Hemorraghic Gastroenteritis (HGE)

By Jenny Drastura

HGE is a life-threatening disease that can occur in small and medium-sized breeds, and has an excellent cure rate. Seeing our dogs with bloody diarrhea can give us a real scare. It can be a sign of a small nuisance like a minor gastrointestinal upset or the dog swallowing bits of a hard toy. It can also signal a more serious illness. One of these illnesses is hemorraghic gastroenteritis. This type of diarrhea must be distinguished from other types as soon as possible as the disease can be fatal within 24 to 48 hours. Before you become too alarmed, the treatment success rate is excellent if the disease is caught early and treated aggressively.

HGE vs. Parvovirus
Parvovirus is usually the first disease that comes to mind when your dog has an acute onset of bloody diarrhea. These patients also usually show severe vomiting and dehydration. Parvo is most commonly seen in dogs 3 to 6 months of age. The diagnosis is confirmed by identifying the presence of the virus in the feces in the early stages. The in-office ELISA test is also used. In later stages, there is a change in the white blood count. Parvo is transmitted by exposure to the feces of an infected dog. Vaccination protocols have been established and are generally effective in preventing the disease. Vaccine failures, of course, can occur.

HGE is not contagious. It primarily affects younger dogs, but may be seen in all ages. Toy and medium-sized dogs appear to be at increased risk. The disease is characterized by a sudden onset of vomiting, dehydration and profuse bloody diarrhea. As the condition progresses, the dog will eventually go into a state of circulatory collapse ­ that is, the veins will collapse due to dehydration and loss of fluid from the intestinal tract. If the disease is untreated, death will come from dehydration, hypothermia and shock.

Besides contagion, there are three things that distinguish HGE from parvo. First, the dog often does not appear to be particularly sick in the early stages of the disease, while the parvo dog will be obviously ill. Secondly, there is a large increase in red blood cells due to the decrease in fluid content of the blood as dehydration progresses. In laboratory terms, the dogıs pack cell volume (PCV) will be high. A PCV of more than 55 is an indication that the blood has thickened. Greater than 70 is a sign of serious illness. The white blood count (WBC) can be high, low or normal. Thirdly, in HGE the diarrhea appears more clotted due to the high presence of red blood cells. It is described in veterinary books as being malodorous and looking ³similar to strawberry jam.² (Sorry readers.)

Treatment
Once HGE is diagnosed, aggressive supportive therapy with normal saline or lactated Ringerıs solution is started intravenously to treat the circulatory shock. An antibiotic is prescribed as well. Food is withheld for 12 to 24 hours, allowing the intestines to rest. Bland food such as chicken and rice or a commercial diet is introduced in small amounts. There is a gradual change to the regular diet unless that diet is thought to be a factor in the HGE. Other tests may be given during the course of treatment to monitor electrolytes, renal function, etc.

The exact cause of HGE is not known. It most closely resembles acute hemorraghic enteritis in humans, a disease caused by a strain of the E. coli. Or it may be caused by a toxin produced by the bacteria Clostridium perfringens. Another theory is that it is the bodyıs anaphylactic reaction to undetermined toxins. Fortunately, even in the most seemingly hopeless cases, rapid recovery can occur with the proper treatment. Residual effects are rare. There is sometimes a recurrence in HGE, although subsequent cases are not necessarily more serious. As long as you are informed about this insidious disease, your dog will do fine if it develops.

Note:
My interest in HGE stems from the fact that two of my dogs have had this disease. The dogs are not closely related, and there were 10 years between the cases. To show you how the symptoms can vary, the first dog vomited undigested food twice in a period of three hours and otherwise seemed fine and bouncy. A few hours later there was a small amount of the clotted diarrhea stuck to her hair, and she was still acting fine. She slowly began to weaken on the way to the vetıs office. Her PCV was 60. The second dog had a huge amount of diarrhea first and one episode of vomiting. She was quiet but not necessarily weak. There were several very bad cases of bloody diarrhea while she was in the hospital. Her recovery was a little slower than the first dogıs, though her PCV was lower. Both were hospitalized for two nights and recovered very nicely. They are small dogs but were slightly older than the usual profile of HGE were 6 years old at the time.

Sources
Golden, Dennis L., DVM ³Acute Diarrhea in the Dog.²  Pedigree Breeder Forum Magazine, 1994.
Tams, Todd R., DVM.  Handbook of Small Animal Gastroenterology.
Philadelphia: W.B. Saunders Company, 1996.

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