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Gastric Dilatation and Volvulus (GDV; “Bloat”)

juil. 30, 2018

Gastric dilatation and volvulus (GDV) is also referred to as bloat, twisted stomach, or stomach torsion.

The signs may progress rapidly in acute GDV. The condition is really a spectrum of problems, starting with simple “bloat” or overfilling of the stomach with air or fluid. This may or may not progress to torsion, or twisting of the stomach. GDV usually is an acute situation but, uncommonly, dogs may experience low-grade chronic bloat episodes without experiencing stomach twisting.

Risk Factors

The cause of this dangerous condition is still not fully understood, but some possible risk factors have been identified. It is more common in older dogs and dogs whose relatives have had GDV or had previous spleen removal. Other proposed risk factors include:

Breed/Genetics

Certain breeds are predisposed. In those breeds, there seems to be an association with deep-chested conformation, or barrel-chested conformation. Large or giant dog breeds such as the Rottweiler, German Shepherd, Weimaraner, Saint Bernard, Great Dane, Irish or Gordon setter, Wolfhounds and barrel-chested dogs such as the Boxer, Pekingese, and Dachshund are over-represented. However, any dog breed or “mutt” may develop GDV, and it is very rarely seen in cats.

Food Gorging

Gorging on a single large, daily meal, or gorging on garbage or any other large intake quickly dilates the stomach. Competition at the food dish may increase risk of gorging food. Gas production from food sitting in the stomach will occur which further dilates the stomach and the increased pressure and large stomach volume/weight may produce a twist. Feeding from an elevated bowl and water restriction around meal times are also published risk factors. Movement caused by exercise with an overfull stomach was thought to contribute to risk of torsion, but one study reported no adverse effects. Gulping a large amount of air (aerophagia) may also contribute to bloat. According to one study, in Great Danes small food particle size (< 30 mm) produced increased GDV risk.

Stomach Malfunction

It is thought that poor stomach motility (contractions) is a contributing factor. By not propelling the meal along to the intestines effectively, the stomach stays full or overfull longer, and over time this can lead to stretching of the support ligaments that normally hold the stomach and nearby organs steady. High fat meals also slow stomach emptying.

Stress

Stress, especially fear, may be a risk factor as those dogs characterized as having a hyper or “stressy” temperament are overrepresented.

Signs

Increased pressure and size of stomach, and organ twisting will interfere with blood flow to the stomach and spleen and cause excruciating pain. Loss of circulation to the twisted stomach can lead part of the stomach lining dying off or even bursting (rupture) of the stomach. High pressure in the abdomen will press the diaphragm forward, leading to less room for breathing.

Signs may include heavy panting, anxious attitude, shock, collapse, difficult breathing, drooling, repeated retching, abnormal gum colour, standing or laying stretched out, and a bloated belly. If you tap on the belly behind the ribs, it may make a hollow sound like a drum. Your vet may find elevated heart rate, low blood pressure, heart rhythm disturbances, poor pulses, poor refill time of the gums (the time taken for colour to return to the gums after pressure is applied), and abnormal rate and nature of breaths. The effects of GDV are system-wide; the heart, kidney, or liver may also be seriously affected due to toxins released into the bloodstream from damaged tissues and poor circulation, leading to low oxygen delivery.

Prognosis

If a twisted stomach is not relieved the animal will succumb and die, so this is a true life-threatening emergency. Early recognition, and prompt professional treatment maximizes the chance of success. The animal is at risk for death if it is not admitted to hospital after five to six hours from the time of the onset of symptoms. If you suspect GDV is developing, an immediate assessment by a veterinarian is warranted. The treatment is surgery, with system-wide stabilization. Do not wait until a regular clinic is open if signs occur after regular hours – go to the nearest referral hospital or emergency clinic. If need for surgery is confirmed after the initial examination by a veterinarian, your regular veterinarian may refer you to a 24-hour facility in your area for surgery and aftercare due to the intensive care nature of the condition.

Even with the best treatment, a dog with severe GDV may still die because the circulatory changes lead to a cascade of problems that may not reverse with therapy. About 15 per cent mortality is typical, though death rates increase with more severe cases and those dogs that were not seen until further into the progression of signs. Pancreatitis, systemic inflammatory response syndrome (SIRS) associated with sepsis, organ failure, and heart arrhythmias may follow GDV and surgery and can be as critical as the original GDV. Spleen removal, or partial stomach wall removal will increase the surgical/anaesthetic time of procedure, and risk of complications.

Treatment

Immediate treatment consists of intravenous fluids, oxygen therapy, and decompressing the over-distended stomach by either taking the gas out through a tube put down the esophagus, or in the case where the entrance to the stomach is twisted tightly closed, a trocar (big needle) may be introduced directly into the stomach which is sitting up against the body wall. This will relieve the excess pressure in the stomach and abdomen, which will improve heart and lung function, and helps stabilize the dog until surgery can be performed. Diagnostic testing may include CBC (complete blood count) and biochemistry screening including electrolytes and urine analysis. A radiograph (X-ray) and an ECG (electrocardiogram) will be performed to check the heart function. Blood gases will also be assessed to gauge oxygenation of the system and metabolic shifts in 24-hour facilities.

Surgery under general anaesthetic will be done as soon as the pet is stabilized. The definitive treatment is anchoring the stomach to the body wall (gastropexy) after decompression (removal of fluid and gas), derotation (put back in place) and lavage (rinsing out stomach contents). General abdomen exploration is done to ensure there is no damage to other organs, foreign material, or a tumour that might predispose to GDV. This will prevent future twisting (volvulus), but not simple bloat (dilatation). A full abdomen exploration will be done, and any damaged stomach wall will be removed. The spleen may also be removed if it is damaged.

Anaesthesia poses a definite risk, but without the corrective procedure the animal will certainly die. It is possible death can occur during surgical preparations, during the operation, or after what appears to have been a successful surgery with anaesthetic; even days later due to body-wide effects of the underlying GDV. Post surgery infection is low risk, but if a surgery suture area breaks apart (dehiscence) a second surgery will be required.

Recovery will entail a few days in hospital with continued monitoring and therapy. Rest for at least a few weeks after the dog goes home is essential while tissues heal. Small meal sizes and frequent meal feeding schedules can help to prevent overfilling the stomach.

Preventative/prophylactic gastropexy is being recommended by some surgeons for those dogs of breeds known to be at high risk, for GDV, or for dogs with relatives having had GDV. This is generally done at the time of the neutering operation.