Things are usually quiet at my office over the winter holidays. Everyone is focused on family and friends, not fleas and fecal tests, but this year I did get one call on Christmas Day, about a Shiloh shepherd who was vomiting repeatedly. Shiloh shepherds are a relatively new breed developed by crossing German shepherds with Alaskan malamutes. They are generally bigger, heavier, and fluffier than standard German shepherds, and also touted as having gentler temperaments and less risk of hip dysplasia. One thing they do have in common with their relatives: They are large, deep-chested dogs. This particular owner was keenly aware of the risk of a condition called gastric dilatation-volvulus (GDV) in dogs with this conformation.
Let’s take a hypothetical dog named Samaria. It all starts when gas begins to accumulate in Samaria’s stomach. Instead of passing normally into the intestines to create a happy, farting dog, the gas stays in his stomach, which distends like a balloon. This is bloat. Caught at this stage, it may be treated medically. As the process progresses, however, the stomach rotates, twisting into an abnormal position. This is “volvulus” — the scientific term for rotation around a long axis. Picture someone making a balloon animal with Sammy’s gas-filled stomach. This is a surgical emergency.
GDV cuts off blood supply to the stomach, leading to severe tissue damage. It locks the gas inside the distended stomach. This puts pressure on the large blood vessels running through the abdomen, compromising blood flow to the heart. This leads to circulatory shock. The spleen lies alongside the stomach, and may also twist, making a bad situation worse. Signs, which can be surprisingly subtle for such a serious disease, may include distended abdomen, repeated, nonproductive retching, excessive drooling, pale gums, and restlessness. Heart and respiratory rates rise as pain and distress increase. Left untreated, GDV is fatal.
No one knows for sure why some dogs are prone to GDV. We do know that thin, deep-chested large breeds such as Great Danes have increased risk. Studies indicate Great Danes have almost a 40 percent chance of having GDV over the course of their lives. Other commonly affected breeds include St. Bernards, Weimaraners, Gordon setters, Irish wolfhounds, standard poodles, Doberman pinschers, Rottweilers, and German shepherds, but GDV has been diagnosed in all kinds of dogs, even little dachshunds. Numerous risk factors have been theorized: eating too fast or from a raised food bowl, eating only dry food, or only one meal a day, exercising immediately after eating, or even having a fearful or nervous temperament. Middle-aged to older dogs are more commonly affected. As far as gender-related risk, there is no clear consensus, though some say male dogs have a higher incidence. Recent studies support a genetic component in Great Danes. This may eventually be found true of other breeds as well, but the reality is no one has yet untangled the complicated underlying causes of this devastating syndrome.
I advise owners of high-risk breeds to keep over-the-counter Gas-X, a simethicone product, at home to give if their pup seems gassy. Don’t confuse Gas-X with “antacids” like Tums, Rolaids, Prilosec, or Nexium. None of those treat gas. You want simethicone. If you think your dog may be bloated, put your hands on either side along his ribs, higher up toward his spine. Now slide backwards. When you get to the end of his ribs, does he feel puffed up? Tight, like a drum? Call your veterinarian. Right now. Right. Now. Keep in mind not every GDV dog appears bloated to the naked eye. Diagnosis is best made with radiographs. Even that is not always as straightforward as you might think. We look for a specific pattern on X-rays called the “C-sign,” “double bubble,” or “Popeye’s arm,” but even with radiographs, cases thought to be “just” bloat sometimes are actually GDVs, and vice versa.
Once we have a tentative GDV diagnosis, we must quickly stabilize Samaria, treat for shock, and relieve the pressure in the gas-distended stomach. This can be done either by sedating and passing a stomach tube, or by trocarization, which essentially means popping a hypodermic needle through the body wall into the distended stomach. This creates a tiny vent hole for the gas. Once stabilized, immediate surgery is necessary to correct the position of the stomach. If we are lucky, the entire stomach returns to a healthy pink after repositioning. Because of the high risk of recurrence, a simultaneous procedure called gastropexy is recommended, to tack the stomach in place. (One preventive step owners of high-risk breeds can take is to have a prophylactic gastropexy performed at the time of neutering.)
If we are not lucky, the surgeon may discover that lack of blood supply to the twisted gut has resulted in irreversible damage. This requires surgical removal of all nonviable tissue, or Samaria will die even if the twist is corrected. Many owners opt for euthanasia at this point, as these dogs have much worse prognoses. Many dogs survive the initial surgery only to die in the days following, so optimum postoperative care is extremely important. Treatment includes intravenous fluids, antibiotics, and pain and anti-vomiting medications. Monitoring includes blood pressure, clotting ability, and repeated ECGs, as the risk of deadly cardiac complications lasts as long as three days.
When I was a young vet, the vast majority of GDVs died, even in the hands of specialists. Today that statistic has improved dramatically, with survival rates as high as 60 to 85 percent, but we Vineyarders are still faced with the limitations of Island life. While Samaria’s best hope is to get to a specialty clinic with board-certified surgeons and 24-hour intensive care, time is also of the essence. My Christmas Shiloh shepherd did not have a gastric dilatation-volvulus. She wasn’t even bloated, though she did have other serious problems. I was glad her owner chose to bring her to see me. When it comes to GDV, when in doubt, don’t delay. Call your veterinarian. Right now.
