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CANINE BLOAT
What
is “Bloat" in
the dog?
Bloat is general term denoting a condition
in which a dog’s stomach swells with fluid and gas and
then usually goes on
to twist on its long axis. It is also known as “Gastric Dilation”
or "Gastric Dilatation/Volvulus Syndrome," or more
simply, “GDV.” Dilatation means that the stomach is distended
with gas, but it is still located in the abdomen in its correct
place. Volvulus means that the distention is associated with
a twisting of the stomach on its longitudinal axis. Left
untreated, GDV rapidly leads to shock and death.
Cause
The true cause of GDV remains unclear. It is known that
GDV tends to affect mainly large, deep-chested dogs. There
is no apparent age or gender predilection, but the incidence
of the condition does tend to increases with age. It is most
common in dogs 7-10 yr old. A heritable, familial predisposition
may exist. Doberman Pinschers, German Shepherds, Great Danes,
Gordon Setters, Irish Setters, Saint Bernard’s, and Standard
Poodles are at greatest risk. An association between GDV
and inflammatory bowel disease has been suggested by some,
but this remains unproven.
Regardless of the initialing cause, swelling of the stomach
with swallowed air, intestinal gas and fluid most likely
precedes twisting of the stomach. Distention of the stomach
by gas and fluid may be associated with air gulping (aerophagia),
diffusion of dissolved gas from the bloodstream, release
of carbon dioxide after the reaction of stomach acids with
certain substrates, or bacterial fermentation. As the stomach
swells and twists, gastric outflow becomes obstructed, resulting
in even more swelling and twisting.
Diagnosis
A tentative diagnosis is often possible on the basis of the
pet’s recent history and a physical examination. Occasionally,
affected dogs will have a history of a recent ingestion
of a large meal followed by exercise. Owners often report
that affected dogs were initially observed to be drooling
excessively, belching, and making repeated, mostly unsuccessful
attempts to vomit.
As the condition progresses, abdominal
distension becomes increasingly obvious. An enlarged stomach
will cause the
body wall to protrude prominently, especially on the dog's
left side. The swelling will be very firm and increasingly
obvious. Affected dogs are usually in some degree of pain
or very depressed. They may lie in what is commonly called
a "praying position" with the front legs drawn
fully forward. Dogs not in shock may appear anxious
Abdominal radiographs (x-rays) of bloated dogs often show
classic and unmistakable findings and are useful in finalizing
the diagnosis. Blood tests show abnormalities consistent
with shock, metabolic acidosis, blood clotting abnormalities,
muscle damage, kidney damage and inflammation.
Treatment
Bloat is a life threatening emergency. The condition will
not self-correct and there is no effective home treatment.
Affected dogs should be examined and treated by a veterinarian
immediately. The initial goals of veterinary treatment are
to stabilize the patient, prevent or lessen shock, and decompress
the stomach.
Initial management for shock should include the administration
of IV fluids and perhaps corticosteroids. Antibiotics are
often given to combat secondary sepsis. Additional medications
may be required.
Metabolic acidosis frequently accompanies GDV. Adequate
fluid therapy and gastric decompression generally correct
this problem. Electrolyte abnormalities should be addressed
if present.
Gastric decompression should be accomplished as soon as
possible. Initially, an attempt should be made to pass a
well-lubricated stomach tube. If successful, this will permit
venting of built up excess stomach gas. Successful passage
of a stomach tube does not rule out concurrent gastric volvulus.
Once the stomach tube enters the stomach, gastric gas readily
escapes. Excess fluid and ingesta are removed via gravity
and suction. After the stomach has been decompressed, it
is usually flushed with warm water or saline to remove any
remaining debris.
If a stomach tube cannot be readily passed into the stomach,
which is often the case with GDV, excess gas may be relieved
by inserting a large-bore (16-18 gauge) "over the
needle" catheter, into the bloated stomach, directly
through the skin. Once excess gas escapes, it may be possible
to pass a stomach tube and flush the stomach as previously
described.
Definitive treatment of bloat requires surgery. The goals
of surgery are to un-twist the stomach, remove the excessive
stomach gas and fluid, reposition the stomach, and anchor
the stomach to the body wall to prevent future recurrence
of GDV. This surgery is inherently risky, because of the
affected dog’s deteriorating condition.
During surgery the stomach wall must be inspected for areas
that may have lost its blood supply. Although this is a very
bad prognostic sign, the devitalized area(s) of the stomach
should be surgically removed.
The decompressed and de-rotated stomach must be anchored
to the inside of abdominal wall - in a procedure called a
gastropexy - to prevent recurrence of GDV. This procedure
greatly reduces the likelihood of recurrence.
Abnormalities in the rhythm of the heart (arrhythmias) must
also be diagnosed and treated. Severe arrhythmias can become
life-threatening at the time of surgery and for several days
after surgery. An electrocardiogram (ECG) is the best method
for monitoring the heart's rhythm.
According to the scientific literature, the survival rate
for dogs with GDV varies between 10-60%. The survival rate
for dogs that undergo treatment may be largely be determined
by the severity of the stomach distention, the degree of
shock, how quickly treatment is begun, and the presence of
other diseases, especially those involving the heart. Most
dogs that do die of GDV (70%) do so within the first 4 days
after surgery. Many dogs develop ventricular arrhythmias.
Cardiac arrhythmias associated with GDV are often difficult
to control
Prevention
One of the most effective means of preventing GDV is prophylactic
gastropexy - the surgical attachment of the stomach to the
inside of the body wall. Anchoring the stomach to the inside
of the body wall does not prevent gastric dilation (swelling
with gas and fluid), but it should lessen its severity and
it should prevent a swollen stomach from twisting on itself.
Gastropexy has been shown to reduce the risk of recurrence
of GDV by about 92% following a first episode and we would
expect that it should be at least as effective when performed
on dogs at high risk of GDV before they ever experience GDV.
At
Chastain Veterinary Medical Group, prophylactic gastropexy
can now be performed laparoscopicly
for dogs
at risk of
bloating.
Performing the procedure using
a laparoscope results in only 2 small incisions! Anesthesia
time is short, pain is minimal, and recovery is rapid.
Owners of high-risk dog breeds should consider discussing
this option
with their veterinarian.
Dogs with a tendency to develop GDV – whether or not they
have had a gastropexy - should be fed smaller meals more
frequently over the course of the day. Excessive exercise
should be avoided to decrease the likelihood of volvulus,
and consumption of large volumes of water after exercise
should be avoided to limit gastric distention.
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