Thursday, February 21, 2019

The Challenge of Cellulitis

Prompt, aggressive treatment is needed to stop this sudden, painful skin infection—and to prevent it from becoming a chronic condition.

Cellulitis On A Horse's Leg
Few situations shout “Emergency!” louder than a horse refusingto bear weight on a grossly swollen leg. Suddenly one task supersedes the whole day’s plans: Call your veterinarian. washingleg

“A lameness with significant swelling should be seen by a veterinarian as soon as possible,” says Meg Hammond, DVM, of Woodside Equine Clinic in Ashland, Virginia. You’ll want to keep the horse still while you wait---if it’s an injury, making him walk even a few steps could make it worse.

The greatest fear, of course, is that the lameness is caused by a fracture or another severe orthopedic injury. But occasionally the source of the problem is something less dire yet still a challenge to treat: an infection called cellulitis.

“Cellulitis is somewhat common in the horse world, but it can be frightening for an owner,” says Hammond. “The leg can be normal one day and double or triple in size overnight. If the leg is infected, the swelling will not resolve with nursing care alone.”

Immediate, aggressive therapy with intravenous antibiotics and anti-inflammatory medications is needed to bring the swelling down and control the infection as quickly as possible. Most horses readily recover from a bout of cellulitis and return to their previous level of activity. But life-threatening complications are possible, especially if treatment is delayed. And for some horses, the initial bout of acute cellulitis will be just the first of many chronic flare-ups.

Making that emergency call to your veterinarian is the most important first step if your horse develops cellulitis. Here’s what you need to know about what comes next.

HOW THE INFECTION DEVELOPS


Normal skin consists of three layers: the epidermis, the tough, external shield that forms one of the body’s first lines of defense; the underlying dermis, the flexible, sensitive layer that contains glands, hair follicles, capillaries, nerves and other structures; and the subcutis, which is made up largely of connective and fatty tissues.

Cellulitis develops when bacteria penetrate below the epidermis and multiply in the subcutis. The infection is diffuse, meaning that it spreads over a wide area without a specific point of origin. How the bacteria penetrate the dermis and subcutis is often unknown---a situation that is called primary cellulitis.

“In nearly half the cases we never really know what started the infection,” says Margaret Mudge, VMD, DACVS, DACVECC, of Ohio State University. “There is no known trauma or obvious wound. We don’t know if the bacteria were already in the horse’s body or if they were introduced through the skin. They may get dragged in through tiny punctures that we can’t see. They may get through the skin if there is enough damage to the underlying tissues that the barrier is compromised.”

On the other hand, secondary cellulitis develops when bacteria gain entry through a wound, surgical incision or another known route. Breaks in the surface caused by dermatitis, the technical name for inflammation of the outer layers of skin, can also allow bacteria in. “When the integrity of the skin is compromised, bacteria can gain entrance and replicate in the underlying tissue,” says Hammond. “It is impressive what can happen when that barrier is damaged.”

A variety of bacterial species have been implicated in cellulitis, but the infection is usually caused by Staphylococcus aureus and Streptococcus species. “These are common bacteria that are often found on skin,” Mudge says. Other bacterial species that may be involved include Enterococcus and Actinobacillus species. “Occasionally, cellulitis can be due to infection with Corynebacterium or Clostridium or a gram-negative bacterium such as Escherichia coli,” says Callie Fogle, DVM, of North Carolina State University.

Secondary cellulitis can develop anywhere on the body where a wound occurs. Primary cellulitis usually develops on a leg, and most often the hind legs. “The term ‘cellulitis’ is very general, referring to infection under the skin and sometimes involving the skin,” says Mudge. “But when we talk about cellulitis in horses we tend to think of the hind limb.” Even when it initially seems mild, cellulitis is not an ailment to take lightly. The swelling can progress quickly, even within a few hours, to the point where fluid leaks from cracks in the overstretched skin.

Plus, if the infection is not controlled quickly, a number of serious complications can develop. For example, the bacteria may spread from the skin into the deeper tissues and structures of the leg. “A particularly aggressive or resistant bacteria may cause tissue necrosis0 or a more deep-seated infection, which in rare cases can affect the bone, tendon or synovial structures such as a joint or tendon sheath,” says Hammond.

Laminitis is also a possibility. “It’s usually a support-limb laminitis but it can also be laminitis in the affected leg,” says Fogle.

Systemic infections, such as sepsis0, can also occur. “Horses can have further problems if the bacterial infection does not stay confined to that limb and goes throughout the body,” Fogle says. “The horse can become very sick from systemic infection. These are all risks with severe cellulitis, but are more likely in cases with a delay in the start of therapy.”

IDENTIFYING THE PROBLEM


Cellulitis is most common in a hind limb, but it can also occur in a front leg or on other parts of the body. “The classic form of cellulitis is unilateral, affecting just one limb, but it can affect multiple limbs,” says Fogle. Here are the common signs:

Swelling that is dramatic and appears suddenly. “The leg is usually diffusely enlarged, sometimes all the way from the foot up to the stifle or beyond, and the typical case is generally swollen from at least the foot to the hock,” says Mudge. The leg may be two or three times larger than normal, and the swelling will be firm to the touch.

Severe pain. “These horses are generally very lame, but often the pain occurs when advancing the limb rather than from standing on that leg; it’s difficult or painful to move the limb,” Fogle says. “Generally, the horse will bear reasonable weight on the affected limb when not being asked to move, compared to a non-weight-bearing lameness that is commonly seen with a fracture or a joint infection.”

Heat. “The leg is usually very warm and painful to the horse if touched,” says Mudge.

Fever. The horse’s temperature is likely to be elevated, and his heart rate may be increased. His overall attitude may be dull, and his appetite low.

Wetness on the surface of the skin may be noticeable, especially if the swelling is dramatic. “Depending on how severely swollen it is, the leg may be oozing serum, weeping through the skin,” says Mudge. These breaks in the skin may have been caused by the initial trauma, or the skin may be so overstretched that the yellowish serum seeps out.

TREATMENT PLANS


Once cellulitis has been diagnosed, treatment will begin immediately. “The longer the leg stays swollen, the greater the risk for complications,” says Fogle. “It is crucial to treat acute cellulitis right away and be as aggressive as possible, within the owner’s financial ability.”

The primary treatment is an aggressive course of intravenous antibiotics as well as nonsteroidal anti-inflammatory medications such as phenylbutazone to address pain and inflammation. Initially a broad-spectrum antibiotic may be administered, but once the results of any cultures are in, the veterinarian may switch to another antibacterial agent that more specifically targets the source of the infection.

Cold hosing is an easy and fairly effective way to address the pain and swelling of cellulitis. “Cold water therapy is helpful, whether it’s one of the fancy boots that recirculates cold water, or just cold water from a hose,” says Fogle.

Bandaging may also help to control the swelling, if the horse will tolerate it. “Some horses will be so painful that they won’t tolerate having a tight bandage on the leg,” says Mudge. “They may protest the bandaging but tolerate cold hosing. Cold therapy can be a good way to reduce the heat and potentially some of the swelling.”

Finally, steroids might be an option, but they must be used judiciously. “Steroids are commonly used by veterinarians to address minor distal limb swellings, but we can run into trouble with steroids to treat severe cellulitis because they can effectively mask whether or not we’re successfully resolving the bacterial infection in the limb,” says Fogle. “Short-term steroid use with a bout of acute cellulitis is OK, but you wouldn’t want to use it very long.”

As a horse’s condition improves, walking can help improve his circulation and pull fluid out of the leg. “Exercise is not feasible when a horse is in an acute bout of cellulitis,” says Fogle, “but getting him moving once the severe symptoms are starting to wane is important.”

Milder cases of cellulitis may be treated on the farm, especially if the owner is comfortable with administering the pain medications and antibiotics as well as cold hosing and bandaging. However, says Mudge, “there are horses who are so painful that they need to be managed in a hospital with more continuous or higher powered pain medications.”

Serious complications might also warrant hospitalization. “Some horses become systemically ill from this infection,” Mudge says. “If the horse has a fever and has gone off feed or is showing signs of laminitis, that horse might be referred to a hospital for more intensive treatment.”

THE ROAD TO RECOVERY


Most horses who develop cellulitis recover completely, especially if treatment begins promptly and they start to respond within the first 24 to 48 hours. “The majority of horses will respond to aggressive medical treatment,” says Fogle. “Often those horses won’t develop any of the chronic effects or complications of cellulitis.”

Horses with secondary, rather than primary, cellulitis tend to recover more quickly. “The prognosis is generally better in the cases where there’s a known injury such as a laceration or some kind of trauma, or cellulitis related to a surgical procedure,” Mudge says. “Those horses seem to do a little better than the horses that have recurrent bouts of primary cellulitis that are not due to a known skin injury. The primary cellulitis cases are often more challenging to resolve in the long term.”

But cellulitis can have long-term effects. Extreme inflammation can stretch and scar tissues enough to compromise the lymph system’s ability to draw out excess interstitial fluids (the fluid that fills the spaces between body cells) and return them to the bloodstream. “Damage to the lymph vessels will interfere with normal drainage of fluid from the limb,” Hammond explains. “With this decreased efficiency of the lymph system, these subcutaneous tissues may always hold a little extra fluid, making the leg appear slightly swollen even after it has healed. This is most likely to happen in the more severe cases or the ones that are not treated early.”

The change in the leg’s appearance may be permanent. “I warn owners that even when horses respond well, they may end up with a leg that is slightly bigger than the other one,” says Mudge. “Even if everything goes well and the horse makes it through and recovers without residual lameness, there may be some limb enlargement. It is yet to be determined whether prolonged bandaging or using things like compression cold therapy make a difference in the final outcome, though these strategies make a lot of sense in continued treatment for these horses. At this point in time, however, we don’t have strong evidence to say whether those will ultimately improve the cosmetic outcome.”

FROM ACUTE TO CHRONIC


Unfortunately, even a single episode of cellulitis can leave a horse susceptible to the chronic form of the condition---repeated episodes of severe, painful limb swelling. “A horse who has recovered from cellulitis is more likely to have a recurrence in that same limb,” says Hammond.

One reason may be that the infection and extreme swelling did some permanent damage to the skin, leaving it more porous. “Inflammation can cause damage to the skin and decrease its effectiveness as a protective barrier,” says Hammond.

Another possibility is that the permanent damage to the lymphatic and blood circulatory systems diminishes the ability to mount a new immune response. “We think that these repeat episodes may be due to scarring and permanent impairment of the venous and lymphatic systems in that limb,” says Fogle. “Once those systems are impaired, the horse is less able to fight infections in that limb. That limb is more vulnerable, and even a small amount of bacteria is capable of starting an infection.”

Chronic flare-ups of cellulitis behave a little differently than the initial acute disease. “It may come on more insidiously than suddenly, compared to acute cases,” Mudge says. And the physiological source of the swelling may differ as well: “The swelling with chronic cellulitis is commonly thought to be poor circulation and inflammation, with less contribution from bacterial infection of the deeper tissues,” says Fogle.

Horses prone to chronic cellulitis will need to be closely monitored; even the tiniest of wounds on the leg may spark a new bout of pain and swelling. “One of the things that owners can do to try to prevent recurrence in that limb is to be vigilant about feeling the skin in the fetlock and pastern area, checking daily for any scabs, scratches or abrasions,” says Fogle. “It’s wise to clip and clean any breaks in the skin on that limb with a gentle soap and allow it to dry.”

Regular turnout and exercise are also recommended to encourage circulation in the affected leg---with some cautions. For one, turnout in wet grass is not ideal. “When the skin is wet it becomes softer and more vulnerable to being nicked or scraped, and it’s easier for bacteria to gain access,” says Fogle. “Keeping the at-risk horse in until the grass is dry is best.”

Bandaging can help to limit swelling when the horse is in a stall. “Several different types of bandages can be useful,” says Fogle. “A quilt and polo wrap or special bandages called short stretch bandages can be used to try to minimize the amount of edema that develops when a horse is stalled. Once these horses are turned out, they don’t need the bandaging.”

Shipping boots are a good idea while in the trailer, and polo wraps can protect the horse’s skin during exercise and competition. “Owners with horses that have chronic cellulitis are usually pretty careful about protecting the limb while they are riding or when trailering,” says Fogle. But the precautions are worth it: “The exercise is really helpful, to improve the blood flow to the limb and improve the circulatory system and lymphatic drainage,” she says, “so it’s often best to continue using the horse, as long as he is sound. As long as you protect the skin, exercise is great.”

Proactive antibiotic treatment is sometimes helpful, too. “I have several owners who have horses affected with chronic cellulitis,” says Fogle. “When they identify a break in the skin, they contact their veterinarian and get the horse on a round of antibiotics to try to prevent another exacerbation of cellulitis. They have developed a very successful proactive approach to try to manage the limb and prevent further bouts of cellulitis.”

PREVENTATIVE MEASURES

Why some horses develop cellulitis while others don’t isn’t well understood, so it’s impossible to identify definitive ways to prevent the infection. “Sometimes in a horse that had some dermatitis or we find a small scratch, we suspect that was what set it off,” says Margaret Mudge, VMD, of Ohio State University, “but there are many horses that have mild dermatitis or lots of cuts and scrapes that never develop cellulitis.”

Nevertheless, taking some basic precautions to protect the skin on your horse’s legs will not only keep him healthier and more comfortable, but might just help you ward off this terribly painful infection:

Clean and disinfect even the smallest of wounds. “As soon as you notice anything abnormal, it should be treated promptly and appropriately,” says Meg Hammond, DVM, of Woodside Equine Clinic in Ashland, Virginia. Call your veterinarian for help with deeper, more serious wounds.

Maximize turnout and/or get the horse regular exercise. Moving around stimulates healthy circulation in any horse, but it’s especially critical for those prone to cellulitis.

Keep the skin dry. Muddy, sloppy turnouts are unavoidable for farms in wet climates at certain times of the year. Do, however, make sure horses have access to dry shelters where they can find some respite. Laying gravel in low, muddy areas can also help keep their legs cleaner. Bringing turned-out horses inside once a day will give you the opportunity to clean and inspect their legs and let them dry out.

Go easy on the shampoo. Over-exuberant soaping up will dry out skin and may lead to cracking.

Groom carefully. Removing long hair on the legs can help keep the skin drier, but be careful not to scratch the horse with the clippers. Also use only soft brushes and rags on the legs.

Sterilize grooming and bathing equipment periodically. Newer washing machines have a sterilization option that can heat rags and towels to a temperature high enough to kill most bacteria and other pathogens. Brushes and other tools can be sterilized by scrubbing them with soap and water before soaking them in a bleach solution and laying them in direct sunlight to dry. Avoid sharing tools among horses, especially if one is prone to chronic cellulitis.

Managing a horse prone to chronic cellulitis requires diligence. But with attentive care, there’s no reason he can’t live a long, healthy and productive life.

Thursday, February 7, 2019

Jim Wofford: Now's Your Chance

Going into an off-season quiet time, you can plan for a fitter and happier horse next time out. 

By: Jim Wofford

Horse Walking

 Winter is the time to plan for improvement. Long walks during this time give your horse the strength and fitness to perform better in the coming year. While you are conditioning your horse, leave your headphones behind. If you disconnect yourself from the natural world, you are a menace to society and a danger to your horse. Headphones are mental “bling”—they tell me that your riding is about you, not about your partner. When told they are a defense against boredom, I ask, “How can you be bored when you are connected to the most wonderful creature in creation?” As your horse makes a long series of solitary footprints, consider what author John Moore said, “Wherever man has left his footprint in the long ascent from barbarism to civilization, we will find the hoofprint of the horse beside it.” Think about the horse’s role in society and your particular horse’s role in your life. Think about the ethics of owning an animal that depends upon you for both his livelihood and his life. Think about your horse, not yourself. © Amy K. Dragoo/AIMMEDIA

This might be my favorite time of year, when most of the big eventing competitions are over. I think of this period as “Now’s my chance.” While the horses in my program are having a much-needed rest, their riders and I are planning for future success.

By “success” I don’t necessarily mean winning, although that helps. I really should say I am looking for “improvement.” I go through this process regardless of the current level of the horse and rider. I want my riders to set goals for themselves, but they have to be realistic goals. If we are dealing with a 6-year-old Thoroughbred who ran until he was 4, it is rarely realistic to say, “Next spring I want to win a CCI*.” The Thoroughbred might have successfully completed a competition at the Preliminary level at this point, but he is not yet competitive.

Chances are this Thoroughbred’s dressage is still very much a work in progress, and although he’s obviously talented, his youthful exuberance causes him to have an occasional show-jumping knockdown. His talent shines on cross country, but most riders and trainers will not have let him run at speed yet. That will come with maturity. Many times, horses of this type will have to work their way up the levels with few top-five placings to show for their efforts until they get into the rarified atmosphere of three- and four-star competition. Despite the change in format from Classic to short, at the middle and upper levels stamina and speed are still determinative factors, and this is when Thoroughbreds start to show their talent and the results of their riders’ careful, years-long preparation.

Although I am proud that I can help horses and riders at every level, I tend to keep my eyes on the upper levels of eventing, and most of the upper-level event horses are 70 percent or more Thoroughbred. I counsel my riders that if a nice non-TB prospect comes along, they should keep the horse’s breeding in mind. Non-TB horses usually find the dressage and show jumping easy, but take a bit longer to understand the cross country and rarely have the ability to gallop at speed.

A Chance to Improve Soundness and Fitness


I mentioned earlier that my horses take a break from competing at this time of year. I am a bit old school about this. I still think in terms of a two- or three-month competition season followed by a rest period and then by another period of preparation for competition. As you start your break with your horse, get your vet to examine him. Now’s your chance to have your vet diagnose and treat any lingering physical problems he might have.

When you start conditioning for your horse’s new season, I want you to use the most powerful tool you have: the walk. That’s right, I want you to walk your horse into shape. My reasoning is simple. Both the walk and the gallop are four-beat paces. When you walk your horse, you are galloping in slow motion with little concussion and a low risk of injury.

At this juncture you may be thinking, “Walk? But Jim, what about trot sets?” The vast majority of horses who I train these days are preparing to compete in a short-format event rather than a Classic (which included roads and tracks and steeplechase). But even when I was training mostly Classic horses, I did not use trot sets as part of my conditioning system. I thought they were outmoded years ago and are even more so in modern eventing. Trot sets do not condition the galloping muscles as well as long walks and cause much more concussion on the horse’s feet and joints, especially on firm ground.


Not Just Any Walk Will Do


But wait—when I say I want you to walk your horse into shape, I need to add a few comments. To me, “walk” does not mean aimlessly ambling around on a loose rein with earphones blasting the latest top-10 hits. It is an interesting phenomenon, when you think about it: People who must make their living by sitting in a cubicle looking at a computer monitor are dreaming of being outside riding. Yet as soon as they get into the saddle, they do the one thing that will separate them from their horse by plugging in their earphones. I disapprove of this because it disconnects you from the natural world just when you want and need it the most. In addition, it is not safe to walk your horse out without being exposed to the same stimuli he is. If you are riding your horse in public with earphones, then you are a menace to society. If you can hear that noisy truck in the distance, on the other hand, you can make sure your horse sees it in plenty of time and that it does not trigger his flight reaction.

Olympic dressage rider and judge Linda Zang says that during a dressage test she wants to see a “going-home walk.” Chances are you will have to use your legs to produce this in your horse, but the effort is worthwhile. Every time your horse’s shoulder moves forward, close your opposite leg in rhythm with the walk that you want rather than the walk he might offer. For example, as his right shoulder moves forward, close your left leg at the girth and then your right leg at the girth as his left shoulder moves forward. When you get off after an hour’s vigorous walk, your legs should be more tired than your horse’s legs. Try to walk on rolling terrain, as it helps strengthen and supple your horse. Whether you are going up or down a slope, make him go straight and maintain a regular rhythm.

For the Record


While the walk is an important tool in your conditioning program, it is not the only tool. Your job is to arrive at your destination event with your horse brought to as high a degree of training as possible. This means that in addition to conditioning, you must schedule adequate dressage, show-jumping and cross-country training. To that end, I want you to keep both a schedule of plans and a work diary. The schedule makes sure that you plan for improvement in every phase from now until the event, while the diary is a record of the work you actually did on a day-to-day basis. For example, your schedule might call for “one-hour walk plus dressage work” (see below for which activity comes first) but your diary says, “shoe off, farrier tomorrow.” Use the schedule to train your horse, but don’t be afraid to change it as circumstances require.

What should a schedule look like? There are as many answers to that question as there are event trainers. My typical schedule does not use a weekly calendar, but rather is what I call a “four-day rotation.” My sample schedule looks like this:

Day 1: Walk and dressage.

Day 2: Walk and show jump.

Day 3: Walk and dressage.

Day 4: Canter (or depending on the level of competition, gallop, once I am getting close to my destination event).

Day 5: Repeat Day 1, and so on.

You can see that there is variety in my schedule, as horses like different activities. I count any cross-country schooling I do as a canter/gallop day. (I also suggest you keep your training diary, as it will be a valuable resource for you in the future. The diary will serve as a guide to the sort of work you have done with your horse in the past and can help you adjust your horse’s workload this season accordingly.)

The next question is, “How much exercise should I give my horse?” The truthful answer is that I have no idea. First you have to tell me what type of horse he is, what level he is currently competing at, what you did with him last season, whether you were happy with the results of your former schedule and so on. Experiment with the sequence of either walk first followed by dressage or dressage first followed by walk. Some horses will go much better if they have walked out first while other horses are quite businesslike and want to get the dressage out of the way and then go for a walk. There is no right or wrong about this, it is just a matter of knowing your horse.

As my training schedule gets close to the destination event, my Novice and Training horses walk for at least half an hour in addition to their technical work, Preliminary horses walk for an hour, Intermediate horses for an hour and a half and Advanced horses for two hours.

I know my conditioning schedule takes more time than others, but I am convinced it produces sounder, fitter horses by making the most of the chance to improve them.