We don’t know what causes HGE. Theories vary between a bacterial infection of the gastrointestinal tract (Clostridium perfringens has been blamed) to adverse reactions to food or parasites. For some reason, young, small breed dogs are at highest risk, as are individuals who can be described as high-strung or stressed.
We do know what happens during a case of HGE, however. Even though it is not inflamed, the lining of the intestinal tract becomes very leaky. Fluid, protein, and red blood cells seep out of vessels within the intestinal wall. The body responds with a process known as splenic contraction. The spleen serves as a reservoir for red blood cells. When the body senses that more may be quickly needed, the spleen releases its reserves into circulation.
Counterintuitively, despite large amounts of water being lost into the intestinal tract, dogs with HGE often do not appear to be clinically dehydrated. This finding is a red herring, however. Hypovolemic shock can quickly develop.
The combination of splenic contraction and a leaky bowel produce the laboratory values that are typically seen with HGE:
- Elevated red blood cell counts; a dog’s packed cell volume is often 60% or more (37-55% is considered normal)
- Normal or low blood protein levels
Combine these findings with a history of acute onset of “raspberry jam” diarrhea in an otherwise healthy dog, and HGE is the most likely diagnosis. Diagnostic testing to rule out other potential causes (parvovirus, rodenticide poisoning, Addison’s disease, intestinal parasites, etc.) is sometimes necessary.
Treatment for HGE is essentially supportive but needs to be aggressive and started ASAP. Intravenous fluid therapy is vital for preventing shock and saving lives. Most patients receive antibiotics just in case a bacterial infection is to blame. Some dogs also vomit with HGE, and anti-nausea medications will be prescribed in these cases.
Once a dog’s condition is improving and vomiting is no longer an issue, water and small, bland meals can be offered, fluid therapy tapered, and oral medications dispensed. Most dogs need to stay in the hospital for a couple of days until they are stable enough to go home and finish their recovery. HGE is not contagious, but about 10 percent of dogs have more than one episode during their lives.
Treated early and aggressively, hemorrhagic gastroenteritis has a good prognosis.
Dr. Jennifer Coates