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Mystery Illness Comes on Like Wildfire and Can Be Deadly — What to Know Now

Its cause is a mystery. Theories abound, but not a lot of definitive information. One thing's for sure - it comes on like gangbusters and can be fatal without equally swift and aggressive action. Find out the likely breeds, ages and fast-onset symptoms, so you'll be prepared.

hemorrhagic gastroenteritis

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  • Hemorrhagic gastroenteritis (HGE), is a potentially life-threatening condition seen primarily in 2- to 4-year-old toy and small breed dogs
  • The cause of this mysterious condition is unknown; primary symptoms include the sudden onset of bloody diarrhea and vomiting that ultimately also turns bloody
  • Diagnosis is made based on symptoms, specific bloodwork measures and a diarrhea panel
  • Treatment for HGE is primarily supportive and must be started immediately and aggressively to achieve the best outcome
  • A percentage of dogs who have one episode of HGE will have a recurrence, so it’s especially important for guardians of those dogs to know the signs and seek immediate veterinary care

Editor's Note: This article is a reprint. It was originally published August 27, 2017.

Hemorrhagic gastroenteritis, or HGE, is a very serious condition that can affect males and female pets of all breeds and ages, however, it’s most often seen in 2- to 4-year-old toy and small breed dogs, especially miniature Poodles, miniature Schnauzers, Dachshunds, Yorkshire Terriers, the Pekingese, the Cavalier King Charles Spaniel, the Shetland Sheepdog … and standard Poodles.

Interestingly, dogs described as high-strung, hyperactive or stressed seem to have a higher incidence of HGE as well. HGE isn’t thought to be contagious from dog to dog, however, dogs living together have been reported to develop the condition at the same time, which is suspicious. Also, there have been outbreaks reported in some areas of the country, which is also suspicious.

Causes of Hemorrhagic Gastroenteritis

In dogs with HGE, the lining of the intestinal tract becomes suddenly very leaky, even though no inflammation is present. The leakiness allows fluids, proteins and red blood cells to seep out of vessels within the intestinal wall and into the lumen or opening of the intestine. The dog’s body responds with what we call splenic contractions. The spleen serves as sort of a blood bank. It’s a holding tank for red blood cells, and when the body senses blood loss and the need for more red cells, the spleen releases its reserve into circulation.

The cause of HGE is a mystery. Theories include indiscriminate eating and immune-mediated disease. The two cases of HGE I saw last year developed after vaccines were given. Other potential causes include toxin exposure, pancreatitis, stress, anxiety, hyperactivity, an allergic reaction to food or an inhalant, internal parasites and bacterial infection in the gastrointestinal (GI) tract.

A small study of 10 dogs with HGE found mucosal lesions in the intestines, but not the stomachs of the dogs, and all 10 had clostridium bacteria in the small intestine.1 The study authors recommended renaming the condition “acute hemorrhagic diarrhea syndrome,” because they found no evidence of gastritis or inflammation of the stomach itself.

It has been assumed the stomach is involved in HGE because vomiting is almost always present, however, that wasn’t the case with this study. In addition, the small and large intestines showed necrosis rather than inflammation.

To confuse things further, in some areas of the country the condition seems to occur seasonally in the spring and fall, and that was my experience last year — two cases in the spring. There have also been regional outbreaks. However, all testing related to those cases has turned up nothing useful in nailing down a root cause.

HGE Symptoms and Diagnosis

Most cases of HGE are acute, meaning they come on suddenly without warning in otherwise healthy dogs. The primary symptom of hemorrhagic gastroenteritis is either dark or bright red bloody diarrhea that resembles raspberry jam, along with sudden and profound vomiting that starts out as mucus or bile, but eventually becomes bloody. Some dogs may also have decreased appetite, a painful abdomen, lethargy and a fever.

HGE can be fatal, so immediate veterinary care is essential. Strangely, dogs are usually not yet dehydrated when first examined, however, it can develop quickly and result in a drop in blood pressure, elevated red cell count, problems with blood clotting, shock and kidney failure.

A diagnosis of HGE is typically based on a dog’s symptoms (sudden onset of vomiting and bloody diarrhea), along with an elevated packed-cell volume (PCV) of greater than 60% in most cases, which is seen in the red blood cell count, and normal or low blood protein levels. A positive culture for C. perfringens can also be helpful for diagnostic purposes.

Your veterinarian may want to run a full diarrhea panel, which would be my suggestion. X-rays aren’t useful in diagnosing HGE, but can be helpful in diagnosing other potential conditions that cause GI symptoms. Diagnostic tests to rule out other issues, such as parvo, ingestion of rat poison, intestinal parasites, Addison’s disease and others are sometimes necessary. Diagnosis is often a process of eliminating other causes of bloody stools and gastrointestinal distress.

Treatment Options

Treatment for HGE is primarily supportive, but it must be started immediately and aggressively to give your dog the very best chance for survival. Intravenous (IV) fluids will be given to prevent shock. Antimicrobials are often given to combat an acute bacterial infection, and for dogs with vomiting, anti-nausea medications may be administered. On rare occasions, blood transfusions may be required if the dog has lost a tremendous amount of blood.

Many holistic veterinarians (including me) also use a Chinese herbal remedy called Yunnan Baiyao. In the middle of the Yunnan Baiyao packet, there’s a little red emergency pill that we use regularly for this condition. Many veterinarians also use high potency homeopathic remedies to rapidly help stop the bleeding. I recommend both.

Once a dog’s condition improves and he’s no longer vomiting, water by mouth and small bland meals can be instituted. IV fluids will be tapered off over time to make sure he can maintain his hydration, and oral meds are discontinued. In most cases, HGE runs its course in a few days in dogs given immediate treatment and appropriate supportive care. 

About 10% of dogs who have one episode of HGE tend to have more in the future. While preventing HGE is difficult because we still don’t know what causes it, it’s important to ensure that your dog’s immune system remains strong and resilient. Hemorrhagic gastroenteritis is potentially life-threatening because it progresses so rapidly, so again, if you recognize symptoms in your pet that could be HGE, it’s important to act on your hunch and get your pet to your veterinarian immediately.

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