thumb|X-ray of a dog with GDV. The "double bubble" pattern indicates that stomach torsion has occurred.
thumb|X-ray from the underside of a dog with GDV. The dark area is the buildup of gas.
Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs and rarely cats and guinea pigs, With surgery, the mortality rate is 15 to 33 percent.
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 producing any vomitus (nonproductive vomiting). Many dogs with GDV have cardiac arrhythmias (40% in one study). Chronic GDV in dogs, include symptoms such as loss of appetite, vomiting, and weight loss. Hypovolaemia may occur and in severe cases hypovolaemic shock and hypoperfusion.
Hypergastrinaemia has been hypothesised as a cause of GDV. Pyloric hypertrophy as a result of hypergastrinaemia was presumed to cause pyloric outflow obstruction, retarding gastric emptying. Studies have not found evidence to support this theory.
Impairment of gastric myoelectricity retarding gastric emptying has been hypothesised as a cause of GDV. Currently no study has identified an association between gastric myoelectricity and GDV.
Other risk factors include: nasal mite infection; gastrointestinal disease;
The breeds most likely to develop GDV are the Great Dane (10 times more likely), Weimaraner (4.6) St Bernard (4.2) and the Irish Setter (3.5). which has led to the Great Dane being the focus of investigations into causes and risk factors for GDV. Further studies have associated these alleles with greater diversity in the gut microbiome and an increased risk of GDV.
GDV has been reported across the age range in dogs. It is more likely to occur in older dogs but is not a geriatric disease and the risk plateaus after the first 2–4 years for large dogs. Eating only once daily and eating food consisting of particles less than in size also has been shown increase the risk of GDV. One study looking at the ingredients of dry dog food found that while neither grains, soy, nor animal proteins increased risk of bloat, foods containing an increased amount of added oils or fats do increase the risk, possibly owing to delayed emptying of the stomach.
Pathophysiology
The exact pathophysiology is not understood. It is still unknown what order the condition occurs: whether dilatation or volvulus occurs first. Rotations of up to 360° have been reported but typically rotations stop around 270°. 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 the future. While dogs that have had gastropexies still may develop gas distension of the stomach, a significant reduction in recurrence of gastric volvulus is seen. Of 136 dogs that had surgery for gastric dilatation-volvulus, six that did have gastropexies had a recurrence, while 74 (54.5%) of those without the additional surgery recurred. Gastropexies are also performed prophylactically in dogs considered to be at high risk of GDV, including dogs with previous episodes or with gastrointestinal disease predisposing to GDV, and dogs with a first-order relative (parent or sibling) with a history of it.
Prognosis
thumb|A necrotic spleen removed following splenectomy in a dog with GDV. The black/darker end is where the necrosis has occurred
Immediate treatment is the most important factor in a favorable prognosis. A delay in treatment greater than 6 hours or the presence of peritonitis, sepsis, hypotension, or disseminated intravascular coagulation are negative prognostic indicators. Although "early studies showed mortality rates between 33 and 68% for dogs with GDV," studies from 2007 to 2012 "reported mortality rates between 10 and 26.8%". Mortality rates approach 10 to 40% even with treatment. With prompt treatment and good preoperative stabilization of the patient, mortality is significantly lessened to 10% overall (in a referral setting). Negative prognostic indicators following surgical intervention include postoperative cardiac arrhythmia, splenectomy, or splenectomy with partial gastric resection. A longer time from presentation to surgery was associated with a lower mortality, presumably because these dogs had received more complete preoperative fluid resuscitation, thus were better cardiovascularly stabilized prior to the procedure. In fact, the lifetime risk for a Great Dane to develop GDV has been estimated to be close to 37%. Standard Poodles are also at risk for this health problem, as are Irish Wolfhounds, German Shorthaired Pointers, German Shepherds, and Rhodesian Ridgebacks. Basset Hounds and Dachshunds have the greatest risk for dogs less than .
- In "Dog of Death," an episode of the animated TV series The Simpsons, the family dog Santa's Little Helper develops a "twisted stomach", necessitating surgery.