Bloat - Gastric torsion

Bloat, also known as torsion, gastric torsion, and gastric dilatation-volvulus (GDV) is a medical condition in which the stomach becomes overstretched by excessive gas content. The name comes from the Middle English blout, meaning soft or puffed, which is from the Old Norse blautr, meaning soft or soaked. Meteorism, its name derived from the writings of Hippocrates, is now rarely used in English. The condition occurs most commonly in domesticated animals, especially dogs and cattle, but rarely in cats. In dogs gas accumulation in the stomach may cause or be caused by a volvulus, or twisting, of the stomach which prevents gas from escaping. Deep-chested breeds are especially at risk. Mortality rates in dogs range from 10 to 60 percent, even with treatment. With surgery, the mortality rate is 15 to 33 percent.

Causes
Bloat in dogs is likely caused by a multitude of factors, but in all cases the immediate prerequisite is a dysfunction of the sphincter between the esophagus and stomach and an obstruction of outflow through the pylorus. Some of the more widely acknowledged factors for developing bloat include increased age, breed, having a deep and narrow chest, stress, eating foods such as kibble that expand in the stomach, overfeeding, and other causes of gastrointestinal disease and distress. Studies have indicated that the risk of bloat in dogs perceived as happy by their owners is decreased, and increased in dogs perceived as fearful. This may be due to the physiological effects of the dog's personality on the function and motility of the gastrointestinal system. Dogs with inflammatory bowel disease may be at an increased risk for bloat.

Dietary factors
One common recommendation in the past has been to raise the food bowl of the dog when it eats. However, studies have shown that this may actually increase the risk of bloat. Eating only once daily and eating food consisting of particles less than 30 mm in size also may increase the risk of bloat.One study looking at the ingredients of dry dog food found that while neither increased grains, soy, or animal proteins increased risk of bloat, foods containing an increased amount of added oils or fats do increase the risk, possibly due to delayed emptying of the stomach.

Breed susceptibility
The five breeds at greatest risk are Great Danes, Weimaraners, St. Bernards, Gordon Setters, and Irish Setters.In fact, the lifetime risk for a Great Dane to develop bloat has been estimated to be close to 37 percent. Standard Poodles are also at risk for this health problem. Basset Hounds have the greatest risk for dogs less than 23 kg.

Symptoms
Symptoms are not necessarily distinguishable from other kinds of distress. A dog might stand uncomfortably and seem to be in extreme discomfort for no apparent reason. Other possible symptoms include firm distension of the abdomen, weakness, depression, difficulty breathing, hypersalivation, and retching without vomiting. A high rate of dogs with bloat have cardiac arrhythmias (40 percent in one study). Chronic bloat may occur in dogs, symptoms of which include loss of appetite, vomiting, and weight loss.

Treatment
Bloat is an emergency medical condition: having the animal examined by a veterinarian is imperative. Bloat can become fatal within a matter of minutes.

Prevention and reduction of recurrence
Recurrence of bloat attacks can be a problem, occurring in up to 80 percent of dogs treated medically only (without surgery). To prevent recurrence, at the same time the bloat is treated surgically, a right-side gastropexy is often performed, which by a variety of methods firmly attaches the stomach wall to the body wall, to prevent it from twisting inside the abdominal cavity in future. While dogs that have had gastropexies still may develop gas distension of the stomach, there is a significant reduction in recurrence of gastric volvulus. One study showed that out of 136 dogs that had surgery for bloat, 4.3 percent of those that did have gastropexies had a recurrence, while 54.5 percent of those without the additional surgery recurred. Gastropexies are also performed prophylactically in dogs considered to be at high risk of bloat, including dogs with previous episodes of bloat or with gastrointestinal disease predisposing to bloat, and dogs with a first order relative (parent or sibling) with a history of bloat.

Precautions that are likely to help prevent bloat include feeding small meals throughout the day instead of one big meal and not exercising immediately before or after a meal.