Page 39 - New Mexico Horse Breeder Spring 2018

Treatment
Contact your veterinarian if a horse suddenly has a swollen hind leg. “The typical treatment initially would be to cold hose the leg (to help reduce the pain, swelling and inflammation) and then bandage it to help reduce the edema. Some horses will be so painful, however, that they won’t tolerate having a tight bandage on the leg. 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,” says Mudge.
“The mainstay of treatment is anti- inflammatory medication and antibiotics. Non-steroidal anti-inflammatories like bute
or Banamine would be helpful along with antibiotics. Often, the veterinarian will want to culture a sample of any drainage coming from
the leg or from the wound. Sometimes they will ultrasound the leg and try to find a pocket of fluid to aspirate a sample to culture. This will show which bacteria are involved and enable us to know which antibiotic will be most effective. In an ideal situation, we would get a culture before starting the horse on antibiotics to have the best chance of getting a positive culture. Then we are able to figure out which bacteria are involved.”
Some of the milder cases are relatively easy to manage and monitor on the farm with pain medication and antibiotics—especially if the owner is comfortable doing the cold hosing or hydrotherapy, giving medications and doing some of the bandaging. “There are horses that are so painful that they need to be managed in a hospital with more continuous or higher- powered pain medications. Some horses may become systemically ill from this infection. 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,” she says.
Prognosis
The prognosis will depend on several things. Early treatment can reduce the risks for long- term problems. “In various reports, and in my experience as well, if a horse gets to a stage where there is laminitis, either in the limb with the cellulitis or in the supporting leg because it had to bear most of the weight, there is a more guarded prognosis. The ones with systemic illness—sick and with persistent fever—also have a more guarded prognosis,” says Mudge.
“Recent reports give survival rates of 65%
up to 90%. The prognosis is generally better in the cases where there’s a known injury, such as
a laceration or some kind of trauma, or if the cellulitis is related to a surgical procedure. 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,” she says.
One of the biggest frustrations of cellulitis is that some of the worst cases are the ones
in which you never know exactly what set
it off. “Sometimes in a horse that had some
dermatitis, or if we find a small scratch, we suspect that was what set it off, but there are many horses that have mild dermatitis or lots of cuts and scrapes that never develop cellulitis.”
“It seems that the earlier and more aggressive you are with treatment up front, getting the pain and swelling resolved quickly and the infection under control, the better the horse will do. If we see really good progress within the first couple days of therapy, those horses tend to have a better chance to avoid some of the longer term effects like contralateral limb laminitis or chronic lymphangitis—which can be a sequela of cellulitis,” says Mudge. So, don’t wait around; call your veterinarian.
“I warn owners that even when the horses respond well, they may end up with a leg that
is slightly bigger than the other one. Even if everything goes well and the horse makes it through and recovers without residual lameness, there may be some limb enlargement. The horses that get over cellulitis usually don’t have lameness (they end up being comfortable and sound), but they may have a little bit of extra thickening in that leg. It is yet to be determined whether or not prolonged bandaging or using things like compression cold therapy (such as Game Ready) 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,” she says.
An episode of acute cellulitis can be scary enough that a person is usually thankful that they still have a functional horse after the recovery, and might not worry about simple cosmetics. “I’ve had horses referred to me for suspicion of fractured leg because the limb is so swollen and painful. To discover that it’s cellulitis instead of a fracture seems a lot better.
“Cold therapy can be a good way to reduce the heat and potentially some of the swelling.”
Lymphangitis or Cellulitis?
These two types of “swollen leg” can be different, or related, depending on the case. “Cellulitis may affect the lymphatics and create inflammation, slowing down the lymphatic return of fluid,” says Mudge. This can create the edema and swelling.
“Probably the more proper term would be septic cellulitis, meaning
a bacterial infection under the skin, versus a lymphangitis, which is inflammation of the lymphatics. Often the terms are used interchangeably, although chronic lymphangitis usually refers to a sterile edema with no infection. It can become a bit confusing and complicated, however, because there are types of lymphangitis that are associated with infectious agents. But usually when we are using this term, we refer to just the edema and lack of lymphatic return, versus cellulitis (infection).”
Usually in the chronic lymphangitis cases the leg is enlarged, but not as warm nor as painful. The horse isn’t actually lame. He may move a little stiffly just because of the swelling, but there is no pain from the swelling itself.
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