Managing Horses With PPID

While no cure exists for PPID, veterinarians aim to reduce clinical signs of the disease using various treatment and management tactics to improve the quality of the horse’s life. The FDA has only approved one drug—pergolide mesylate—to treat PPID. Clinical signs in horses receiving this medication typically improve within one to three months of starting treatment; however, some horses do not respond to this protocol. In addition, if pergolide becomes ineffective or less effective at certain doses, which can happen over time, veterinarians might consider alternative or adjunct therapies such as cyproheptadine and cabergoline. Cyproheptadine is an antihistamine with anti-serotonin properties that can be beneficial when treating conditions involving the pituitary gland, such as PPID. Veterinarians need to continually monitor horses being treated for PPID to evaluate the medication’s efficacy.

Meticulous management helps horses with PPID maintain a healthy weight, which can reduce the severity of clinical signs. These animals typically need a low-nonstructural-carbohydrate (NSC) diet as well as an exercise program (if they can exercise) to maintain a healthy body condition score. The prognosis for PPID horses varies based on the severity of the disease and response to management and treatment; however, early diagnosis plays a vital role in the horse’s long-term health.

Laminitis in PPID Horses

Laminitis ranks as the second most common PPID clinical sign veterinarians observe in horses, after excessive hair growth, and horses with PPID are at least four times more likely to develop laminitis than those without. Laminitis occurs when the lamellae (which suspend the coffin bone within the hoof capsule) become inflamed. In more severe laminitis cases these separate, which can cause the coffin bone to rotate downward and/or sink in the hoof capsule.

Many horse owners do not notice laminitis in the earliest stages, as the lamellae begin to weaken, because most horses do not show clinical signs at this point. As the condition progresses owners might notice their horse appears sensitive when walking on hard ground, has a stronger digital pulse, heat in the hooves, increased heart and/or respiration rate, or is hesitant to walk.

Meet Squash, a Pony with PPID and Laminitis

In 2018 Squash, a now-17-year-old Welsh Pony/Warmblood cross, experienced her first laminitic episode. At that time her owner and veterinarian worked together to manage her conservatively with NSAIDs (non-steroidal anti-inflammatory drugs), regular hoof icing, and stall rest, which proved successful. The veterinarian tested her resting adrenocorticotropin hormone (ACTH) levels, which indicated she had PPID. Due to this diagnosis and concerns about her risk for future laminitic episodes, Squash’s veterinarian prescribed pergolide, which is still part of her PPID management plan.

Squash’s owner also adjusted the mare’s daily routine to help manage her PPID clinical signs and reduce her laminitis risk. She turned her out regularly, but only in a dry lot, exercised her consistently to help her maintain a healthy body condition score (she continued to train for and show in the hunter ring), and kept her on a forage-focused diet with a ration balancer to ensure nutrient requirements were being met without adding excess calories to her diet.

Since the first laminitic episode, Squash has had three more—one in 2021, another in 2023, and the worst one in 2024.

A Case of Acute Onset Laminitis

In February 2024 Jessica Martin, DVM, of Mountain Pointe Equine Veterinary Services, in Hackettstown, New Jersey, responded to a call about Squash, who was exhibiting an acute bilateral forelimb lameness. Squash’s owner suspected the pony was showing early signs of a laminitic episode due to her clinical history. “The (pony) reportedly had previous episodes of laminitis that were managed conservatively and responded to NSAID use quickly,” says Martin. “During this episode Squash was extremely uncomfortable, lying in her stall with an elevated heart rate. This was uncharacteristic of her previous laminitis episodes.”

Over the course of five days, Squash’s owner administered a combination of phenylbutazone and acetaminophen twice each day at Martin’s recommendation, but the mare’s comfort level continued to fluctuate without considerable improvement. “Her owner diligently iced her feet, and the mare wore Soft Ride boots to provide frog and sole support,” says Martin. “We worked closely with her farrier to provide regular trims, decrease her toe length, and improve breakover. Squash was also placed on supplements to manage her metabolic status and encourage weight loss,” in addition to pergolide, which she received before the start of this episode.

Despite Martin and the owner’s efforts, Squash’s lamellar health continued to decline, and radiographs showed separation of the coffin bone from the lamellae, along with rotation. “At this point, her owner was considering euthanasia for concerns of quality of life and long-term soundness,” says Martin.

Despite Martin and the owner’s efforts, Squash’s lamellar health continued to decline. These radiographs showed separation of the coffin bone from the lamellae, along with rotation. | Courtesy Dr. Jessica Martin

Changing Course When Your Treatments Aren’t Working

Experts have reported that laminitis treatment is multifactorial and revolves around treating the underlying condition and stabilizing the structures mechanically, both of which are often not properly addressed. In some cases when these factors are managed properly, and veterinarians still aren’t seeing results, they might try other approaches to help a horse remain comfortable.

In this case Martin, with the owner’s consent, administered Regenaflex-RT, an amnion-derived product via regional limb perfusion in both of Squash’s front feet. “Amnion is a regenerative substance that is harvested from the amniotic sac of mares after foaling and contains growth factors to stimulate healing,” says Martin. “A regional limb perfusion (in this case) involved placing a tourniquet above the fetlock, diluting the product with saline, and injecting it into a vessel, allowing the product to infuse throughout the foot.”

Regional limb perfusions give veterinarians the opportunity to target one focal area with high concentrations of the product. “I had used amnion products in the past but not specifically for this type of case, but the owner and I were willing to give it a try,” says Martin.

Using Amnion Injections

Researchers have established they can use amnion derived products to treat wounds, orthopedic, and soft tissue injuries and diseases in horses. Veterinarians gather the amnion at the time of a live foaling in a sterile procedure and typically preserve them for later use. This collection process poses no risk to the mare or her foal, said Danica Wolkowski, DVM, of Momentum Equine Veterinary Specialists, in Alberta, Canada, during her presentation at the 2023 American Association of Equine Practitioners Convention, held Nov. 29-Dec. 3, in San Diego, California.

“In this scenario, the amniotic membrane, one of the oldest biomaterials used in tissue recovery, is given attention,” she said. “Its use in human skin transplants was first documented by Davis, et al. (1910). Since then, it has gained importance because of its ability to reduce scarring and inflammation, improve wound healing, and aid cell proliferation and differentiation owing to its antimicrobial properties. It is a biomaterial that can be easily obtained, processed, and transported (Niknejad et al. 2008).

“The use of this material in veterinary medicine has already shown good results, as demonstrated in equine ophthalmology by Plummer, et al. (2009) and in cats by Barachetti, et al. (2010),” she added. “Equine membranes have also been used in dogs with good results, as reported by Fahie and Shettko (2007).”

Within 72 hours of this treatment, Squash’s owner reported her condition had significantly improved and her comfort was less reliant on the pain medications. Over the course of several weeks, Martin and her owner weaned the mare off pain medications entirely, and eventually she became sound at the walk. “After placing front shoes, Squash has returned to turnout and even light riding,” notes Martin.

It’s important to note these treatment results were anecdotal, and there is not yet any peer-reviewed, published research into the use of amnion for treating laminitis in horses.

Long-Term Prognosis

While Squash will remain on a protocol of daily pergolide, a low-NSC diet, and exercise to control her weight, manage her PPID, and reduce her risk of future laminitis, Martin says her prognosis is currently open. While PPID can’t be cured, with diligent management many PPID horses—even those with a history of laminitis—can live comfortably and remain in work.

A year after her lamintic episode, Squash is back to full time work and jumping courses. Squash’s owner, Sydney, commented, “I don’t think Squash would be where she is today without Dr. Martin performing the regional limb perfusion with Regenaflex-RT. I was pretty convinced we were going to have to euthanize her. Today, she feels great, and we are even thinking about going to a horse show soon!”

Click here to watch two videos about Squash’s treatment: Before and After.

Written by:

Haylie Kerstetter

Haylie Kerstetter, Digital Editor, holds a degree in equine studies with a concentration in communications and a minor in social media marketing. She is a Pennsylvania native and, as a horse owner herself, has a passion for helping owners provide the best care for their horses. When she is not writing or in the barn, she is spending time with her dog, Clementine.