Most owners have to deal with doggy diarrhea at some point. While this common condition often clears up with some at-home diarrhea treatment, dog diarrhea can also be a symptom of something more serious. For example, the sudden development of aggressive, bloody diarrhea can be a symptom of hemorrhagic gastroenteritis (HGE). Also known as acute hemorrhagic diarrhea syndrome (AHDS), this condition can be life-threatening for dogs. Learn more about HGE in dogs and how it’s diagnosed and treated.
Symptoms of HGE in Dogs
This condition’s clinical name recently changed from hemorrhagic gastroenteritis (HGE) to acute hemorrhagic diarrhea syndrome (AHDS). The name hemorrhagic gastroenteritis inaccurately suggests stomach inflammation. “Researchers looking for changes in the intestinal lining of dogs found that a lot of them did not have inflammation in their stomach,” says Dr. Katie Tolbert, clinical associate professor at the Texas A&M Gastrointestinal Laboratory.
This syndrome is common in small breeds or toy breeds, including:
However, one study surveying 237 dogs showed AHDS as most prevalent in Labrador Retrievers, so dogs of any size can contract it. This non-contagious condition can also occur at any age, but it is more common in middle-aged dogs.
What Causes HGE in Dogs?
AHDS is referred to as a syndrome because we still don’t fully understand the cause. However, current research suggests a particular toxin contributes to the development of the disorder in some dogs.
Dr. Tolbert explains that Clostridium perfringens is a bacterium that lives naturally in the gastrointestinal tract. A specific type of Clostridium perfringens makes the problematic netF toxin. Infections related to (or hypersensitivity to) Clostridium perfringens or netF toxin may play a role in causing AHDS.
And there could be other predisposing factors. In one study, AHDS cases appeared more often in winter. Cold weather or snow ingestion, along with a history of chronic intestinal issues, may play a role in contracting AHDS.
What Are the Signs of HGE in Dogs?
If your dog has mild diarrhea at home, you might only need to head to the vet if symptoms persist for several days, if your dog’s condition rapidly deteriorates, or if other concerning signs accompany diarrhea. However, delaying treatment for AHDS can be life-threatening.
The symptoms and severity of AHDS are highly variable. However, typically, dogs have a rapid onset. Dr. Tolbert says dogs can go from healthy to very ill within 12 hours. Vomiting occurs in around 50% of cases, followed by acute watery and bloody diarrhea (which may look like raspberry jam). In severe cases, accelerated fluid loss can lead to extreme dehydration, hypoproteinemia (low protein levels in the blood), hypovolemic shock (a decrease in circulating blood volume, which negatively affects heart function), and acute kidney injury.
Dogs often experience low blood pressure and may be weak and tachycardic (having an increased heart rate). They may also experience abdominal pain. Sepsis (blood poisoning) is a rare but serious development.
Dr. Tolbert says you should always consult a veterinarian if your dog’s diarrhea isn’t stopping, and if it’s accompanied by any of the following:
- Lethargy
- Vomiting
- Lack of appetite
- Dry mucous membranes on the gums
- High rectal temperature that is persistently above 103 degrees Fahrenheit when indoors
She also suggests doing what’s called the “skin tenting test” to check hydration levels. If you pull up the skin on the nape of your dog’s neck and it remains in a tent shape, that could be a sign of problematic dehydration.
How Is AHDS in Dogs Diagnosed?
Unfortunately, rapid or noninvasive tests aren’t currently available for diagnosing AHDS. “There is a test to detect the netF toxin, but it will generally come back after 48 to 72 hours. By the time you get the results, the dog is dead or better,” Dr. Tolbert says.
Instead, diagnosis happens through a process of exclusion. “AHDS diagnosis usually comes after seeing the constellation of clinical signs, history, and lab work findings in a dog,” notes Dr. Jessica Pritchard, clinical assistant professor in small animal Internal medicine at the University of Wisconsin-Madison School of Veterinary Medicine. Dr. Pritchard says that your dog’s vet will need to rule out other diseases, like “severe parasitism, pancreatitis, foreign body obstruction, bleeding disorders, and certain types of cancer.”
Parvovirus is a common cause of acute hemorrhagic diarrhea in dogs, but it typically affects puppies and unvaccinated dogs. Rapid test results are available for this contagious virus.
Your vet will run a PCV (packed cell volume) test to measure red blood cells and determine if your dog is anemic. When the results show a low PCV, this is a sign of true gastrointestinal bleeding rather than AHDS. If the results show a high PCV, the cause is likely dehydration (since the blood is more concentrated).
Your vet will probably also order a complete blood count (CBC) and analyze things like proteins, enzymes, lipids, and hormones via a biochemistry serum to rule out conditions like Addison’s disease.
How Is HGE in Dogs Treated?
Dr. Pritchard explains that supportive care is the main method of treatment. Your veterinarian will usually start your dog on IV fluids right away to rehydrate them rapidly and then reassess to determine what else is required. “Some dogs respond really quickly to fluids,” Dr. Tolbert says. “Other dogs don’t respond to them at all and need more aggressive intervention.”
Less commonly, dogs will need blood products to help them absorb the fluids effectively and aid their recovery. If your dog is continuing to vomit, your veterinarian may administer medication to help with vomiting.
Antibiotics may or may not be a part of AHDS treatment. However, some veterinarians may want to minimize their use, given concerns over growing antibiotic resistance in dogs and humans. Dr. Tolbert explains that one exception may be if dogs start showing signs of developing a bacterial infection in their bloodstream. Other vets may prescribe antibiotics to treat hemorrhagic diarrhea.
Once your dog has recovered sufficiently, your veterinarian will offer them small amounts of easy-to-digest food. Foods like boiled chicken breast and white rice or a GI-specific veterinary therapeutic diet can help support a return to gut health. Your vet may also suggest using GI-supportive probiotics for up to a month after the AHDS has resolved.
Prognosis for HGE in Dogs
Dr. Pritchard explains that most dogs with AHDS make a good recovery with early supportive care. While the syndrome can be life-threatening without intervention, AHDS can be fatal in less than 10% of hospitalized dogs.
Typically, dogs leave the hospital within a few days. Longer stays are possible for more severe cases. It’s rare for dogs to have repeat occurrences of AHDS, but some can develop chronic gastrointestinal issues because of the damage inflicted on their intestines.