Gastric Bloat and Torsion:  Deadly

When signs of this condition appear, immediate treatment is critically important

If you own a deep-chested dog — a Newfoundland or Great Dane, for example — you should be aware of a condition known as gastric bloat and torsion. Among all canine disorders requiring emergency treatment, it is among the most common, and one of the deadliest.

Also called gastric dilatation-volvulus (GDV), its signs are usually unmistakable, and immediate veterinary attention is always needed in order to save a stricken animal's life. An estimated 25 percent to 40 percent of GDV patients die for lack of emergency veterinary care within six to 12 hours following its onset.

Unrelieved Pressure

Gastric bloat is the severe expansion (dilatation) of the stomach, typically after a large meal that is followed by the eager consumption of water and, frequendy, a period of strenuous exercise. The inflation of the stomach is caused when a combination of food, liquid and air intake that blends with normal digestive secretions, yielding an intolerably high amount of gas and abdominal pressure. Torsion occurs as the distended stomach proceeds to twist upon itself. When the stomach twists more than 180 degrees on its long axis, the condition is called volvulus.

The buildup of gastric gas would normally be relieved by burping, while an excess of undigested food in the stomach would be relieved by vomiting. But when the stomach twists, sphincters that control the opening and closing of two vitally important passageways into and out of the stomach are closed off — one leading from the esophagus to the stomach, the other leading from the lower end of the stomach to the small intestine.

Consequently, a dog's attempt to belch, vomit or defecate the gastric contents will be unproductive, and the stomach will become increasingly distended with gas. When this occurs digestion ceases, causing die accumulation of fermenting food and accompanying bacteria in the stomach.

The greatly distended stomach compresses blood vessels in the abdomen and within the stomach wall. The resulting lack of blood the stomach wall can result in tissue death (necrosis) unless treated prompdy. Also, the bacteria that proliferate in the stomach can pass into the animal's bloodstream, and the compression of the great vessels in the abdomen may impede blood flow to the heart, causing the dog to go into shock.

Meanwhile, if the oxygen supply to the stomach and nearby organs - including the spleen and pancreas - is not restored quickly and the bloating continues, the ongoing deterioradon of the stomach wall will proceed rapidly, and die stomach may rupture. Within a short/period — a few hours or so — the suffering dog may die from a combination of factors: tissue damage, a ruptured stomach, kidney failure, respiratory insufficiency, cardiac failure and shock.

Warning Signals

Although the pattern of consuming a large meal followed by the excessive con- sumption of water and a period of vigorous exercise can be regarded as the "classic event" precipitating GDV, the condition may also occur for unknown reasons. And the tendency is for its onset to become evident in the middle of the night. "We rarely see this happening during the day," says Dr. Flanders, an associate professor of clinical sciences at Cornell University's College of Veterinary Medicine. "It almost always occurs in the wee hours of the morning. Owners are awakened by the sound of their dog retching or pacing around. If they feel the dog's abdomen, they'll notice that it's very tense, very hard, and getting larger by the minute. There is really nothing that the owner can do — or should do — except get the animal to a veterinarian right away."

The earliest signs of gastric bloat typically include general anxiety — restlessness, pacing and whimpering. The animal will show no interest in water or food. On the contrary, it may begin drooling heavily, retching, and trying to vomit, but without success.

Within a short period, the dog's abdomen will become visibly swollen and it will start to breathe rapidly and pant in distress. Tapping on the abdomen will produce a hollow, drumlike sound. The dog will probably lie down, and it will not respond to efforts to get it back on its feet. The animal's gum tissue and other mucous membranes may become pale, and its heart will beat rapidly.

"If the dog seems to be uncomfortable but looks relatively bright to the owner," says Dr. Flanders, "that's a much better sign than if the animal can barely get around or is recumbent."

In either case, it's likely that serious bloating is occurring, and the stomach may already be twisted or starting to twist. The nearest veterinary clinic should be notified that the animal is on its way and to be prepared to admit a dog with gastric bloat and possible torsion.

Emergency Treatment

At the clinic. Dr. Flanders explains, the veterinarian will first treat the animal for shock, by giving it fluids intravenously. Then a tube — about the diameter of a garden hose — will be inserted into the animal's mouth and gently fed into its stomach. "The idea is to draw the gas out of the stomach through this tube," he says, "and if the stomach is not twisted, this will usually work. We'll also put fluid down die tube to lubricate food and odier material that's in the stomach and try to draw that out, too."

In some instances, he adds, a stomach that has already begun to twist may "de- rotate" on its own, once excess gas has been released through a tube or suctioned out through a percutaneous needle. "But what usually happens," says Dr. Flanders, "is that decompression of the stomach works only temporarily because the dog will inhale more air, which will mix with the fermentable products in the stomach. More gas will then form, and the torsion will not be relieved. So in most cases, once the stomach twists, surgery is needed to untwist it."

Treating Torsion

An X-ray may be taken to confirm the gastric torsion, but a veterinarian may not want to waste valuable time when the condition is clearly apparent. Dr. Flanders describes the procedure: "The dog will be anesthetized, and the surgeon will go in and untwist the stomach by hand, back to its normal position. If it looks healthy, wonderful! But if it's been twisted for a long enough period of time, portions of the stomach tissue may have necrosed [died], and any dead sections must be removed.

After that, we want to make sure that the stomach can never twist again. So then we do what's called a gastroplexy. In that procedure, we suture part of the stomach to the abdominal wall so that, if the stomach bloats again — which is not unlikely — it will be prevented from twisting."

The surgery is risky because it is an emergency procedure that must be done on a severely compromised patient, Dr. Flanders notes. In dogs with necrotic stomachs, he says, the mortality rate is about 70 percent. But even for animals with healthy stomach tissue, the mortality rate is about 30 percent. On a brighter note, animals that survive an attack of GDV and the ensuing operation can go home after a few days and, with proper post-operative rest, can be back to normal within a few weeks.

Preventive Measures

The risk of gastric bloat can be greatly reduced by feeding a large dog two or three small meals a day, rather than one large meal. The dog should not be allowed to consume large amounts of water or engage in strenuous exercise for at least two hours following a meal.

Another preventive measure is prophylactic gastroplexy, a procedure in which the stomach of a puppy or young dog is sutured to the abdominal wall at the same time as another procedure is being done such as spaying or neutering. The latest advance in preventing GDV, says Dr. Flanders, is the laparoscopic performance of prophylactic gastroplexy — a procedure that requires much smaller surgical incisions.

In addition to Great Danes and Newfoundlands, Dr. James Flanders identifies German shepherds, greyhounds, Saint Bernards, Labradors and Irish wolfhounds as being breeds most frequenty experiencing GDV. Although smaller animals with comparatively elongated abdominal areas — such as dachshunds, basset hounds and cocker spaniels — are also at elevated risk, he estimates that 90 percent or more of those afflicted are large- or medium-sized dogs.

While a distended stomach may afflict puppies of any breed that overeat, a young dog's inflated stomach is likely to be relieved by belching excessive gas or vomiting excessive food. As a result, torsion and volvulus are extremely rare in young canines.

By Tom Ewing