Hemorrhagic Gastroenteritis (HGE)
One of the more common problems I see on an emergency basis is a disease process called Hemorrhagic Gastroenteritis, also known as “HGE.” The most common history I hear from owners is their dog started having diarrhea and then all of a sudden it became very watery and bloody. This can appear horrifying to first time observers and usually prompts an immediate trip to the ER.
Hemorrhagic gastroenteritis is a potentially life-threatening intestinal condition of dogs that manifests as a sudden onset of bloody, watery diarrhea with vomiting often being part of the syndrome. Sloughing of the lining of the intestines occurs from severe inflammation leading to “chunks” of tissue in the otherwise watery stool; we describe this as “raspberry jam” diarrhea. This process is extremely dehydrating- much more than you would think from the amount of diarrhea observed. If it is not promptly treated, the dog can go into shock from this massive loss of fluid volume.
Smaller dog breeds seem to have a predisposition towards HGE, and it should be noted that the smaller the dog, the more dangerous this condition is. Small dogs are like little babies in human terms, and they just don’t have the same bodily reserve that a 60-pound dog would have… it doesn’t take much for a small dog to become severely dehydrated.
What causes HGE?
Stress, sudden dietary changes, and hyperactivity seem to be predisposing factors but the actual cause remains unknown. In short, the condition is truly another bizarre medical mystery, and I can relate to owner’s confusion and frustration when they ask, “Yeah, but what caused it?” I would have to say from my personal perspective and experience that over 80% of HGE cases I treat do not have an exact cause that you can point your finger at.
How is this condition diagnosed?
There are no specific tests for HGE but a test called a packed cell volume (also called PCV or hematocrit) is helpful in narrowing down the diagnosis. This is a test that can be performed using a few drops of blood. The percentage of the blood volume made up by the red blood cells is measured. A normal PCV for a healthy dog is 37-55%, meaning that 37-55% of the blood volume should be red blood cells (the rest of the volume is fluid and white blood cells). When the patient becomes very dehydrated, there is less fluid in the blood stream and the percentage of blood fluid drops, and consequently the percentage of red blood cells rises. A dog with HGE will generally have a PCV greater than 60%.
The measurement of the PCV also includes a measurement of total protein (sometimes called total solids). In HGE, the total protein measurement from the blood sample is low or normal.
The very high PCV, the low total protein, and acute onset bloody watery diarrhea in a dog generally points to a diagnosis of HGE.
One of the things that make “diarrhea difficult,” is that no matter what the underlying cause is, the clinical picture looks exactly the same. Because of this, we may still recommend that additional tests such as radiographs, a fecal exam and blood work be performed to make sure that there is not a more serious problem causing the clinical signs.
HGE really becomes a diagnosis of exclusion… when blood work, radiographs and fecal exams are normal, we highly suspect HGE as the cause.
What is the treatment for HGE?
The heart of therapy is aggressive fluid replacement. The goal is to get the PCV back to the normal range and keep (or get) the patient out of shock. Food is withheld for at least 12-24 hours and then gradually introduced after the vomiting has resolved. Symptomatic treatment for nausea and belly discomfort is typically included, as is antibiotic therapy. One to three days of hospitalization is commonly required for treatment.
With early and aggressive treatment, life-threatening complications are generally avoided and dogs return happily home. There are no long-lasting effects of HGE, however, some dogs that have “sensitive GI tracts” to begin with can have the syndrome recur in the future.
Questions? Topics you’re dying to learn about but were afraid to ask? Let me know! See you next week for another installment of PETS University!