Endotoxaemia?

[Piaffe63]

I was looking through one of my horsey magazines, and it was talking about changing diet too quickly. Then it said so and so could result in poor performance, colic, laminitis and endotoxaemia. But it didn't say anything else, and I know about the other three, except endotoxaemia, which I've never heard of before. But there was no explanation, so is this something common that I should know about? I looked in my big veterianary manual, but couldn't find anything! Thank you in advance!

 

[alsiola]

There have been entire PhD theses written on endotoxaemia, so it is a big subject but here are the basics.
Most simply, endotoxins are components of bacterial cell walls (also known as LPS - lipopolysaccharides). Endotoxinaemia means that these cell wall components have made their way into the bloodstream.
It is normal for a horse to have these endotoxins in their gut - usually the gut wall is a protective barrier that stops them entering the bloodstream. However, if diet changes rapidly then various changes occur in the colon, in terms of bacterial population and acidity. This can lead to a loss of integrity of the gut wall, and endotoxin entering the bloodstream.

Once in the bloods, there are many effects. Most importantly they will cause:
1) Blood vessel dilation and leakiness, leading to loss of fluid and hypovolaemia (like dehydration)
2) Activation of the clotting cascade, with clotting occuring within blood vessels, and all the clotting factors being used up. This is called DIC (Disseminated Intravascular Coagulopathy). Or due to its terrible prognosis, DIC=Death Is Coming although this is less official!
3) Inflammation of the blood vessels and surrounding tissues.

The prognosis is poor, and the horse will often die due to inadequate blood volume and lack of ability to clot blood.

It is most commonly found after colic surgery, or during severe colitis (as in the situation you described), but could theoretically happen with any gram-positive bacterial infection.

 

[Piaffe63]

Thank you, that was very useful!