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Canine Bloat or Gastric Dilatation-Volvulus (GDV) |
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The stomach enlarges
dramatically from gas,
fluid, or both causing the stomach to twist itself, sealing off the
entry and exit of the stomach. 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. The spleen enlarges and causes torsion
of the major vein bringing blood to the heart. Dogs are uually in considerable pain
as they cannot clear trapped gas. Rapid deterioration and death can result.
Immediate relatives of dogs which have suffered from GDV are also
at a greater risk.
A dog with GDV will have a distended abdomen and may appear restless and depressed and have dry heaves. Owners often report that affected dogs were initially observed to be drooling excessively, belching, and making repeated, mostly unsuccessful attempts to vomit. Bloat requires immediate medical attention. It is usually seen in male dogs between 4 and 7 years of age who eat large quantities of dry kibble, exercise vigorously after eating, and drink lots of water after eating. One possible way to prevent bloat is to crate the dog (or keep calm) for at least an hour after eating, feed smaller meals more often and limit the amount of water consumed after exercise. Dogs that gulp food quickly or are stressed are at a greater risk of GDV.
With GDV, owners
need to get the dog to a veterinarian immediately. Successful emergency
treatment involves relieving the pressure within the stomach and treatment
for shock. In most cases, treatment will also involve emergency surgery
to untwist the stomach and "tack" it in place to prevent future reoccurrence
of the stomach twisting,"
Bloat in a dog
Torsion - Fred Lanting
Gastric Dilation Volvulus (canine bloat)
Gastric Dilation Volvulus
Bloat, Torsion, Gastric Dilation-Volvulus (GDV)
Also known as
GASTRIC DILATATION
GASTRIC VOLVULUS
GDV
The x-ray on the right demonstrates the extreme
distension of the stomach that occurs with bloat.
Tail to the left
Head to the right
Bloat in the dog! There are
very few challenges in veterinary medicine that rival an emergency
presentation of bloat in the dog. Known by various terms,
some more accurate than others, a dog with a bloating stomach has
a short time to live without emergency veterinary intervention.
Once the stomach is unable to expel gasses produced from fermentation
within the stomach, a series of events occur that result ultimately
in such intra abdominal pressure that the dog is unable to survive.
Circulatory collapse and heart failure ultimately result, after
extreme stretching of the stomach wall, constriction of intra abdominal
blood vessels, widespread death and destruction of the stomach
wall, and release of intestinal toxins. Let's explore what
is known about canine bloat and actually see an unusual and
relatively uncomplicated case of bloat in a dog.
WHAT IS BLOAT?
Canine bloat occurs when there is gas production
in the stomach and that gas buildup is unable to be expelled
via belching or vomiting, or passed through the intestines and
out of the dog as flatulence. Some bloat cases occur very
rapidly when fermentation of grains in the wet and warm stomach environment
create gas. The influence of grain in creating an environment
conducive to bloat seems even more plausible in that it is very
rare for dogs that consume meat-based diets to develop bloat.
Generally, bloat is the extreme dilation of the stomach as a result
of gas buildup that cannot escape the stomach.
WHAT TYPES OF BLOAT ARE THERE?
GASTRIC DILATATION... is simply the
expansion of the stomach due to the buildup of gas or material
in the stomach.
GASTRIC VOLVULUS (TORSION)...
is the condition where the stomach rotates (flips on
its long axis) and thereby twists the esophagus and small intestine
closed so there is no passage of stomach contents or gas in or
out of the stomach.
HOW DOES BLOAT HAPPEN?
Scientists have tried to decades to learn
about how bloat occurs by setting up bloating conditions in
the laboratory with laboratory dogs... and consistently have
failed in producing the spontaneous bloating that occurs with canine
house pets. The usual history is of a dog of a large breed
that has recently eaten a meal of dry dog food and then exercises
or engages in some physical activity. On occasion, though,
there is no
history of physical activity and the dogs
is suddenly seen trying to retch and vomit unsuccessfully.
The dog paces, becomes uncomfortable, attempts to pass stool
and repeatedly makes retching, gagging noises. Salivation
is common. At this stage it is impossible to determine
what type of bloat is occurring. In the photos above,
the fortunate Malamute had a simple Gastric Dilatation with no torsion
or volvulus. Once the stomach contents and gas were eliminated
via a plastic stomach tube, and the stomach was flushed and antibiotics
administered to prevent further bacterial fermentation and gas production,
the surgery was over and the dog recovered rapidly and successfully.
With Torsion or Volvulus present, far greater damage occurs to internal
blood vessels and stomach tissues, plus the spleen gets caught up in
the twisted mess of tissues and becomes starved for oxygen along with
the stomach. Eventually the heart is affected due to the major
interruptions in blood flow and heart rhythms; plus the pressure
on the heart and diaphragm prevents normal cardio-pulmonary function. When
the blood supply in the abdomen’s major arteries is compromised, blood
flow to the heart and the cardiac output decrease, leading to low blood
pressure, and eventually, shock.
The production of gas in the stomach sometimes
overwhelms the dog's ability to belch it away or pass it through
the bowel as flatulence. There are various theories about
the gastric chemistry that occurs to produce this sudden buildup
of gas. Plus, many dogs that become uncomfortable as the
gas builds up will begin to swallow air, compounding their dangerous
condition.
HOW IS BLOAT TREATED?
Treatment needs to be undertaken immediately.
Time is a very decisive factor in the success or failure of
correcting bloat. Once presented to a veterinarian, a dog
with bloat will become the center of attention and all other activities
at the animal hospital assume a lesser priority. Supportive
medications such as cortisone, antibiotics and intravenous fluids
are started immediately. The veterinarian may need to decompress
the stomach initially (before surgery) by inserting a large diameter
needle into the stomach right through the abdominal wall. An
audible hiss is heard as the gas passes through the needle.
Once this is performed the doctor administers intravenous anesthetic
in very small amounts because the patient in this state of affairs requires
very little intravenous anesthetic to facilitate the passing of the
endotracheal tube through which the gas anesthetic is administered.
Some veterinarians skip the intravenous anesthetic and, via a face
mask, administer gas anesthesia such as Isoflurane... once the patient
is unconscious the endotracheal tube is passed into the trachea to allow
continuous control of anesthesia.
Once anesthesia is at the proper level, a
stomach tube (see the photo above) is gently inserted down the
esophagus in an attempt to gain entry into the stomach.
If there is a Volvulus present and the twisting of the esophagus/stomach
junction prevents passing the stomach tube into the stomach, the
doctor will need to incise the stomach to dissipate the gas and bring
the stomach back to a reasonable state of size and pressure.
If no volvulus (twisting or rotation of the stomach on its axis)
is present such as in the case presented here, with careful and gentle
manipulation by the surgeon within the abdominal cavity the stomach
tube can be directed into the stomach and the gas and stomach contents
can be drained by gravity out of the dog.
Once the intra-gastric pressure is lowered
the presence or absence of rotation of the stomach can be ascertained.
Also, if a volvulus is present, the spleen is also involved and
often its blood supply becomes strangulated. Occasionally,
the doctor will elect to remove the spleen at this time. The
health of the stomach is established... in cases where the gastric
dilatation has been present for hours and the pressure is very high,
the stomach wall will be very thin and stretched
and there may be areas of necrosis (cell death). In
the photos above a well vascularized stomach wall is evident...
that a god situation. In severe bloat where the stomach is
stretched for long periods, the blood supply is shut down and the
stomach wall appears bluish or blackened. This blackish coloration
suggest permanent cell death and damage. Any time there
is necrosis of the stomach wall the prognosis for a successful resolution
of the case is very poor. The massive cell death and absorption
of toxins through the stretched stomach wall creates severe cardiovascular
damage and blood pressure problems. Once a state of shock begins,
the chances of recovery for the patient are slight. Even dogs
that survive surgery and seem to be recovering often succumb to endotoxic
shock hours and even days after the procedure.
When the stomach contents are emptied through
the stomach incision, the stomach wall is finally sutured closed.
If a volvulus is present the surgeon will rotate the stomach
(and spleen) back into the normal anatomical position. Then
the stomach tube is inserted through the mouth into the stomach and
additional flushing and antibiotic administration is done.
Before closing the abdominal incision the surgeon usually will tack
(affix with sutures) the stomach wall against the inner abdominal
wall (actually just inside the rib area) to prevent future episodes
of gastric dilatation/volvulus. This tacking procedure is excellent
insurance against a volvulus happening again.
WHAT CAN BE DONE TO PREVENT BLOAT?
The best suggestions are to feed the dog
two small meals a day instead of one large meal. Do
not allow the dog to drink large quantities of water at one time...
have water available at all times. Do not allow exercise
or other vigorous activity for at least two hours after a full meal.
Feed a diet composed of more meats and less grain.
Below are photos of a dog that had repeat
episodes of gastric dilatation. Luckily, under anesthesia,
a stomach tube was able to be passed and the gas and pressure
was relieved. The stomach was flushed, appropriate medication
was given to help prevent cardiovascular shock, antibiotics were
administered to prevent infection and to eliminate gas forming bacteria
in the stomach. Usually the stomach is sutured or anchored
to the abdominal wall to prevent subsequent bloat episodes.
BREEDS AT MOST RISK...
GDV (the canine bloat) can be
frightening to any dog owner. It can be lethal to dogs, though
many dog owners know very little about it. GDV is a very
dangerous disorder of the canine digestive system. Below is some
information about the disorder and the symptoms that may be helpful
for dog owners. Observation and how well you know your dog’s behavior
is the key. We all must learn to read canine body language because
they can’t express themselves verbally.Section: Overview
Gastric Dilatation-Volvulus (GDV) often referred to as “bloat,” is a serious
condition caused by abnormal dilatation and twisting of the
stomach. The condition is initiated by abnormal accumulation of
air, fluid or foam in the stomach (gastric dilatation). Bloating
of the stomach is often related to swallowed air, although food and
fluid also can be present. Bloat can occur with or without volvulus,
or twisting. As the stomach enlarges, it may rotate 90 degrees to 360
degrees, twisting between its fixed attachments at the esophagus (food
tube) and at the duodenum in the upper intestine.
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This Dog with Bloat has a very hard and Distended
Abdomen |
Volvulus can completely obstruct
emptying of the stomach. The twist also prevents burping, so
the dog cannot obtain relief of air or stomach contents by belching
or vomiting. In fact, a hallmark symptom of torsion is nonproductive
attempts at vomiting.
The bloated stomach obstructs the return of blood
from the veins in the abdomen leading to low blood pressure, obstructive
shock and associated complications. The dog also may seem short
of breath due to pain and the physical compression of the chest and
diaphragm caused by the expanding stomach.
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Radiagraphic
view of Gastric Dilation. The greatly distended stomach
is the black area |
The combination of bloating
and torsion seriously reduces the blood supply to the stomach
(gastric ischemia) and this can lead to necrosis (death) of the
stomach wall. Shock and lack of blood supply to abdominal organs
break down the integrity of the gastrointestinal tract lining and
permit toxins and bacteria to enter the blood stream. Abnormal blood
clotting – disseminated intravascular coagulation (DIC) – may develop.
The spleen can be damaged or begin to bleed because it is attached
to the stomach by a membrane, and it becomes twisted and rotated abnormally
as the stomach turns. Heart function is compromised due to lack of venous
blood return. Irregular heart rhythms often develop such as ventricular
tachycardia. Shock and death follow if the condition is left untreated
or if treatment is initiated too late in this devastating sequence.
GDV is most common in deep chested or large to
giant breed dogs between two and ten years of age. GDV can also
occur in other breeds, but this is comparably rare. GDV can sometimes
be associated with eating or drinking before or after exercise.
What to Watch For
Drooling
Nausea
Restlessness
Abdominal distension
Vomiting leading to nonproductive retching
GDV is life-threatening. See your veterinarian
immediately if you suspect bloat or GDV.
Diagnosis
The diagnosis can usually be made based on the
history and physical examination.
Physical examination should include abdominal
palpation and auscultation of heart and lungs.
After your dog has been stabilized and initial
treatment begun, radiographs may be taken. A lateral abdominal
view in right lateral recumbency with dog lying on the right side,
is the view of choice for differentiation of simple dilatation from
dilatation-volvulus.
After initial stabilization and treatment, a
complete blood count and blood biochemical tests may be performed.
Blood tests help to define concurrent abnormalities that may
influence the choice of anesthesia.
Treatment
Initial treatment of GDV will include emergency
treatment for shock with intravenous fluids, drug therapy, and
decompression of the stomach.
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Placement
of an intravenous cathether for fluid therapy is part of the emergency
treatment. |
Surgery is the recommended treatment
to untwist and stabilize the stomach. To prevent recurrence, the stomach
must be attached to the abdominal wall, known as gastropexy. If the spleen
is badly damaged, it may need to be removed (splenectomy).
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Surgery
is recommended to evaluate the stomach and perform a procedure
to reduce the risk of future occurrences of bloat. This dogs
abdomen is being shaved in preparation for surgery |
Home Care and Prevention
If you observe signs of GDV at home, see your
veterinarian immediately. There is no recommended home therapy
for GDV. Remember that giant-breed and deep-chested dogs are at
increased risk.
Feed small frequent meals and limit water intake
for one hour after eating, and avoid large volumes of water
intake. Limit exercise after eating.
Section: Information In-depth
Gastric dilatation-volvulus (GDV) is a condition
that is centered initially in the stomach, but eventually can
affect the entire body. Some problems that can result are:
Shock and cardiovascular complications
Bleeding disorders
Injured spleen
Secondary infection Heart arrhythmias (irregular
heartbeats. The arrhythmias are caused by poor oxygenation to
the heart (myocardial ischemia), release of toxins, electrolyte
abnormalities, acid-base abnormalities, and gastric receptor stimulation.
These problems can persist even as the GDV is
successfully resolved. Other medical problems can lead to symptoms
similar to those encountered in GDV, and it is important to exclude
these conditions before establishing a definite diagnosis.They
are:
Gastric dilation without volvulus
Aerophagia, which is swallowing air due to difficulty
breathing (dyspnea)
Ascites, or fluid accumulation in the abdomen
Section: Veterinary Care
In-depth
Veterinary care should include diagnostic tests
and subsequent treatment recommendations.
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This
is an intraoperative photo of GDV. The long tubular tissues
are the intestines. The stomach is distended and located
to the left of the intestines. |
Diagnosis In-depth
Diagnostic tests are needed to recognize GDV,
and exclude all other diseases, including:
Complete medical history and physical examination.
Clinical response to gastric decompression (passing a stomach tube or inserting a needle into the abdomen to relieve gas pressure).
Your veterinarian should assess
your pet for shock. It is important to monitor vital signs, airway,
breathing, heart rate and to identify bleeding disorders.
If the diagnosis is not clear, abdominal radiography
(X-rays) is the first diagnostic test performed. An abdominal
X-ray may reveal a large air-filled stomach with a soft tissue
fold that appears to compartmentalize the stomach. This suggests
that the stomach is twisted (volvulus).
After initial stabilization of the patient a
complete blood count (CBC) and blood biochemical test may be
performed. Electrolyte abnormalities may be present.
An electrocardiogram (EKG) is often needed to
monitor for cardiac arrhythmias.
Additional diagnostic tests may be recommended
on an individual pet basis, including:
Arterial blood gas determinations may be needed
to identify complications of shock.
Repeat biochemistries if initial tests are abnormal.
Blood lactate. This test may be prognostic as
a higher level indicates a worse prognosis.
Coagulation studies should be done and fibrinogen
levels should be tested to identify disseminated intravascular
coagulopathy.
Treatment In-depth
Treatments for GDV may include one or more of
the following:
Initial therapy directed at treatment of shock
and alleviation of gastric distension
Rapid administration of intravenous fluids
Administration of flunixin meglumine to decrease
prostaglandin synthesis for shock (controversial)
Monitoring of urine output
Antibiotic therapy to prevent complications of
gastrointestinal injury
Corticosteroids such as methylprednisolone sodium
succinate or dexamethasone to treat endotoxemia and shock
Sedation or anesthesia to perform gastric decompression
and lavage
Decompression is a procedure in which a large,
flexible rubber or plastic tube is passed through the mouth into
the stomach. This is done to relieve pressure and to remove the
stomach's contents. Decompression does relieve gastric dilatation,
but does not correct a volvulus (twisting) if that is also present.
Decompression also decreases pain and discomfort, improves venous
blood return to the heart and helps reduce further injury to the
stomach lining.
Once the tube is placed into the stomach, the
stomach is flushed with warm water to remove fluid and food debris.
This is called gastric lavage.
If the tube does not advance, a procedure called
gastrocentesis may be needed. This procedure involves clipping
hair over the side where the stomach is located and inserting
a needle through the wall and into the stomach to remove air. This
removal of air and pressure will often allow a tube to be inserted.
A temporary pharyngostomy tube, which is a tube
that goes from behind the jaw to the stomach, can be placed if
the dog is too unstable for surgery due to cardiac arrhythmias or
other complications. However, in most cases of GDV, the next step
is abdominal surgery.
Surgery is the definitive treatment for GDV.
While tubing can effectively treat this disease, surgery is
the best treatment and follows shock therapy, gastric decompression
and arrhythmia stabilization.
If volvulus is present, surgery is needed to
return the stomach to its normal position. Surgery should not
be delayed unnecessarily. Surgery is also essential to allow
visual inspection of the stomach wall because this tissue may not
be viable if it has been deprived of blood supply for very long.
During surgery, the stomach is repositioned, the spleen examined (and
untwisted), devitalized (dead) stomach wall can be removed, and the
spleen can be removed if it does not become normal after untwisting.
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This is a
picture of a "gastropexy" in which the stomach has been returned
to its normal position and sutured to the body wall to try and
prevent the reoccurance of "bloat" |
If the patient is stable after
these procedures, a gastropexy is usually performed, which is
a procedure to attach the stomach to the abdominal wall and help
to prevent recurrence of GDV. There are several surgical techniques
for gastropexy such as tube gastropexy, circumcostal gastropexy,
belt loop gastropexy and muscle flap (incisional) gastropexy. Each
of these techniques has proponents. In a comparison between the different
surgical types, all were found to have similar effectivenss. The
tube gastrotomy was found to have the most complications. The best technique
is the one that your veterinarian is familiar with and can perform.
Unfortunately, some dogs suffer extensive injury
to their stomach such that the bulk of muscle is devitalized
or dead, especially if the GDV has been prolonged and care was
not sought quickly. In such cases, euthanasia may be the only course
as removal of the stomach is not a practical option.
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This
is a photo of a compromised stomach. The dark red section
held by the surgeon's right hand is bruised stomach. The spleen
is the dark organ to the right. |
After surgery, post-operative
care by your veterinarian may include:
Monitoring for 2 to 4 days that includes observation
for arrhythmias. Severe arrhythmias may be treated with drug
therapy.
Post-operative pain treatment
Fluid therapy to ensure that an adequate blood
potassium level is maintained
Post-operative wound care
Antibiotics are usually continued. Even with
the sterile procedures employed during surgery, there is the
risk that devitalized stomach tissue or intestine injured by shock
(low blood flow) may allow bacteria to move into the circulation.
Reduction of stomach inflammation can be treated
with cimetidine (Tagamet®) or famotidine (Pepcid®).
Enhancement of gastric motility can be treated
with metoclopramide HCl. Gastric motility is often abnormal post-operatively
due to gastric distension, lack of blood flow to the tissue, and
the surgery itself.
Most dogs that die from complications of GDV
will do so within the first four days post-operatively.
Section: Follow-up
Optimal treatment for your pet requires a combination
of home and professional veterinary care. Administer prescribed
medication as directed and be certain to contact your veterinarian
if you are experiencing problems treating your pet. Observe your
pet's general activity level, appetite, and interest. Keep your pet
in a supervised area of the home.
Antibiotic therapy is usually continued for seven
to ten days. Drug therapy for ventricular arrhythmias (such as
procainamide), is sometimes needed if arrhythmias are very severe.
Feed small frequent meals, often using a bland
diet. Your veterinarian will discuss diet with you. Limit water
intake for one hour after eating and always prevent your pet
from ingesting large volumes of water. Avoid any exercise after
eating.
Re-evaluation by your veterinarian is often recommended
in seven to ten days with suture or staple removal and examination
of the heart rate and rhythm.
| Normal Stomach |
Parts |
|
A
- Pylorus
B - Pyloric Antrum C - Esophagus D - Fundus E - Body F - Omentum |
| Gastric Dilatation with Torsion |
Descriptions |
|
2. Torsion of the esophagus 3. Duodenum displaced to the left. 4. Hemorrhages on the stomach's surface. 5. The Greater Omnetum covers the Stomach's surface. |
| Breed |
GDV Risk Ratio |
Risk Rank |
Breed |
GDV Risk Ratio |
Risk Rank |
| Great Dane |
41.4 |
1 |
Alaskan Malamute |
4.1 |
14 |
| Saint Bernard |
21.8 |
2 |
Chesapeake Bay Retriever |
3.7 |
15 |
| Weimaraner |
19.3 |
3 |
Boxer |
3.7 |
16 |
| Irish Setter |
14.2 |
4 |
Collie |
2.8 |
17 |
| Gordon Setter |
12.3 |
5 |
Labrador Retriever |
2 |
18 |
| Standard Poodle |
8.8 |
6 |
English Springer Spaniel |
2 |
19 |
| Basset Hound |
5.9 |
7 |
Samoyed |
1.6 |
20 |
| Doberman Pinscher |
5.5 |
8 |
Dachshund |
1.6 |
21 |
| Old English Sheepdog |
4.8 |
9 |
Golden Retriever |
1.2 |
22 |
| German Shorthaired Pointer |
4.6 |
10 |
Rottweiler |
1.1 |
23 |
| Newfoundland |
4.4 |
11 |
Mixed |
1.0 |
24 |
| German Shepherd |
4.2 |
12 |
Miniature Poodle |
0.3 |
25 |
| Airedale Terrier |
4.1 |
13 |
| Bloat site |