Gastric Dilation – Volvulus Syndrome in Dogs
Gastric dilatation-volvulus syndrome (GDV) is commonly called “gastric torsion” or “bloat”. The first part of the syndrome’s name refers to expansion of the animal’s stomach due to excessive gas accumulation (Dilation). This condition can then be complicated by the stomach twisting around its short axis (Volvulus). Viewed from behind the animal, the stomach can rotate 90-360° in a clockwise direction around the esophagus, which may block the esophagus and prevent the animal from belching or vomiting to release the excess gasses.
The condition is common in domestic animals, particularly dogs. As a consequence of the gastric twisting, a number of emergency conditions can result. These include increasing distension of the stomach, heightened pressure within the abdomen, and damage to the cardiovascular system. Another consequence can be decreased perfusion – the process of moving nutrients around the body via blood in the arteries. Reduced perfusion can result in organ death. In dogs, mortality rates from GDV range from 10 to 60 percent, even with treatment.
Dilation of the stomach and volvulus cause increased pressure on both surrounding organs and blood vessels. The symptoms of GDV therefore include:
• Rapid heart beat (tachycardia)
• Labored breathing (dyspnea)
• Weak pulse
• Pale mucus membranes (nose, gums and mouth)
• General symptoms of shock
• Abdominal pain and distension
• Anxious behavior
• Excessive drooling
• Vomiting (to the point of unproductive dry retching)
CAUSES and RISK FACTORS
The exact causes of GDV are unknown, although several risk factors have been identified.
Genetics and anatomy
Large breeds of dog are at higher risk of GDV, especially deep-chested breeds. The five breeds at greatest risk are Great Danes, St. Bernards, Weimaraners, Gordon Setters, and Irish Setters. The lifetime risk for a Great Dane developing bloat has been estimated to be 37 percent. Other breeds at increased risk include German Shepherds and Standard Poodles.
Dogs having a parent or sibling with a history of GDV are at higher risk and the risk of GDV increases with age, although it has been reported in puppies.
Environmental factors believed to contribute to GDV include ingestion of large amounts of food or water by the dog, ingesting food too quickly, too much activity after eating, or delays in emptying the gastrointestinal system.
Clinical tests for GDV include urine analysis and blood testing for concentrations of lactate in the plasma. Diagnosis may also include imaging techniques such as x-rays of the abdomen.
Other conditions have symptoms similar to those of GDV. These include bacterial infections, gastroenteritis (inflammation of the gastrointestinal tract), or overeating by the dog (sometimes called “food bloat”).
GDV is an emergency condition. Dog’s suffering the condition usually need to be hospitalized to receive aggressive treatment, especially if secondary cardiovascular problems are apparent. After the cardiovascular system has been stabilized, the gastric system can be decompressed. The preferred method is oro-gastric intubation, i.e. insertion of a tube through the dog’s mouth and into the stomach. Surgery can then return internal organs (particularly the stomach and spleen) to their normal positions. To prevent recurrence of GDV, a permanent gastropexy may be required. In this procedure, the dog’s stomach is secured to prevent future twisting.
LIVING AND MANAGEMENT
After an attack of GDV, further treatment is likely to include analgesics and other necessary medications. The dog’s activity should be restricted for approximately 2 weeks, particularly if surgery has been required.
Recurrence of GDV attacks is common, occurring in up to 80 percent of dogs treated medically only, i.e. without surgery. Several steps can be taken to prevent GDV or its recurrence, including:
• Avoiding strenuous exercise by the dog after eating and drinking
• Slowing the dog’s rate of food consumption
• Feeding frequent small portions to the dog rather than infrequent larger portions