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LAMINITIS - continued from part 1.

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SHOULD I EXERCISE THE HORSE?

• No forced exercise - in the short term (acute). Do not exercise a horse which is showing any signs of pain.
• Allow free exercise - have the horse is a large area at least 20’x20’ with a soft surface and shade. Make access to feed and water easy. Provide company close by.
• Yes hand walking - carefully, in the longer term (chronic). Only if the horse is free of pain.
• Preferably, allow only self exercise in the first 30 days.

During the acute stage of laminitis exercise was once thought to be beneficial; however, there is already a great increase in blood flow to the foot during the acute stage and the tissues which are bonding the insensitive and sensitive laminae are very fragile and easily weakened. Exercise causes further tearing of the remaining laminae and increases the damage. Ideally the horse should be in an area big enough for it to move around if it wants to. A normal stable is too small as standing stock still is also not ideal. Inflammation is part of the repair process and although it is necessary to minimise the pain and inflammation in the short term once the acute stage has passed it is possible to minimise or eliminate anti-inflammatory drugs from the horses treatment and reintroduce some controlled exercise such as walking in hand. Exercise increases blood flow and metabolism by the cells so that healing progresses. Balanced trimming and shoeing are very important factors in increasing the horses comfort and returning blood flow to the affected parts of the foot through movement. Depending upon the severity of the laminitis a horse may return to normal activities in 30 days in very mild cases and several months to one year or more in the most severe cases. Some never return to being 100% sound. The time is entirely dependant upon the individual case and response to treatment.

 

SURFACES FOR LAMINITIC HORSES

The ideal bedding surface is soft and loose, without packing into the feet; e.g., sand (must be shaded), rice hulls or wood shavings. These surfaces encourage the horse to lie down and rest, to
"Take a load off the feet". If the horse is progressing well in a sand yard, leave it there. When sand is slightly damp it conforms to the sole of the foot, this may increase frog pressure which is known to enhance circulation to the toe via anastimoses between blood vessel and delivers it via an alternate blood supply to the affected areas. Damp sand is cooling and this is important during the acute stage. If sand is heated it will exacerbate the problem. On soft surfaces, a sore horse will position its feet for comfort, angle and pressure over the frog and sole. If sand is not available many horses respond to padding and protection of the sole (if not excessive). Too much packing causes sole pressure. Compressible, dense foam is ideal. Laminitis causes varying degrees of sinking of the pedal bone lower into the hoof capsule and dropped/convex sole. Avoid walking the horse over, or standing the horse on, surfaces which will cause sole pressure. Make a mound in the centre and let the horse sort its own hoof angles out.

THE FARRIER/SHOEING

Shoes are a positive option, not a necessity in all cases. They combine well with sand as bedding. Most horses which have failed to improve begin to if the feet are protected or shod with supportive bar shoes.

• Since writing this section I avoid packing feet entirely. I get the best surface for the horse I can. I will cover the feet, protect the sole, Use compressible packing to medicate exposed sensitive sole and fit shoes etc., but I avoid any form of packing leading to sole pressure that the horse cannot get relief from and that includes commercial sole packs of any kind.
• A large sheet of H-grade polystyrene is really handy for standing the horse on while your are working.
• If the horse is able to be shod and will benefit from it, protect the sole of the weight-bearing foot during shoeing. Stand the horse on dense foam, which helps prevent sinking and tearing of the laminae at the toe and crushing of the circumflex artery (during the acute stage).
• Open toe bar shoes, egg bar shoes and English bar shoes, commercially made therapeutic bar shoes specific for laminitis are available. One advantage of the open toe bar shoe when correctly fitted is that no pressure is applied to the wall at the toe. This means no pressure is transferred to the laminae and none to the coronary band. For chronic cases and ponies I have found that this shoe gives an increased weight bearing surface area behind the widest part of the foot and relieves all pressure from the toe allowing for resection of the laminitic wedge.
• For acute cases my first choice is a bar shoe that can form the basis of a hospital plate, so that the sole can be supported without excess pressure of any kind, frog pressure can be accurately increased and the soles are protected. Filling the whole sole with very soft foam soaked in betadine is often enough. I do not like any form of firm setting hoof reconstruction products, not even the flexible ones. In my experience they lead to too much pressure.
• If the wall is very soft and weakened the feet may collapse onto the shoe and the wall will distort. I have found that one of the best ways to deal with this is removing the shoes and making adjustments to maximise contact with the outer edge of any hardened laminae and solid wall and to let the feet harden as much as possible. Often by this stage it is leading into Summer and therefore I use the dry weather to my advantage and encourage the owners to keep the horses feet away from moisture. The harder and dryer they are the better the weak laminae are at transferring force to the limb without collapsing.
• In chronic cases where the hoof has become distorted or if the sole is convex (normal is concave) there may be a lot of sole pressure and pain. Relieve this by removing excess built up sole and use foam to stand on, so the horse has less pain or is pain free before spending a lot of time working on one foot. The horse will be a lot easier to work with if you take the time to do this.
• Make sure the hind feet are comfortable as these are now the primary weight bearers.
• The sole is extremely sensitive to pressure from mud, stones and badly fitted shoes.
• Seating out the inner border of the shoe to prevent sole pressure is essential.
• Most cases require only front shoes if the horse is on a soft surface.
• The shoe must offer maximum posterior support (shoe length). Egg bar, straight bar, English bar shoes and set under toe bar shoes or reverse shoes are all suitable. In effect, the shoe is modified to suit the individual. Freedom from sole pressure, ease of breakover (the toe is set under or bevelled or both) and posterior support are the key features.
• The hoof pastern angle must be normal, not broken forward or broken back. A suitable surface will allow the horse to choose an adjusted angle if raising the heel increases comfort.
• The frog can help support body weight. Frog pressure can be achieved with padding, bar shoes or padding combined with hospital plates, hoof construction materials etc. This method allows for easy adjustment if the horse shows signs of discomfort and immediate removal of pressure when no longer required.
• Frog pressure has some benefits on circulation to the toe. It activates the pathway (anastimose) from the dorsal digital artery to the circumflex digital artery near the heel, bringing blood around to the toe by an alternative route. This is very beneficial in keeping damaged tissues at the solar border supplied with fresh blood. However, excess pressure can be worse than none at all. Judge the response to alterations and decrease or remove the pressure if a negative response is produced. This is a key reason I prefer hospital plates which allow for as much adjustment as needed.
• Cover exposed sensitive tissues with sugardine swabs, treat as an open wound, combine with a hospital plate or bandaging and change regularly. House the horse in a clean, dry area.
• Fill space between sole and plates or pads with sugardine or some other form of soft, antiseptic dressing and foam.
• If there are signs of sub-solar fluid build up or infection in the wall on X-ray, or laminitis is severe drainage should be established at the toe. Remove an inverted V-shape section of anterior wall (toe) to the level of the sensitive sole. In severe cases, the wall and sole will drain a large amount of serum immediately, giving relief. Treat as an open wound; use sugardine swabs and bandage.
• Do not remove sole during the first 30 - 40 days other than to relieve sole pressure. Exposed sensitive sole will form granulation tissue, requiring treatment to discourage it.
• The wall can be thinned across the toe (anterior wall) to just outside the insensitive laminae. This may relieve pressure over the laminae and distal phalanx. This is not a severe resection, does not bleed and none of the sensitive structures are exposed. It is thought to allow more flexibility of the wall and allows for some swelling.
• Resection of the laminitic wedge can be performed when the horse’s condition has stabilised (6 weeks or longer). This does not expose the sensitive laminae or remove the wall at the coronary band over the toe and will still offer good regrowth without the risks associated with resection up to the coronary band.
• Should you raise the heels? I think the only way to answer that is to place a wedge under the heel of the dressed hoof and see what the animal does. If you do it to one foot and it begins to take more load on it, then go ahead. However, if you raise the heels and wedge the foot and fill the sole with filler and the horse is not better. You have made it worse.  Raise the heel < 15° only when you can demonstrate a benefit. I have seen a few horses much worse after this has been done. I don’t do it. I enocurage a mound and a soft surface and let the horse sort it out itself.
• If the horse is not better with farriery changes in less than 24 hour reassess them carefully and make adjustments if necessary, small details matter at this stage.
• A 30 day shoeing schedule will make it easier to reduce distortion and keep the hooves in balance. Never go more than 6 weeks between farrier visits.
• Remove nails individually with nail pullers - this reduces pressure and damage to the hoof.
• If the horse was recovering well and the shoeing was successful, then a week or 2 later the client rings and says the horse/pony has gone lame again and they suspect a problem with the shoeing. Be diligent in checking every detail of your work. The space for sole pressure may have filled with dirt causing pressure, the wall may be collapsing onto the shoe, unshod patients may have worn all the wall away because they were running about and feeling good. Then they get sole pressure and go foot sore, some have gut pain and inappetance from the drug therapy used to treat the pain which is then a cause of more laminitis or confused with foot pain. This is the time when horses may experience their next bout of laminitis because e.g., the horse was going really good so we put her out in the paddock for a while or, I didn’t think a few days without the supplements would make any difference, or I started to put her back on her old feed because she has lost so much weight, or I let my child ride it yesterday. You need to discuss the whole lifestyle because laminitis relapses due to these types of issues are common.

NAILING

In severe cases the reaction may be extreme so veterinary assistance with nerve blocks and sedatives may be required. However older well educated horses usually allow you to shoe them the first time without much trouble. Constantly picking up sore feet makes the horse resentful. If a horse is comfortable and recovering in its living area leave it alone, you can still check the hoof temperature, pulse and coronary band etc., without picking up feet. The opposite applies if there is a risk of sole pressure due to the bedding packing into the feet. In these cases cleaning the sole out 2 - 3 times per day is the minimum. At the second shoeing, the horse may expect it to hurt and therefore misbehave. Tapping vibration causes pain. As the laminitis improves, so should behaviour. Use smaller, thinner nails. Avoid the toe area and drive the minimum number of nails (4 - 6). Tap gently, with rhythm and don’t try and tighten them right down. When nailed with care many acutely laminitic horses do not react badly. Glue on shoes and hoof reconstruction compounds are options.

WHAT TO DO FOR THE FIRST WEEK

The laminitic equine is fragile. Therefore, these are “the rules”.

• Within the first 48 hours the horse or pony will still benefit from cold and ice water therapy. Use ice baths as much as possible (ice should never be used directly on the skin). After 48 hours they may begin to resist and I take this as a sign that it is no longer beneficial.
• The surface must be sand or very soft e.g., shavings so that it can easily dig its toes into it. If you can’t make a hole by shuffling your own toes it is too hard.
• The pony or horse must have shade and the feet and whole animal should be kept cool in warm weather over 18°C. The hotter the patient the longer the recovery! Only rug at night or in cool weather. If necessary create shade where the horse wants to be. In very cold weather keep the patient comfortably warm with 1 - 2 rugs - never hot.
• Feeding oaten hay and small mixed feeds is important and the more often it is done the better, therefore 4 small feeds + supplements + hay per day are the minimum (see below).
• Feeding the suggested supplements e.g., antacids to a laminitic animal that does not like them and will not eat them defeats their purpose. Therefore, mix them into a paste and squirt this into the mouth or add a little molasses to the mix or delete them completely until the patient is eating. Don’t wait more than an hour or two to see if the patient will eat it. If no - start again. Therefore, no matter how much I believe in the benefits of these ingredients in the diet it is more important to have roughage in their gut at all times. Get the laminitic patient to eat fibre.
• Stick to the no grain diet, use other tasty treats to get it to eat e.g., a few grated carrots.
• A pony that is not eating is likely to have pain. If there are signs of pain ask the vet to check the horse for colic or worsening of the laminitis. Colic may cause laminitis, may follow laminitis, may be due to the treatments for laminitis or is concurrent with laminitis because the horse isn’t eating. The horse’s foot pain may have decreased the appetite and it is important to break the cycle by managing the pain effectively.
• Therefore, Try ice bathing the feet and then offer some food and monitor the dose of NSAIDs carefully.
• While you having any further conversation with your vet ask about treatment for prevention of ulcers and gastritis and how best to minimise the dose of NSAIDs and pain management.
• If the patient is not receiving antibiotics, probiotics can be given to help repopulate the caecum and colon with beneficial bacteria species.
• Take the feed and water to the pony.
• Place the feed at knee height, this takes some of the weight bearing off the front legs. Feed time is a good time to ice bath as well.
• Don’t put anything in the water that tastes funny! Keep it close and keep it clean.
• Ice bath the feet for as long as there is any signs of pain and heat. During the first few days I suggest every 2 - 3 hours during the day. Continue while are acute signs, heat, pain, swelling etc.
• DMSO roll on can be applied very sparingly every day while the acute symptoms persist. It is absorbed immediately and will get into the system despite the water baths.
• Check with your vet before combining NSAIDs such as Phenylbutazone, DMSO, Flunixin,  etc. These drugs work synergistically and the side effects from their combined actions are worse than that of any single drug.
• Do not change anything if the laminitic patient is getting better. If its not broken “don’t fix it”.
• Do not separate the patient from its mates. Provide company, this is a good incentive to eat and be happy.
• What else can you do to make the patient comfortable?
• When everything is stabilised and the patient is free of pain. Wait another 30 days before moving the horse off sand. Maintain the diet indefinitely.
• Like all medical situations good nursing leads to rapid recovery.

Advice to the owner from the vet and farrier - If we do not hear from you we often assume that all is well. If there is no improvement, please tell your vet and farrier “not everyone else”.
If the horse has pain, please “call the vet”. Ask lots of questions, research widely and seek second opinions only from those who are qualified to give them. I encourage you to get as much information as you can. We must all learn from each experience and every laminitic horse is unique. Please keep us informed. If you get a second opinion that is beneficial to the situation, convey the advice, even if you have to write a letter so that your vet and farrier may learn from it as well. Then they may go on to offer better service to other people in the future.

INFECTION

Infection is harder to prevent and treat in areas of poor blood supply and dead tissue. It can be an ongoing  problem in cases of laminitis, acute and chronic, leading to recurring abscesses and occasionally infection of the pedal bone (infective osteitis/osteomyelitis). Bone infection can eventually lead to the horse being euthanased unless it is treated aggressively as early as possible, even then the prognosis is guarded. Preventing infections and seedy toe in the chronic foot requires regular trimming and good hygiene.

THE LAMINITIC WEDGE - HOW IT AFFECTS THE FOOT

An area of dead tissue, bruised and damaged sensitive and insensitive laminae, forming rapidly after the acute phase of laminitis. Cells in the damaged area die off, while cells on the edges of the afflicted area are inflamed and produce a wound secretion. This is combined with an over production of weakly keratinised cells growing off the sensitive laminae to form the wedge.  Mechanical tearing caused by a long toe and movement increases the problem. Depending upon the severity of the laminitic episode the affected wall may grow down with minimal long term effect or stay as a wide fibrous white line (laminitic wedge) which distorts the hoof angles. Thick wall/laminitic wedge at the toe must be rasped back at each shoeing to restore a normal hoof/pastern angle. A severe laminitic wedge can cause pressure on the distal phalanx, leading to devitalisation and reabsorption of bone. The wedge is the ideal place for bacteria to breed, leading to infections and seedy toe. Seedy toe is the most common secondary effect of neglected laminitic feet. It can underrun more than a third of the wall and decreases the attached surface area even further. It needs to be resected and in some cases the hoof may require a partial or complete reconstruction to restore function. In the long term, wall resection may help normalise hoof growth, function and appearance. It is easier to prevent seedy toe with regular farriery than it is to treat the consequences. Infections and seedy-toe are both worse in neglected feet, wet weather and dirty conditions.

When there are signs of consistent improvement and the horse can be shod. Only remove 30% of the wall, straight across the toe. The resection needs to be trimmed back every three weeks as it continues to keratinise, forming a hard outer layer. If not regularly removed the keratinised layer forces the new wall over it, making the resection unsuccessful. .

X-RAYS, DISTAL PHALANX POSITION AND ROTATION

X-rays are a valuable diagnostic tool. They tell us whether or not the distal phalanx is sinking lower into the hoof capsule, they show the positions of the wall and pedal bone, the thickness of sole and indicate whether there is fluid, infection or gas forming in the soft tissue space. Many people describe the pedal bone as rotated. X-rays during the acute phase often show the pedal bone against the angles created by a flared and distorted hoof capsule. This can be misleading when assessing for rotation or sinking. The term rotation creates panic and scares many owners unnecessarily. They expect the pedal bone to drop through the sole at any moment. Rotation is defined as a state of being pivoted around an axis. The axis in this case is the distal interphalangeal (coffin joint). The phalanx bones are normally all at the same angle. When the heel is raised or the toe is shortened this angle is broken forward at the coffin joint and the pedal bone appears to have rotated around its pivot point at the center of the joint. I have described true cases of rotation in the section on club feet as this is what a rotated pedal bone is. Therefore rotation is incorrectly described if the pastern bones are in normal alignment, or the hoof is distorted with a laminitic wedge or if the heel is long or toe is short and these imbalances have not been corrected for with farriery before the radiograph is taken. When x-rays are taken, the hoof pastern angle should be normal and the hoof in a normal weight-bearing position; i.e., trim the foot if necessary, as laminitis does not always strike a neatly balanced foot. If the wall at the toe  is chronically flared the top 1/4 is still usually in a normal alignment and forms a guide to trim the rest off from the front. The excess heel is judged with experience. Then an accurate x-ray of the pedal bone and the hoof capsule is achieved. If an x-ray is taken of a chronic laminitic foot while it is non weight bearing and the hoof is untrimmed, then another x-ray is taken after addressing these problems the difference is dramatic. In these cases I doubt that any rotation truly exists other than that created by a lack of good farrier. Long term changes to the distal phalanx associated with long term neglected laminitis include a curling upward of the pedal bone around its edges (pixie toe), pedal osteitis, remodelling of the distal phalanx e.g., the solar surface flattens. Even these feet with a correctly trimmed hoof capsule will appear dramatically better when re-radiographed.
Occasionally very flat feet with a long toe/low heel laminitic feet are allowed to develop a severely broken back hoof/pastern angle. This increases the tearing forces on the damaged laminae at the toe. This is prevented by good, regular farriery. Normal hoof angles at all stages of the treatment of laminitis essential.

After the acute stage, the rapidly forming laminitic wedge exaggerates the forces affecting the wall at the toe, forcing it away from the pedal bone which is now repositioned within the capsule which has moved around it. The deep digital flexor tendon plays only a small part in this effect and most rotated x-rays are produced from chronic feet with excess heel or short toe or a flared toe and wide laminitic wedge. In other words, the hoof capsule is distorted more than the bone structure. This could be described as counter rotation of the pliable hoof capsule, while the phalanx bones are in normal alignment. True rotation does occur, but cannot be accurately by using the distorted hoof capsule as a guide. The first step is always to normalise the hoof as much as possible.

The hoof is still held in place all the way around the back, in most cases, by the laminitic attachment of the lateral cartilages and bars, and the pedal bone within the hoof is attached to the deep digital flexor tendon at the back and extensor tendons at the front. Consider the relative heights of the coronary band and extensor process on x-ray and the alignment of the phalanx bones, rather than using a distorted hoof capsule as a guide. This has more diagnostic relevance than "rotation" when the hoof capsule is distorted.

THE CRIPPLE

Several severe laminitic episodes, months or years apart, can lead to chronic degeneration of the distal phalanx, circumflex artery and the cells producing the wall, white line and sole. Tension on the deep digital flexor tendon due to muscle spasm as a cause or effect of pain can lead to a broken forward hoof pastern angle and chronic rotation of the pedal bone. Severing the tendon (desmotomy) gives short term relief but research has shown that most do not progress well for more than a year or so. Therefore why not investigate alternative therapies including nutrition, acupuncture, massage, trigger point therapy, physiotherapy and stretching combined with farriery. Management of the feet becomes a complex problem involving many environmental factors. It can be difficult to maintain quality of life. Some horses never return to a totally pain-free existence. Many cope with this, functioning as valuable stud animals. Others never respond sufficiently to therapy and should be euthanased on humanitarian grounds. The principles are the same no matter how chronic or severe distortion of the feet has become. Trim for normal hoof/pastern angles and heel length within the capabilities of the damaged or contracted structures; shoe for maximum posterior support and avoid sole pressure. Hoof reconstruction may aid your ability to shoe the hoof as required to normalise it. Use the diet as fuel to promote health and grow health hoof without letting the patient gain excess weight. Do everything possible to restore normal hoof growth and function. The feed bin motivates most horses who have survived this long. They eat everything and have a great desire to live. Successful treatment of laminitis requires long-term treatment of the whole horse, not just the feet. It is a long, slow process. Vets or farriers who are unsure of what to do next, or have a patient which is failing to improve, should seek a second or third opinion. Sharing information with the owner or carers is important. Well informed people make better decisions.

PROGNOSIS

The symptoms of laminitis may be mild and last for less than 1 - 2 days and often the horse will return to normal activity in weeks with few if any chronic effects. If the symptoms are initially severe and decrease steadily over 2 - 4 days or even a week or more, then a return to normal soundness may take months. Acutely painful feet for more than a week can lead to a very long recovery. The aim is steady improvement in soundness and no setbacks. There are no two horses with laminitis which are exactly the same. Horses with mild symptoms may surprise you with the severity of the hoof changes. Therefore, the best advice I can give you on likely outcomes is the longer and more severe the clinical signs are, the slower the recovery and the less likely the horse is to be sound in the short term. After 2 or 3 annual episodes of laminitis some horses are never 100% sound. I recommend that while you have an acute case in your care that you think in months not weeks, so that you do not get disappointed. It will take 8 - 12 months to regrow the hoof completely so that the crisis line (the groove in the hoof where the laminitis occurred) should serve as a time guide. When this line is more than a third of the way down the wall there should be significant improvement and therapeutic farriery should restore normal hoof shape and angles. Steady improvement is a good sign. Intermittent or ongoing lameness is a bad sign and should prompt you to talk to your farrier and vet. At this time reassess all factors including daily management, feeding etc. For most owners laminitis is a big learning curve and a few setbacks may occur.

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