Gastric Dilatation
Volvulus (GDV), Bloat and Torsion

 

 

 

Ron Hines DVM PhD

 

Gastric dilatation is a life-threatening condition that occurs in mature large dogs. I do not see many of these cases but when I do I have work diligently if I am to save the animal. Another term for the condition is gastric dilatation/volvulus or GDV. Volvulus is a twisting of an organ along its long axis. In this disease, the stomach flips over on itself and expands with trapped swallowed air and fermentation gases. Circulation to the stomach and spleen are cut off to the point where the dog may go into shock and die. A startling finding is that the incidence of bloat has increased by more than 1500% over the past 30 years.

What Is The Cause of GDV?
We are unsure why GDV occurs. Exercise just after or before eating may bring on GDV. We used to think that dogs developed GDV when they ate too much. In this theory, dogs that drank after a meal of dry chow caused the food to rapidly expand. This theory assumed that the enlarged stomach then flipped over during rough exercise. We now know that the actual explanation is not that simple. We also know that GDV is associated with abnormal muscular contractions of the stomach. These, plus the kinks that forms in the stomach’s openings, prevent the dog from belching swallowed air. Lack of normal motility and circulation in the stomach cause the body to become too acidic (metabolic acidosis). We also know that dogs who eat from elevated dishes are more likely to become bloated. Their dishes should always be on the floor.

A recent Purdue University Study shines much light on this perplexing disease. They found that certain factors increased the incidence of GDV. The first and most important factor was age. The older the dog was the more commonly they develop GDV. The second most common factor was having a relative that had developed GDV. This shows that genetics plays a part in the disease. The third factor was feeding the dog in a raised food bowl. Raising the food bowl is often suggested in large breeds that have trouble swallowing. So there may be some linkage between esophageal problems and GDV. There was a 2.7-fold increase in the risk of GDV in dogs that ate dry dog food that contained fat as its most common or first ingredient. The risk of GDV increased 4.2-fold in dogs that ate dry foods containing citric acid when the food was moistened prior to feeding. Dry foods containing meat meal with bone among the first four ingredients significantly decreased GDV risk (53.0%). Approximately 30% of all cases of GDV in this study were attributed to consumption of dry foods containing fat among their first four ingredients, while 32% could be attributed to consumption of owner-moistened dry foods that also contained citric acid. Citric acid in the stomach is conducive to gas formation. So choosing your dog's diet is probably the most important thing you can do to prevent gastric dilatation/volvulus bloat and torsion.

It may also be helpful to withhold water for one hour before meals and three hours after. Dry dog foods swell when they become wet and theoretically, this could swell the stomach. If you feed grains such as rice, be sure they are completely cooked.

How We Diagnosis The Problem:
The condition appears suddenly. Gastric dilatation/volvulus occurs almost always in deep- chested large breeds. Borzoi’s, Setters, Afghans, German Shepherds and Greyhounds are a few of the breeds commonly affected. These dog arrive at the veterinary hospital panting and weak. When the problem is advanced, there is a pronounced swelling on the dog’s lower left side. When I push on the abdomen in this area the tummy is abnormally firm and drum-like. The dogs may attempt to retch and belch but are not successful. They salivate and are restless and in obvious pain and distress. When we x-ray these dogs, the gas-filled stomach is quite apparent. The pressure the enlarged stomach places on the blood vesicles of the abdomen decreases the efficiency of blood circulation through the stomach and spleen leading to depression and shock.
Laboratory examination of the blood confirms metabolic acidosis. It is also common for blood potassium to be low. Low blood potassium affects cardiac rhythm and causes muscle weakness.

As circulation through the stomach is hindered, the stomach wall begins to necrose or die. This liberates many toxic products into the blood stream. These products interfere with normal blood clotting and cause a condition known as disseminated intravascular coagulation (DIC) or clumping of the red blood cells. DIC alone can be fatal.

How We Treat The Problem:
Gastric torsion is a life threatening illness that needs to be dealt with quickly. To fight circulatory collapse, I immediately place a catheter into the large vein of the arm for easy access. Then I administer large volumes of intravenous salt solutions with bicarbonate at a rather rapid rate. I monitor the dog’s body weight and urine flow so as not to flood the lungs with fluid.
I also give these dogs intravenous potassium chloride and corticosteroids (prednisolone, dexamethasone). It is important that pressure within the stomach be quickly removed. Most dogs are so shocky that they need no tranquilizers or anesthetics. I first try to pass a stomach tube through the dog’s mouth and into the stomach to remove the air. Giving them simethicone helps decrease froth and pockets of air. In many cases, the kink in the stomach does not allow the tube to pass. When this is the case I insert a large bore needle called a trochar through the side of the dog and into the stomach or cut down on the stomach and temporarily suture the opening I cut in the stomach to the body wall (see diagram). I give all these dogs large amounts of antibiotics because I must move so rapidly that sterility is compromised. Antibiotics are also necessary to combat the bacteria that proliferate in the stomach and intestinal wall. When I am lucky, the dog’s condition stabilizes when the pressure is removed.

When I think the dog can tolerate surgery it is time to enter the dog’s abdomen and place the stomach and spleen back in their proper positions. Then I perform a procedure called a gastroplexy, which entails sewing the stomach to the inner wall of the abdomen so that it can not shift in the future. If the dog is stable enough, I remove the surface layers of a two inch square area on the left middle surface of the stomach and a similar area on the left body wall and sew the two remaining structures together. If the animal is too weak for me to take the time to do this, I incorporate the stomach section in the body wall incision made to reach the stomach. In these cases I also suture a latex drain tube that leads from the interior of the stomach to the dogs skin and allows fluid and gas to drain. These dogs often have serious heart irregularities, which keep me tense during surgery.

Whether or not the dog survives the surgery depends on the degree of shock and stomach necrosis that has occurred. This in turn depends on how soon the dog was brought to me for treatment. A little more than half the dogs survive. Since we do not understand why this condition occurs it is hard for us to plan a life style and diet for the dog that might prevent reoccurrence. Usually, gastroplexy prevents future episodes from being as severe as the first.

 

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