Windt
im Wald Farm
Geauga County, Northeast Ohio
since 1995
Southern Pines Equine Associates
Case of the Month Case Report:
Gastric Ulcers in the Adult Horse
Author: Dr. Phil Woods DVM, Ph.D., Dip
ACVIM
The topic of equine gastric ulcer syndrome (EGUS) is
one of those "hot" topics in equine medicine, and has led to significant
benefits for the health of the horse while posing as many questions
as answers! While population studies have shown some startling results,
for example in comparing EGUS in racehorses and pleasure horses for
example, the significance of gastric ulcers in the individual horse
can be difficult to evaluate.
Causes: EGUS is associated with all the things that cause ulcers in
humans including psychological and physical stressors (e.g. race training,
long distance transportation, un-natural housing conditions, surgery),
medications (e.g. anti-inflammatory drugs such as phenylbutazone and
corticosteroids), and underlying diseases (e.g. pleuropneumonia, lameness).
There is no strong support at this time for an infectious agent such
as Helicobacter pylori being associated with EGUS. It has always impressed
me that this is an equine disease caused by humans!
The numbers: Epidemiologic studies of different populations of horses
has been very useful in identifying factors that predispose to formation
of gastric ulcers. If one compares racehorses to pleasure horses, up
to 80% of racehorses in active training may have gastric ulcers while
only 35% of pleasure horses will have similar endoscopic findings. Horses
that are held off feed or are fed intermittently appear to have a higher
prevalence of gastric ulcers. The accumulated research highlights the
role of multiple management factors associated with EGUS.
The client's presenting complaint: The world is your oyster; there is
such a wide spectrum of presenting complaints that nothing surprises
me any more! Chronic colic, poor performance, poor body condition, poor
appetite, and behavior changes are the most commonly identified complaints
that horses are presented to us for. All of these are valid client complaints
and the clinical signs may refer directly to EGUS, or, may refer to
a primary disease condition with EGUS as a secondary consequence. The
most common complaint that horses are presented to us at SPEA is that
of poor performance.
The diagnosis: It is necessary to perform an endoscopic examination
of the stomach to physically identify that ulcers are present. I know
of no other practical way to definitively diagnose ulcers in the stomach.
The endoscope needs to be at least 2m long, and preferably 3m long.
At SPEA we use a 3m endoscope because the majority of horses examined
are large warmblood types. Our endoscope is a video-endoscope, and produces
an image on a television screen that is viewed by the clinician and
client as it is seen in the stomach, and can be stored on video-tape
for further analysis.
We have to prepare the horse for evaluation in two ways: 1) The horse
needs to be starved for 18 hours and held off water for 2-3 hours prior
to endoscopy. This is essential to produce maximum emptying of the stomach
to allow examination of all the internal surface of the stomach. 2)
Just prior to the procedure, the horse is heavily sedated to allow easy
and safety of passage of the scope in to the stomach, and to allow inflation
of the stomach to maximize visualization of the internal surface of
the stomach. When we have the scope in the stomach, we may have to remove
excess gastric juices using a suction device in the scope.
The result: The video-endoscope produces a picture of the inside of
the stomach. From the interpretation of that image we can make statements
about the health of the stomach, and in particular about the grade or
degree of ulceration and the anatomic location of the ulcerated areas.
The clinical significance of the interpretation depends upon the severity
of ulcers and their anatomic location. When we analyze our results at
SPEA, we find that most of the horses we scope, after excluding other
clinical problems, have some degree of EGUS, but that most of the horses
have mild, grade 1-2 type ulcers, located at the junction of squamous
mucosa and glandular mucosa, particularly around the lesser curvature
of the stomach.
Treatment: Horses with EGUS are treated in a very similar way to that
of humans with gastric ulcers; 1)medications 2)environmental management.
1) Medications: There are many medications touted for use in the treatment
of EGUS, however, in my opinion, only 2 are practical and truly effective
in the horse, and I will only dwell upon these two. The 2 drugs are
ranitidine (Zantac) and omeprazole (Gastroguard (known as Prilosec in
humans)). Both of these drugs inhibit secretion of acid in the stomach,
and omeprazole is probably the more effective at the job. However...
"the sting in the tail" is that omeprazole is about 5 times as expensive
as ranitidine, with one month's treatment costing about $1200 for omeprazole
and $200-250 for ranitidine.
So which of the 2 medications should be chosen when treating EGUS in
your horse. My guidelines are to medicate according to 1) ulcer severity,
2) current and proposed use of the horse, i.e. stress level, and 3)
cost constraints. Therapy is also separated out in to resolution of
ulcers and maintenance of an ulcer-free stomach. In my ideal world all
horses with EGUS would be medicated with omeprazole, it is plainly the
better of the 2 medications. However if the horse is not in heavy training
for a big event, then the use of ranitidine is perfectly acceptable
and much more economic. As a horse moves in to full competition it is
of value to consider omeprazole during transportation and during competition.
2) Management: One area of EGUS that has not been well defined is that
of management of affected horses. Does one keep the horse on anti-ulcer
medications for ever, or can one alter its environment to reduce the
various stressors that are thought to trigger EGUS? We know very little
about this area of disease control, but common sense should tell us
that improving the horse's environment, and altering diet and training
methods will help reduce stress. Certainly some horses may need fairly
continuous medication, and we know that this can be done at a lower
level that that required for initial resolution of the ulcers.
Expectations: So what should you expect subsequent to therapy, and how
do you measure success? Certainly a repeat scoping will tell you whether
or not the ulcers have gone away. However, my major measure of success
is the subsequent performance of the horse, given that most of the horses
we scope are event and racehorses. The results we note are invariably
quite dramatic, with the horse being more athletic, more focused and
keen to compete, and showing a dramatic improvement in appetite and
general demeanor. The real challenge that we have now is to keep this
level of athleticism at its peak by various means. By collaborating
with the veterinarian, the rider gains a new horse with considerable
untapped potential.
