HGE: OMG!
Help my dog's poo looks like strawberry jam!
There are lots of reasons why your dog's poo might be bloody: eating stuff that irritates the gut; bacterial, viral and protozoal infections; and medication side effects, to name a few. In many cases, it resolves on its own with some bland food and time.
But there's also a particular type of acute bloody diarrhoea that we don't have a cause for. This is called haemorrhagic gastroenteritis (HGE) or, more recently, acute haemorrhagic diarrhoea syndrome (AHDS). While AHDS is a more accurate term because the stomach (gastro) isn't really involved, more people are familiar with HGE.
What is HGE?
HGE is characterised by a well dog becoming suddenly sick with bloody vomiting and/or diarrhoea.
Another key characteristic is a high packed cell volume (PCV). A PCV is a blood test that tells us about the ratio of red cells and water (plasma) in the blood. With HGE, the high PCV reflects a loss of water from the blood. This makes the blood thicker and with very high PCVs, the blood can struggle to flow through the smallest vessels (capillaries).
Even though you see your dog losing blood, he's actually losing a lot more water out of his system. This can lead to what's called hypovolaemic shock, where there is not enough 'volume' in the vascular system to carry around oxygen and take away waste.
There is often a spike in HGE cases in spring.
Who gets HGE?
HGE is most common in young to middle-aged small breed dogs.
A possible reason for this is that the lower a dog's body weight (due to breed/size not skinniness) and the younger he is, the more likely he will be affected by stress-related excitability and hyperactivity. Stress is known to affect gut motility and bacterial balance (the biome). Our 'stressy' and excitable dogs tend to have more gastrointestinal symptoms in general than our more chilled out ones.
What happens during HGE?
It seems that HGE is due to a sudden:
- death of intestinal lining cells
- infiltration of neutrophils (a type of white blood cell) into the intestinal wall
The suspected trigger for this is a toxin released by bacteria within the gut (Clostridium perfringens). The toxin ulcerates the lining of the intestines and the intestinal blood vessels. These make the intestine more permeable or 'porous', allowing leakage of blood and water into the gut.
Why the bacteria overgrow and/or release the toxin is not yet clear. Apart from stress, there are likely to be many factors involved.
What are the signs of HGE?
The main sign is sudden-onset bloody diarrhoea. The diarrhoea is often described as strawberry jam due to its colour and texture, but it may also be watery. Although the amount of diarrhoea passed may be quite low, a rapid dehydration can occur.
Vomiting (with or without blood) is often part of the syndrome. About 80% of dogs vomit about 10 hours before the bloody diarrhoea starts.
As opposed to a lot of other vomiting and diarrhoea diseases, dogs with HGE tend to become very lethargic very quickly.
How is HGE diagnosed?
There is no specific test for HGE. The PCV can be very helpful for making a diagnosis. A normal PCV is 37–55% (that is 37–55% of the blood is made of red cells and the rest is fluid). Dogs with HGE tend to have a PCV of around 57%, with some having much higher results. A PCV of >70% can mean that blood is 'too thick to flow' through small vessels.
When we perform a PCV we also check the total protein (TP) level of the blood. In HGE, the TP level is relatively low.
How is HGE treated?
The mainstay of treatment for HGE is aggressive fluid replacement. Essentially, we're talking treatment for shock – we need to rapidly put fluid back into the vasculature and return the PCV to normal. This means that patients with HGE need to be admitted to hospital for IV fluids.
We also give antinausea medication as needed. Antibiotics are often, but not always, given.
Most patients make a rapid and excellent recovery. Many can be discharged from hospital within 24 hours (most are out within 3 days).
Take out points
- Bloody diarrhoea is common and in most cases it settles by itself
- Bloody diarrhoea that is accompanied by vomiting (with or without blood) and lethargy may mean HGE
- HGE can rapidly lead to shock and even death
- HGE needs veterinary treatment (IV fluids in hospital)
- If you are concerned about any symptoms, call us!