Gastric Dilatation-Volvulus (GDV), often referred to as "bloat" or gastric torsion," is a serious condition caused by abnormal dilatation and twisting of the stomach. The condition is initiated by abnormal accumulation of air, fluid or foam in the stomach (gastric dilatation). Bloating of the stomach is often related to swallowed air, although food and fluid also can be present. Bloat can occur with or without volvulus, or twisting. As the stomach enlarges, it may rotate 90 degrees to 360 degrees, twisting between its fixed attachments at the esophagus (food tube) and at the duodenum in the upper intestine.
Volvulus can completely obstruct emptying of the stomach. The twist also prevents burping, so the dog cannot obtain relief of air or stomach contents by belching or vomiting. In fact, a hallmark symptom of torsion is nonproductive attempts at vomiting. The bloated stomach obstructs the return of blood from the veins in the abdomen leading to low blood pressure, obstructive shock and associated complications. The dog also may seem short of breath due to pain and the physical compression of the chest and diaphragm caused by the expanding stomach.
The combination of bloating and torsion seriously reduces the blood supply to the stomach (gastric ischemia) and this can lead to necrosis (death) of the stomach wall. Shock and lack of blood supply to abdominal organs break down the integrity of the gastrointestinal tract lining and permit toxins and bacteria to enter the blood stream. Abnormal blood clotting – disseminated intravascular coagulation (DIC) – may develop. The spleen can be damaged or begin to bleed because it is attached to the stomach by a membrane, and it becomes twisted and rotated abnormally as the stomach turns. Heart function is compromised due to lack of venous blood return. Irregular heart rhythms often develop such as ventricular tachycardia. Shock and death follow if the condition is left untreated or if treatment is initiated too late in this devastating sequence.
GDV is most common in deep-chested or large to giant breed dogs between two and ten years of age. GDV can also occur in other breeds, but this is comparably rare. Pure breed dogs are at higher risk for bloat. The breeds most commonly affected include the Great Dane, standard poodle
, Saint Bernard, Gordon setter, Irish setter, Doberman pinscher, Old English sheepdog, Weimaraner, and the Basset hound.
GDV can sometimes be associated with eating or drinking before or after exercise. Risk factors may include once daily feeding and consumption of large amounts of food or water. For more information on risk factors, go to Is Your Dog at Risk for Bloat?