The Signs and Symptoms of PPID

Have you ever heard the term \”Cushings\”, and been unsure as to what that means? In reality it is Pituitary Pars Intermedia Dysfunction (PPID). Western Horse Review sat down with Dr. Doug Myers, a veterinarian from Boehringer Ingelheim Canada Ltd, to discuss PPID. PPID is a common condition of aged horses and as we learn more about the care and wellness of geriatric horses, increasing attention is being paid to the role of PPID in their lives.

Myers noted that recent study on PPID has suggested a link between horses and ponies that are afflicated with Equine Metabolic Syndrome (EMS) developing PPID. It is now recommended that all horses with EMS over 10 years old be monitored for the signs of PPID.

These signs can include, but are not limited too, lethargy, loss of skeletal muscle mass, rounding of the abdomen, regional adiposity, abnormal sweating and laminitis.  The confirm PPID and assess the severity of the disease in your equine partner single sample resting Adrenocorticotrophic Hormone (ACTH) testing is required. As with most things in the equine world, horses in the early stages of PPID are more of a challenge to diagnose and confirm. You may exhibit reduced performance, loss of muscle tone, or change of attitude. Other signs can include the horse taking a few weeks longer than normal to shed its winter hair coat.

Myers says, \”In the fall of 2014, Boehringer Ingelheim (Canada) Ltd. embarked on a pilot project to test horses across Canada that their veterinarians suspected PPID. All horses had a single plasma sample run for resting ACTH levels. The majority of these samples were taken in October, 2014. This project as well as the follow up 2015 testing program was done in attempt to assist Canadian veterinarians diagnose PPID suspect horses for the owners. A positive diagnosis of PPID can assist the owner with commencing treatment with Pergolide mesythlate (Prascend- Boehringer Ingelheim (Canada) Ltd.).\”

He continues, \”Of the 98 horses for which ACTH results were available in 2014, 55 (56%) had resting ACTH levels consistent with a diagnosis of PPID. Three horses (3%) had borderline resting ACTH levels (10.4-11.3 pmol/L), and forty horses had normal seasonally-adjusted ACTH concentrations (<10.4 pmol/L). Of the horses with PPID, 10% were less than ≤ 10 years of age.\”

In 2015, the Canada wide PPID testing program was repeated with a total of 200 submissions. Multiple breeds, including pony, pony crosses, quarter horses, warm bloods, thoroughbreds and arabs were involved. Of the 198 horses with ACTH results available, 151 (76 %) had a test result consistent with a PPID diagnosis (> 11.3 pmol/L). Six horses (3 %) had borderline ACTH results (10-4-11.3 pmol/L) and 41 horses (21 %) had levels found to be within a normal seasonally adjusted ACTH concentration (< 10.4 pmol/L). The two highest resting ACTH levels found were both in Miniature horses, 600 and 420 pmol/L respectively. Furthermore, of the horses tested, 65 % were 16 years of age or older, 29 % were between 11-15 years old, and 6 % were 10 years of age or younger.

Veterinarians were asked to state what clinical signs the horse had that made a differential diagnosis of PPID a possibility. Many horses had more than one clinical sign that was indicative of PPID. The most common clinical sign noted was laminitis (often chronic) in 51 reported cases. Hair coat or shedding issues were the second most reported sign accounting for 39 cases. Other clinical signs of note included weight changes (increased or decreased) , lethargy, other causes of lameness and chronic infections.

When Canadian equine veterinarians selected clients horses they suspected may have PPID, they were correct the majority of the time. In 2014, 56 % of the cases selected were positive for PPID based on a resting ACTH submission, while in 2015, 76 % of the horses tested positive for PPID when evaluated using a resting ACTH test.

In summary, subtle changes to your horse\’s appearance could signal something big. But identifying PPID early may help ensure a better quality of life for your horse.