Gastric Dilatation and Volvulus (Bloat)

What causes gastric dilatation and volvulus?

There is not one particular activity that leads to the development of GDV. It appears that it occurs as a combination of events. Studies of the stomach gas that occurs in dilatation have shown that it is similar to the composition of normal room air suggesting that the dilatation occurs as a result of swallowing air. All dogs, and people for that matter, swallow air, but normally we eructate (burp) and release this air and it is not a problem. For some reason that scientists have not yet determined, these dogs that develop bloat do not release this swallowed gas. There is currently several studies looking into what happens physiologically in these dogs that develop GDV.

What are the signs?

The most obvious signs are abdominal distention (swollen belly) and nonproductive vomiting (animal appears to be vomiting, but nothing comes up) and retching. Other signs include restlessness, abdominal pain, and rapid shallow breathing. Profuse salivation may indicate severe pain. If the dog's condition continues to deteriorate, especially if volvulus has occurred, the dog may go into shock and become pale, have a weak pulse, a rapid heart rate, and eventually collapse. A dog with gastric dilatation without volvulus can show all of these signs, but the more severe signs are likely to occur in dogs with both dilatation and volvulus.

How is gastric dilatation and volvulus treated?

When the dog is presented to the hospital his condition is assessed. Blood samples are generally taken and tested to help determine the dog's status. Usually the animal is in shock, or predisposed to it, so intravenous catheters are placed and fluids are administered. Antibiotics and pain relievers may be given.

The stomach is decompressed either by passing a stomach tube or inserting a large needle into the stomach and releasing the gas. After the animal is stabilized, x-rays are taken to help determine whether or not a volvulus is present.

Some dogs with GDV develop a bleeding disorder called disseminated intravascular coagulation (DIC), in which small clots start to develop within the dog's blood vessels. To prevent or treat this condition, heparin is given, if indicated.

The heart rate and rhythm are closely monitored. Some dogs with GDV develop heart arrhythmias, and this is a common cause of death in dogs with GDV. Dogs that already have a heart disease or are prone to heart arrythmias are generally treated with medication.

Once the dog is stabilized, surgery is performed to accomplish three things:

Assess the health of the stomach and surrounding organs. If areas of the stomach or spleen have been irreversibly damaged, they are removed. In such a case, the chances for recovery are very poor, and euthanasia may be an alternative.
Properly reposition the stomach
Suture the stomach in a way to prevent it from twisting again (a procedure called gastropexy). If gastropexy is not performed, 75-80% of dogs will develop GDV again.

After surgery, the dog is closely monitored for several days for signs of infection, heart abnormalities, DIC, stomach ulceration or perforation, and damage to the pancreas or liver. Antibiotics and additional medications may need to be given.

How is gastric dilatation and volvulus prevented?

Despite adopting all of the recommendations listed below, a dog may still develop GDV. Because of the genetic link involved with this disease, prospective pet owners should question if there is a history of GDV in the lineage of any puppy that is from a breed listed as high risk. In addition, the following recommendations should be followed:

Large dogs should be fed two or three times daily, rather than once a day.
Owners of susceptible breeds should be aware of the early signs of bloat.
Owners of susceptible breeds should develop a good working relationship with a local veterinarian in case emergency care is needed.
Water should be available at all times, but should be limited immediately after feeding.
Vigorous exercise, excitement, and stress should be avoided one hour before and two hours after meals.
Some veterinarians recommend the use of elevated feeders for dogs susceptible to bloat.
Diet changes should be made gradually over a period of three to five days.
Susceptible dogs should be fed individually and, if possible in a quiet location.
Dogs that have survived bloat are at an increased risk for future episodes; therefore prophylaxis in the form of preventive surgery or medical management should be discussed with the veterinarian.

Summary

Bloat is a life threatening condition that most commonly affects large-breed, deep-chested dogs over two years of age. Owners of susceptible breeds should be knowledgeable about the signs of the disease, since early and prompt treatment can greatly improve the outcome. By following the preventive measures recommended, pet owners can further reduce the likelihood of their pet developing this devastating problem.

References

Ellison, GW. Gastric dilatation volvulus: An update. Presented at the Western Veterinary Conference, Las Vegas NV, 2004.

Glickman, LT; Glickman, NW; Shellenburg, DB; et al. Multiple risk factors for the GDV syndrome in dogs: A paractitioner/owner case control study. Journal of the American Animal Hospital Association, 1997, 33: 197-204.

Monnett, E. Gastric dilatation volvulus. Presented at the Western Veterinary Conference, Las Vegas NV, 2002.

Simpson, KW. Diseases of the stomach. In Ettinger, SJ; Feldman, EC. Textbook of Veterinary Internal Medicine. W.B. Saunders Co. Philadelphia, PA; 2005: 1319-1321.