Pituitary pars intermedia dysfunction, or PPID, has been called ‘equine Cushing’s disease’ by horse owners and veterinarians for years. As more information is learned about it, the clinical signs of PPID are becoming more recognizable in horses. However, there are still several other misconceptions or myths about the disease.
Steve Grubbs, DVM, PhD, DACVIM, equine technical manager for Boehringer Ingelheim Vetmedica, Inc. (BIVI), helps dispel some of the most common misconceptions about PPID.
1. PPID is only a condition of the geriatric horse.
“This is probably one of the most common myths about PPID,” Grubbs said. “We have been tracking epidemiological information on horses diagnosed with PPID, and have found that PPID affects horses of all breeds, and all ages, even as young as 5 years old.”
Grubbs added that it is important to monitor all horses for clinical signs of PPID. “Horse owners should perform frequent overall health checks looking for early signs of PPID. If you have concerns, consult your veterinarian. The earlier the diagnosis, the better,” he said.
2. Decreased athletic performance is not a clinical sign of PPID.
One of the earliest signs of PPID, horses showing decreased athletic performance and/or lethargy, could have an endocrine issue like PPID. Grubbs said, “Catching PPID early on can have a profound impact on how the horse responds to treatment before other signs appear.”
3. The overnight dexamethasone suppression test is the gold standard for the diagnosis of PPID.
Once considered the best way to diagnose PPID, the overnight dexamethasone suppression test is no longer recommended by experts to test for PPID. “Instead we recommend using the resting adrenocorticotropin hormone (ACTH) concentration test,” Grubbs said. “It is a simple blood test that your veterinarian can draw at any time during the day.”
4. Generalized hypertrichosis, or long hair all over the body, is the earliest clinical sign to use for diagnosing PPID.
“Generalized hypertrichosis considered an advanced sign of PPID. “Early signs of PPID include regional hypertrichosis or patchy spots of long hair, delayed hair coat shedding, lethargy, decreased athletic performance and laminitis,” Grubbs said.
5. Signs of lameness, like tendon laxity and suspensory desmitis are not associated with PPID.
While laminitis a well-known sign of PPID, until recently other signs of lameness have not been considered to be indicators of the disease. However, new research is indicating that other causes of lameness, particularly certain tendon issues and suspensory desmitis, may also be associated with horses with PPID.
6. For PPID diagnosis, resting ACTH cannot be used in the autumn time period.
The resting ACTH concentration test can be used at any time of the year when you utilize seasonally-adjusted reference ranges. “The resting ACTH test is a simple blood test that your veterinarian can draw at any time,” Grubbs said. “The benefits to using this test include not only for diagnosis but also to monitor ACTH levels to know if treatment is working to decrease the levels.”
7. Horses can have only one endocrine disease, either PPID or equine metabolic syndrome (EMS), but not both at the same time.
The diagnostic laboratory at Cornell University has amassed more than 3,000 samples to test for PPID from the IDPPID study. “Of those horses diagnosed with PPID, we found that 47 percent also had increased plasma insulin, which is an indication of EMS,” Grubbs said.
For more information on PPID, including the early and advanced signs, visit www.idppid.com. For information on Prascend (pergolide mesylate tablets), the only FDA-approved treatment for PPID, contact your veterinarian or visit www.prascend.com. (Important safety information: PRASCEND is for use in horses only. Treatment with PRASCEND may cause loss of appetite. Most cases are mild. Weight loss, lack of energy, and behavioral changes also may be observed. If severe, a temporary dose reduction may be necessary. PRASCEND has not been evaluated in breeding, pregnant, or lactating horses and may interfere with reproductive hormones in these horses. PRASCEND Tablets should not be crushed due to the potential for increased human exposure.)
About Boehringer Ingelheim Vetmedica, Inc.: Boehringer Ingelheim Vetmedica, Inc., (BIVI) develops, manufactures and markets novel and innovative solutions for the prevention and treatment of disease in the cattle, equine, pet and swine markets. BIVI is the fifth largest animal health company in the U.S. and is a part of the global Boehringer Ingelheim Animal Health GmbH. With more than 3,800 employees worldwide, Boehringer Ingelheim Animal Health achieved net sales of about 1.4 billion euros in 2015. Boehringer Ingelheim continually invests more than 11 percent of net sales of the animal health business in R&D. For more information, visit www.bi-vetmedica.com.