Equine Endocrinology Researchers Revised Guidelines
December 4, 2013
For More Information or to Request a Photo from this News Release, Contact:
Rushmie Nofsinger, Rushmie.Nofsinger@tufts.edu, (508) 839-7910
NORTH GRAFTON, Mass. – Equine pituitary pars intermedia dysfunction (PPID) can
be detected earlier and more reliably with a new set of guidelines developed by
the Equine Endocrinology Group (EEG), a body of leading veterinarians and
researchers in the field of equine endocrinology.
Similar to Cushing’s disease in humans but affecting a different area of the
pituitary gland, PPID is associated with elevated levels of hormones in the
blood. Horses with the condition often have a wide range of clinical signs
depending on the stage of the disease, from loss of energy to muscle wasting,
and the condition is more common in older horses.
The EEG created a set of recommendations in 2011 to help practitioners
identify early versus advanced stages of PPID, and their new recommendations
adjust and refine testing procedures for a more thorough and accurate approach
to diagnosis. Recommendations are based upon published research on PPID.
“Our collective research has shown that horses can often develop this disease
earlier in life, yet earlier clinical signs don't always translate into positive
test results,” said Nicholas Frank, D.V.M, DACVIM, professor and chair of the
Department of Clinical Sciences at the Cummings School of Veterinary Medicine at
Tufts University and group coordinator for the Equine Endocrinology Group. “As
research on PPID advances, we are identifying practical ways to improve early
detection and diagnosis.”
In addition to Dr. Frank, the Equine Endocrinology Group includes Drs. Frank
Andrews (Louisiana State University); Andy Durham (Liphook Equine Hospital);
Dianne McFarlane (Oklahoma State University); and Hal Schott (Michigan State
University).
While the clinical signs of PPID are the same, the recommendations address
changes to the diagnostic process. Previously, horses showing any signs of this
disease were recommended to a undergo one of two tests. One test measures levels
of resting adrenocorticotropin hormone (ACTH) which is produced and secreted by
the pituitary gland. The other is an overnight dexamethasone suppression test
(DST) that causes the production of cortisol to decrease in healthy horses, but
not those with PPID.
The newly established guidelines retain the recommendation to measure resting
ACTH concentrations, but the group has lowered the recommendation for using the
DST. Recent research shows that the DST is no better at detecting PPID than
other tests, and horse owners have concerns about dexamethasone inducing
laminitis, a painful condition affecting the feet that can lead to death.
Instead, the EEG group recommends a thyrotropin-releasing hormone (TRH)
stimulation test, which is particularly useful when horses with early PPID have
normal resting ACTH concentrations. TRH causes the pituitary gland to release
more hormones and ACTH concentrations increase to a higher level in horses with
PPID. This test is easily performed on the farm by taking a baseline blood
sample, injecting TRH intravenously, and collecting a second blood sample 10
minutes later. At present, the TRH stimulation test should only be used between
December and June, which is the only period in which cut-off values have been
established. Cut-off values allow veterinarians to interpret results and
determine whether the horse suffers from PPID.
For more information on the PPID diagnostic guidelines
visit http://sites.tufts.edu/equineendogroup/. Dr. Frank will also discuss these
recommendations at the upcoming American Association of Equine Practitioners
(AAEP) meeting in Nashville, December 7-11.
The EEG meets annually to review diagnosis and treatment recommendations and
discuss research. They also provide advice to veterinarians, specialists,
research scientists, and the public with the mission of increasing awareness of
equine endocrine disorders and improving the diagnosis and management of these
conditions.
To read more,
click here.
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About the Cummings School of Veterinary Medicine at Tufts University
Founded in 1978 in North Grafton, Mass., Cummings School of Veterinary
Medicine at Tufts University is internationally esteemed for academic programs
that impact society and the practice of veterinary medicine; three hospitals and
four clinics that combined log more than 80,000 animal cases each year; and
groundbreaking research that benefits animal, public, and environmental health.