating, personality changes, and increased susceptibility to infections and laminitis. Diagnosis is made by a blood test as well as by history and clinical signs. Management involves daily administration of pergolide (Prascend) tablets, which help restore normal hormone levels and alleviate the clinical signs of the disease.

Equine Metabolic Syndrome (EMS) is a separate metabolic condition, but it sometimes occurs in conjunction with PPID. EMS horses typically show signs of being an “easy keeper”- cresty neck, regional fat deposits behind the shoulders and at the tail head. Horses with EMS are more susceptible to laminitis and usually have a higher baseline insulin level than normal. EMS horses are managed with strict attention to diet (minimizing sugar and starch) and exercise to help them maintain a lean body weight.

Joint and Muscle Changes

Just like us, aging horses suffer from daily aches and pains. An examination with your vet can help identify major and minor issues and

Photo Courtesy nikki_tate on Flickr

determine what treatment plan works best for you and your horse. Many options are available to keep our old horses comfortable.
Nutraceuticals (supplements) are very popular, although many of these products lack proof of efficacy and ingredients. More researched options include medications such as adequan (administered intramuscularly) and Legend (administered intravenously). These medications help provide the components necessary to keep joints healthy.

Joint injections target individual joints to reduce pain and inflammation and improve mobility. Non-steroidal anti-inflammatories such as Equioxx are also helpful, along with acupuncture and chiropractic care. Stable management is equally important- maximum turn out time allows horses to move at will, and monitoring herd dynamics ensures that older horses are not prevented from accessing food and water. In addition to these considerations, regular veterinary and farrier care will help your senior horse enjoy his golden years with you.

As always, if you have any questions about caring for your senior horse, please contact your veterinarian who can offer a personalized plan to help keep your geriatric horse happy, healthy, and comfortable well into their senior years.

Lacerations- When do you need to call the veterinarian?

 

By Dr. Shane Baird

HorseWoundAs horse injuries go, cuts, scrapes, and bruises of all shapes and sizes are common – the challenge is learning when veterinary intervention is required.

Is There Joint Involvement?

One of the most critical factors for laceration severity is the location of the laceration.  A solid “rule” to keep in mind is that if the wound is over an area that “bends” and appears to be fully through the skin, it justifies at minimum a call, and likely a visit from a veterinarian.  Cuts that seem to be no big deal, but are located directly over a joint, can be disastrous for the horse, while something that looks horrible at first glance but only involves skin and muscle can heal without causing any problems.

The lower limbs of horses don’t have a lot of tissue between the skin and the joints or bones. This “lack of padding” makes it easy for a cut that looks simple to penetrate into the joint.  Joints open to the outside world are open to infections and if infected, can become debilitating for a horse due to the arthritis associated with the process.

Severe Wounds Without Joint Involvement

Severely traumatic wounds, where tissue (skin, muscle) have been damaged or are just missing, can greatly benefit from prompt veterinary attention.  Proper removal of tissue and thorough cleaning of these wounds will speed the healing process significantly.  Though some of the skin may be missing from a wound like this, with some creative suturing, what remains can be used as a natural bandage, even if only temporarily.  At times, if healing is taking a longer than expected, there is justification for skin grafting techniques, even in an ‘in the field’ situation.

Head Woundshorse-943771_1920

Though the head can heal quite well on its own, lacerations to the eyelid region and around the eyes often warrant closer examination.  If your horse has an injury like this and they have no desire for you to even look, much less touch and clean the wound (which a fairly common response!), please call your local veterinarian so that things can be tended to (likely with sedation).  Trying to fight with the horse can quickly lead to other issues or injuries.  With sedation these wounds can be treated without further injury to the horse or any humans.

Tips on Pre-Veterinary Visit Wound Care

bandage on the leg of horse
bandage on the leg of horse

If you do decide that a veterinarian should see the laceration, here are some basic rules to follow:

  • Do NOT wash the wound with the hose. This can force dirt and debris deeper into the wound.  Using a paper towel or gauze with dilute betadine, clean the wound of obvious dirt and debris.  If the wound has potential to get dirty again before the veterinarian arrives, place a light bandage over the wound.
  • If there is a chance that the wound will need suturing or stapling, DO NOT use anything “blue or purple in color.” While efficient at stopping bleeding, these dusts and powders can be very damaging to healthy tissue and create a larger mess than before.
  • If your vet is not going to see the wound, and it doesn’t need a full bandage, a little bit of ointment (triple antibiotic is good) will help to keep the wound clean and moist.
  • If bandaging, make sure there is “padding” between the skin and any “vetwrap” like product.

As always, if there is any question, give your veterinarian a call. After a conversation you can both make a decision of whether your horses’ laceration should be seen or not.

 

 

 

The Pre- Purchase Exam- Should You have Radiographs or Ultrasounds Taken?

cowgirl-419084_1920By Dr. Shane Baird

After weeks of searching, you have finally found the right horse.  He’s everything you’ve ever wanted.    What now?

A veterinary pre-purchase exam should be the next thing on your mind!  At a minimum, an active and passive exam by an equine veterinarian should be performed prior to purchase, but what about additional diagnostic imaging?  Regardless of whether or not you’re buying your next equine athlete or your trail partner for the next twenty years, radiographs and ultrasound imaging may be in your best interest to protect your investment.

The Right Horse is the Right Horse For You

In all the pre-purchase exams we’ve performed, we have yet to find a “perfect” horse, and a horse that may be right for your goals, might not be the right horse for someone else’s.

It is important to remember that it is not the responsibility of the veterinarian to “pass” or “fail” a horse.  What you should really be asking is, can you and your horse live with the faults identified during the exam and the limitations that arise because of those shortcomings? We are there to provide you, the buyer, with information pertinent to the health and soundness of this horse so you may decide how the horse may fit in your life and barn.

In some situations, it’s easy to determine whether or not the horse in question will stand up to his intended purpose.  In other situations, we must rely on additional diagnostic means to answer these questions, thus enabling you to make a more informed decision.

When Should You Get Digital Images?

lawn-2599037_1920Let’s say that your veterinarian has completed the basic pre-purchase exam and that a few issues have been discovered that require additional consideration.  You may decide that the findings are small enough that they don’t impede your future plans with this horse, in which case the exam may not need to go any further. However, you might decide that the findings could deter you from purchasing the horse.  This is when we would recommend further diagnostics in the way of nerve blocks, in addition to radiographs and possibly ultrasound.

Ultrasound technology is far more portable and convenient to use stall side than it was even just a few years ago.  If there is any palpable soft tissue issue, but no lameness is detected on exam, then a scan is completely justifiable, especially if the horse is responsive to palpation of the area.  Ultrasound can help us to see issues of the past and try to understand if they could become an issue in the future.

Similarly, radiology (x-ray images), are often the quickest way for us to understand a mild lameness that is identified in the dynamic portion of the exam.  Technology these days enables us to develop radiographs within seconds as they appear on a computer screen.  We may determine that there is a mild amount of arthritis in a specific joint or that this horse has significant degenerative changes that may impact his ability to perform as desired, or as long as desired.  Radiographs, and digital/stall side images are the best way to differentiate between the two.

While forecasting the future is always the most difficult part of the pre-purchase exam, advanced diagnostic imaging can make that picture just a little clearer! Awoman-with-horse-2631173_1920 complete exam, and imaging to help understand any issues uncovered, is our best shot as veterinarians to help you, the buyer, and make sure this new horse is truly the “right one for you!”