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Bloat - Gastric Dilatation-Volvulus


Gastric dilation/volvulus is a life-threatening disease whereby the stomach balloons (dilation) with gas and may twist (volvulus), resulting in a closure of both the inflow and outflow tracts of the stomach. The swelling (with or without twisting) can block return of blood from the abdomen to the heart resulting in tissue congestion and eventual shock. Widespread tissue damage leads to kidney, respiratory and cardiac failure then death. This condition can affect any breed, but most cases involve older, large, deep-chested dogs. Causes are related to age, diet, activity in approximation to meals or ingestion of large amounts of water. Sign include anorexia, bloat, attempts to vomit, shock and death. Diagnosis is afforded via history, breed and age considerations, physical exam, imaging studies (eg. X-rays), complete blood counts, blood chemistries and laboratory tests. Treatment includes immediate decompression, correction of electrolyte and blood gases abnormalities, cardiac treatment, surgical replacement of proper anatomy, surgical anchoring of the stomach to prevent future displacements and dietary adjustments.

HOW DOES BLOAT HAPPEN?

Scientists have tried for 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 dog 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. 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‚?Ts 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.

Factors Increasing the Risk of Bloating
    Feeding only one meal a day
    Having closely related family members with a history of bloat
    Recent history of boarding or house-sitter caring for dog


There are many injuries and physical disorders that represent life-threatening emergencies. There is only one condition so drastic that it overshadows them all in terms of rapidity of consequences and effort in emergency treatment. This is the gastric dilatation and volvulus - the "bloat."

What Is it and Why Is it so Serious?

The normal stomach sits high in the abdomen and contains a small amount of gas, some mucus, and any food being digested. It undergoes a normal rhythm of contraction, receiving food from the esophagus above, grinding the food, and meting the ground food out to the small intestine at its other end. Normally this proceeds uneventfully except for the occasional burp.

In the bloated stomach, gas and/or food stretches the stomach many times its normal size, causing tremendous abdominal pain. For reasons we do not fully understand, this grossly distended stomach has a tendency to rotate, thus twisting off not only its own blood supply but the only exit routes for the gas inside. Not only is this condition extremely painful but it is also rapidly life threatening. A dog with a bloated, twisted stomach (more scientifically called "Gastric Dilatation and Volvulus") will die in pain in a matter of hours unless drastic steps are taken.

What Are the Risk Factors for Developing Bloat?

Classically, this condition affects dog breeds which are said to be "deep chested," meaning the length of their chest from backbone to sternum is relatively long while the chest width from right to left is narrow. Examples of deep chested breeds would be the Great Dane, Greyhound, and the setter breeds. Still, any dog can bloat, even dachshunds and Chihuahuas.

Classically also, the dog had eaten a large meal and exercised heavily shortly thereafter. Still, we usually do not know why a given dog bloats on an individual basis. No specific diet or dietary ingredient has been proven to be associated with bloat. Some factors found to increase and decrease the risk of bloat are listed below:

Factors Increasing the Risk of Bloating
Feeding only one meal a day
Exercising within a few hours of drinking large amounts of water and feeding a large meal
Having closely related family members with a history of bloat
Eating rapidly
Being thin or underweight
Fearful or anxious temperament
Older dogs (7 - 12 years) were the highest risk group

Factors Decreasing the Risk of Bloat
Inclusion of canned dog food in the diet
Inclusion of table scraps in the diet
Happy or easy-going temperament
Eating 2 or more meals per day

How to Tell if Your Dog Has Bloated

The dog may have an obviously distended stomach especially near the ribs but this is not always evident depending on the dog's body configuration. The exact appearance of the stomach will vary with the degree of twisting, the length of time the dog is bloated, and the anatomy of the dog.


The biggest clue is the vomiting: The pet appears highly nauseated and is retching whitish phlegm or nothing is coming up.

If this is seen, rush your dog to the veterinarian IMMEDIATELY.

What Has to Be Done

There are several steps to saving a bloated dogs life. Part of the problem is that all steps should be done at the same time and as quickly as possible.

First: The Stomach Must Be Decompressed
The huge stomach is by now pressing on the major blood vessels carrying blood back to the heart. This stops normal circulation and sends the dog into shock. Making matters worse, the stomach tissue is dying because it is stretched too tightly to allow blood circulation through it. There can be no recovery until the stomach is untwisted and the gas released. A stomach tube and stomach pump are generally used for this but sometime surgery is needed to achieve stomach decompression.

Also First: Rapid IV Fluids Must be Given to Reverse the Shock
Intravenous catheters are placed and life-giving fluid solutions are rushed in to replace the blood that cannot get past the bloated stomach to return to the heart. The intense pain associated with this disease causes the heart rate to race at such a high rate that heart failure will result. Medication to resolve the pain is needed if the patient's heart rate is to slow down. Medication for shock, antibiotics and electrolytes are all vital in stabilizing the patient.

Also First: The Heart Rhythm Is Assessed and Stabilized
There is a special very dangerous rhythm problem, called a "premature ventricular contraction" or "pvc," associated with bloat and it must be ruled out. If it is present, intravenous medications are needed to stabilize the rhythm. Since this rhythm problem may not be evident until even the next day continual EKG monitoring may be necessary. Disturbed heart rhythm already present at the beginning of treatment is associated with a 38% mortality rate.

Getting the bloated dog's stomach decompressed and reversing the shock is an adventure in itself but the work is not yet half finished.

Surgery

All bloated dogs, once stable, should have surgery. Without surgery, the damage done inside cannot be assessed or repaired plus bloat may recur at any point, even within the next few hours and the above adventure must be repeated. Surgery, called gastropexy, allows the stomach to be tacked into normal position so that it may never again twist.

Assessment of the internal damage is also very important to recovery. If there is a section of dying tissue on the stomach wall, this must be discovered and removed or the dog will die despite the heroics described above. Also, the spleen, which is located adjacent to the stomach, may twist with the stomach. The spleen may require removal, too.

If the tissue damage is so bad that the spleen or a part of the stomach must be removed, the mortality rate increases significantly.

After the expense and effort of the stomach decompression, it is tempting to forgo the further expense of surgery. However, consider that the next time your dog bloats, you may not be there to catch it in time and there is a significant chance of re-bloating at some point. The best choice is to finish the treatment that has been started and have the abdomen explored.

It is crucially important that owners of big dogs be especially aware of this condition and be prepared for it. Know where to take your dog during overnight or Sunday hours for emergency care. Avoid exercising your dog after a large meal. Know what to watch for. Enjoy the special friendship a large dog provides but at the same time be aware of the large dog's special needs and concerns.


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