Bloat: Gastric Dilatation and Volvulus in Dogs

What is gastric dilatation and volvulus (GDV)?

Gastric dilatation and volvulus (GDV) is a life-threatening disorder most commonly seen in large, deep-chested dogs, although any dog may be affected. In its early stage, the stomach fills with gas, causing a simple gastric dilatation or “bloat”. Sometimes, the condition progresses no further than a bloat.

A GDV occurs when the bloat progresses into a volvulus, in which the huge, gas-filled stomach twists upon itself so that both the entrance and exit of the stomach become blocked. This is a life-threatening emergency that requires urgent surgery to correct.

What causes the condition?

The exact cause of GDV is unknown. The condition is seen more commonly in large, deep-chested male dogs. Exercise after eating a large meal or drinking large amounts of water may increase risk. 

Anxiety may be a contributing factor to GDV. In recent studies, dogs that were relaxed and calm were at lower risk of developing GDV than dogs described as “hyper” or “fearful”. Numerous other predisposing factors have been investigated, but results have been inconsistent. Some studies have identified a possible genetic predilection to developing GDV. Illness that decreases intestinal motion can also lead to stomach dilation and, subsequently, volvulus.

Is GDV serious?

Yes, this is one of the most serious, non-traumatic conditions seen in dogs. Immediate veterinary attention (within minutes to a few hours) is required to save the dog’s life.

Are some dogs more prone than others?

Yes, statistically, we know that large, deep-chested breeds are more prone to GDV. Predisposed breeds include: Great Dane, Saint Bernard, weimaraner, Irish setter, Gordon setter, standard poodle, basset hound, Doberman pinscher, and Old English sheepdog. However, any dog can bloat, even dachshunds and chihuahuas. The condition has been reported to most commonly occur shortly after eating a large meal, although bloat and GDV can occur at any time.

Dogs weighing over 100 pounds have approximately a 20% risk of bloat during their lifetime. Gastric dilatation (bloat), usually without volvulus (twist), occasionally occurs in elderly, small dogs.

What factors increase the risk of GDV in dogs?

• Feeding only one meal a day
• Having a family history of bloat (e.g., a parent or sibling that has suffered from this condition)
• Rapid eating
• Being thin or underweight
• Having a fearful, anxious, or nervous temperament
• Having a history of aggression towards people or other animals
• Being middle-aged to older (the highest risk group)

What are the signs of GDV?

• A dog affected by bloat may show the following signs:
• Appear distressed or restless
• Salivate profusely
• Have trouble breathing
• Retch without producing anything
• Collapse or be unable to stand

Their stomach (abdomen) may also appear swollen or bloated; this is most obvious on the left side. Gentle tapping of the swelling just behind the last rib often produces hollow, drum-like sounds.

The enlarged stomach presses on the diaphragm and breathing becomes labored. The swollen stomach also presses on the larger blood vessels in the abdomen, compromising circulation and resulting in systemic shock. Ultimately, the dog collapses and the distended abdomen becomes readily apparent as the dog lies on its side.

Can gastric dilatation (GD) and gastric dilatation and volvulus (GDV) be distinguished on appearance alone?

No, GD and GDV often look identical on physical examination. X-rays and other diagnostic tests are necessary to determine if the stomach has twisted.

Why does the dog collapse?

The gas-filled stomach presses on the large veins in the abdomen, which carry blood back to the heart. This pressure compromises blood circulation throughout the body.

Vital tissues are deprived of blood and oxygen, resulting in systemic shock. In addition, the pressure of the gas on the stomach wall results in inadequate circulation to the wall, causing tissue death within the stomach. 

Digestion ceases and toxins begin to accumulate in the blood, worsening the shock. As the stomach continues to swell, the stomach wall can rupture.

What can be done to treat bloat or GDV?

GDV is an immediate and life-threatening emergency and requires immediate veterinary intervention. It is imperative to reduce the pressure on the stomach wall and internal organs as soon as possible. Your veterinarian may first attempt to pass a stomach tube. If this is not possible, due to twisting of the stomach, a large bore needle or catheter may be inserted through the skin and into the stomach to relieve the pressure in the stomach.

"Once the patient becomes stable, the GDV must be surgically corrected."

Shock must be treated immediately, using intravenous fluids and emergency medications. Once the patient becomes stable, the GDV must be surgically corrected. It may be necessary to delay this major abdominal surgery until the patient is able to undergo anesthesia.

How is the surgery done?

The primary goals of surgery are to return the stomach to its normal position, to remove any dead or dying stomach tissue, and to help prevent future GDV. Several different techniques may be used, but the most common is gastropexy (suturing the stomach wall to the abdominal wall). Your veterinarian will determine the most appropriate technique or combination of techniques for your pet’s condition. Sometimes the spleen will need to be removed if it has been significantly damaged by the twisted and bloated stomach.

What is the survival rate for GDV?

Survival depends on many factors, including how long the pet has had GDV, the degree of shock, the severity of the condition, cardiac problems, stomach wall necrosis, and length of surgery.

Even in relatively uncomplicated cases, there is a mortality rate of 10%-45% for GDV. Factors that affect the outcome include heart arrhythmias that were present at the time of diagnosis, the need to remove part of the stomach, the need to remove the spleen, and elevated blood levels of lactate.

Can GDV be prevented?

Gastropexy (surgical attachment of the stomach to the body wall) is the most effective means of prevention. In high-risk breeds, some veterinarians recommend performing prophylactic (preventative) gastropexy at the time the dog is spayed or neutered. See handout “Gastropexy” for more information on this surgery. Gastropexy does not prevent dilatation (bloat) but does prevent twisting (volvulus) in most cases. Without gastropexy, the recurrence rate of bloat has been reported to be as high as 75%.

Careful attention to diet, feeding and exercise regimens may also help prevent gastric dilatation. Dogs with a first-degree relative that developed GDV should not be used for breeding. Do not hesitate to discuss any concerns about this serious condition with your veterinarian.