Deep-chested dogs are susceptible to gastric torsion; the dreaded "bloat"
Introduction Bloat, Torsion :
Gastric dilatation-volvulus (GDV). Call it what you will, this is a serious, life-threatening condition of large breed dogs. While the diagnosis is simple, the pathological changes in the dog's body make treatment complicated, expensive, and not always successful. A typical scenario starts with a large, deep-chested dog, usually fed once daily. Typical breeds affected are Akita, Great Dane, German Shepherd, St. Bernard, Irish Wolfhound, and Irish Setter. Sighthounds, Doberman Pinschers, Weimaraners, Bloodhounds, other similar breeds, and large, deep-chested mixed breeds are also affected. Factor in the habit of bolting food, gulping air, or drinking large amounts of water immediately after eating to this feeding schedule and body type. Then add vigorous exercise after a full meal, and you have the recipe for bloat. Of course, the fact that not all bloats happen in just the same way and the thought that some bloodlines are more at risk than others further complicates the issue. Simple gastric distention can occur in any breed or age of dog and is common in young puppies who overeat. This is sometimes referred to as pre-bloat by laymen. Belching of gas or vomiting food usually relieves the problem. If this condition occurs more than once in a predisposed breed, the veterinarian might discuss methods to prevent bloat, such as feeding smaller meals or giving Reglan (metoclopramide) to encourage stomach emptying. Some veterinarians recommend, and some owners request, prophylactic surgery to anchor the stomach in place before the torsion occurs in dogs who have experienced one or more bouts of distention or in dogs whose close relatives have had GDV.
The physiology of bloat :
Torsion or volvulus are terms to describe the twisting of the stomach after gastric distention occurs. The different terms are used to define the twisting whether it occurs on the longitudinal axis (torsion) or the mesenteric axis (volvulus). Most people use the terms interchangeably, and the type of twist has no bearing on the prognosis or treatment. When torsion occurs, the esophagus is closed off, limiting the dog's ability to relieve distention by vomiting or belching. Often the spleen becomes entrapped as well, and its blood supply is cut off. Now a complex chain of physiologic events begins. The blood return to the heart decreases, cardiac output decreases, and cardiac arrythmias may follow. Toxins build up in the dying stomach lining. The liver, pancreas, and upper small bowel may also be compromised. Shock from low blood pressure and endotoxins rapidly develops. Sometimes the stomach ruptures, leading to peritonitis. Abdominal distention, salivating, and retching are the hallmark signs of GDV. Other signs may include restlessness, depression, lethargy, anorexia, weakness, or a rapid heart rate.
GDV is a true emergency. If you know or even suspect your dog has bloat, immediately call your veterinarian or emergency service. Do not attempt home treatment. Do take the time to call ahead.; while you are transporting the dog, the hospital staff can prepare for your arrival. Do not insist on accompanying your dog to the treatment area. Well-meaning owners are an impediment to efficient care. Someone will be out to answer your questions as soon as possible, but for now, have faith in you veterinarian and wait. Initial diagnosis may include x-rays, an ECG, and blood tests, but treatment will probably be started before the test results are in. The first step is to treat shock with IV fluids and steroids. Antibiotics and anti-arrythmics may also be started now. Then the veterinarian will attempt to decompress the stomach by passing a stomach tube. If this is successful, a gastric lavage may be instituted to wash out accumulated food, gastric juices, or other stomach contents. In some cases, decompression is accomplished by placing large-bore needles or a trochar through the skin and muscle and directly into the stomach. In some cases, this medical therapy is sufficient. However, in many cases, surgery is required to save the dog. Once the dog's condition is stabilised, surgery to correct the stomach twist, remove any unhealthy tissue, and anchor the stomach in place is performed. The gastroplexy, or anchoring surgery, is an important procedure to prevent recurrence, and many variations exist. Your veterinarian will do the procedure he feels comfortable with and which has the best success rate. Recovery is prolonged, sometimes requiring hospital stays of a week or more. Post-operative care depends on the severity of the disease and the treatment methods employed and may include a special diet, drugs to promote gastric emptying, and routine wound management.
Clearly, prevention of GDV is preferable to treatment. In susceptible breeds, feed two or three meals daily and discourage rapid eating. Do not allow exercise for two hours after a meal. As previously mentioned, some owners feel that certain bloodlines are at greater risk and choose to have gastroplexy performed as a prophylactic measure. While the genetics of GDV are not completely worked out, most breeders and veterinarians feel there is some degree of hereditary. Therefore, while prophylactic gastroplexy will probably help an individual dog, it makes sense not to breed dogs who are affected or who are close relatives of those suffering from GDV.
Kathleen R. Hutton, DVM