- Jun 1, 2008
At the end of the 2005 show season, Jen Gorsuch of Medinah, Ohio, anticipated an uneventful off season for her then-11-year-old Saddlebred mare, Aruba. Unfortunately, that wasn't to be the case. Just one day after having her horse's show shoes removed, Gorsuch noticed that something was very wrong with Aruba's left hind leg.
"We had taken her show shoes off and put her in her stall for the night," Gorsuch recalled. "The next morning, when we took her out of her stall, her leg was swollen from the ankle to the stifle. She'd never stocked up, and she doesn't kick, so we thought she had broken her leg."
Gorsuch didn't know it at the time, but Aruba was exhibiting classic clinical signs of lymphangitis, an inflammation of the lymph vessels that results in lasting effects long after a horse's recovery.
"One of the troubling things about lymphangitis is that we really aren't sure what causes it," says Rose Nolen-Walston, DVM, Dipl. ACVIM, assistant professor of medicine at the University of Pennsylvania's School of Veterinary Medicine at New Bolton Center. "Sometimes owners mistake it for stocking up."
According to Nolen-Walston, lymph vessels, which are part of the lymphatic system, are found throughout the body, like arteries and veins. Lymph fluid--which is squeezed through the body by muscle action--picks up breakdown products from damaged areas in the body and removes toxins along the way. This fluid is filtered through the lymph nodes.
"Arteries bring blood into the lymph system, vessels take fluid out," Nolen-Walston says. "The lymph system is the body's trash collector. When the lymph vessels become inflamed, they pump fluid back into the body. What we think is that the vessels get inflamed and the fluid they should be taking out sits in the tissue."
The result, she says, is the leg swelling that accompanies the condition. Horse owners frequently confuse lymphangitis with stocking up, a condition that also produces swelling in horses' legs, but which is generally caused by stall confinement, overfeeding, and lack of exercise.
"Stocking up usually affects all four legs," Nolen-Walston says. "Lymphangitis typically starts in one leg--usually a rear leg--but can involve both rear legs, and rarely involves a front leg."
The majority of cases are swollen from the hock down or the fetlock down, but sometimes the swelling can be seen as high as the stifle. The lower portion of the leg can be enlarged up to two or three times its normal size, and serum might even seep out of the skin.
Leg swelling is just one way lymphangitis presents itself, Nolen-Walston says. Abscesses in affected legs appear in cases of ulcerative lymphangitis, a condition Nolen-Walston says is more commonly found in horses that live in western regions of the United States.
However, she adds, horses with lymphangitis also run high fevers. That's why owners should immediately investigate further when their horses' hind legs swell.
"Fevers can be quite high--103° to 104º(F)," she says. "Owners should check for fever and call the vet right away."
That's exactly what Gorsuch did. She says her attending veterinarian treated Aruba with diuretics (to help flush toxins from her body) and antibiotics.
"We were lucky that our vet knew immediately what she was looking at," Gorsuch says.
According to Nolen-Walston, veterinarians treat lymphangitis with antibiotics, including penicillin and Baytril (enrofloxin). Banamine and phenylbutazone (Bute) are also prescribed to ease pain and reduce swelling.
Gorsuch's veterinarian also recommended she treat Aruba's legs with cold hosing for the first few days, then alternate cold and hot compress therapy.
"There's no one treatment," Nolen- Walston says. "Some people advocate sweating the leg, cold hosing--all are used with limited success. However, it's important for horses with lymphangitis to get exercise to keep the legs moving and the blood flowing."
Although the antibiotic treatment is straightforward, Nolen-Watson says identifying the cause of a lymphangitis case isn't easy. When Gorsuch discovered Aruba's condition, she looked for the source, but she came up short.
"We looked for a nail in her hoof, for a cut, for a wound, but we couldn't find anything obvious that could have caused an infection," Gorsuch says.
According to Nolen-Walston, it's not unusual for the cause of lymphangitis to be elusive. That's because injuries such as cuts or puncture wounds can be small enough to escape detection.
Even so, she says, the infection generally has lasting effects. Although legs generally return to normal within two weeks after diagnosis and treatment, the condition can recur.
"Some horses never get it again," Nolen-Walston says. "But some horses can have up to two flares a year. And even though the leg returns to normal between flares, it usually remains fatter than the unaffected ones."
According to Gorsuch, the now-15-year-old Aruba has had one lymphangitis flare in the three years since her initial bout, and her affected leg never did return to its normal size. However, she says the condition has not interfered with Aruba's performance.
"We ride her all the time," Gorsuch says. "And she still shows. Occasionally, someone will come up to us at a show and say, 'Did you know your horse's leg was swollen?' But the judges barely notice it."
Nolen-Walston says lymphangitis is frequently seen in horses in their teens. In some severe cases, and in cases left untreated, it can be fatal. Her advice is to treat any leg swelling seriously.
"If a horse displays symptoms, get a look at it, take the horse's temp, and call a vet right away," she advises.
About the Author
Pat Raia is a veteran journalist who enjoys covering equine welfare, industry, and news. In her spare time, she enjoys riding her Tennessee Walking Horse, Sonny.