Refergency Friday and the Horse With Haemorrhagic Colitis

Warning: Blood is involved.

I once heard an internal medicine resident call Fridays "Refergency Friday," because it always seems that everyone waits until then to send over all the critical, complicated, or difficult cases. Today supported this trend, when the only emergency in all of equine roster rocked up at 9am. Not only was it an emergency, it was a potentially infectious (and potentially zoonotic) disease and the horse had to go straight into isolation.

Isolation is this little barn separated from the main equine barn. To go in, you have to put on special overalls and special boots, walk through disinfectants, and it's not a bad idea to put on two pairs of gloves. There are certain criteria for whether or not to put a horse in isolation:

2/3 of the following:
1. Fever
2. Diarrhoea
3. Low white blood cells

In our particular instance, we didn't find out that the horse had those things until it actually showed up. This was a prelude to the recurring theme of the fact that the history changed pretty much every single time someone talked to the client. However, the more immediate problem is that there are no supplies in isolation already; you have to bring everything down ahead of time, once you get the call. This makes sense because if the whole point is preventing spread of disease, you don't want to be using anything left over from the last patient that was in isolation.

So this nearly dead horse shows up and goes into isolation, and everyone starts moving at a frenetic pace. Unfortunately, about half the time when someone would ask me for something, I'd look around for it and find nothing. They wanted to put in an IV catheter, but the horse had terrible blood pressure, making it super difficult. Add this to the fact that I didn't have any of the things they actually needed and other students had to keep running back to the main barn to get them, tension got pretty high. Also, since we're students and not only didn't know our way around isolation (since we'd never been there before), the other student and I are totally not horse people and don't even know the basics. If someone asked for a certain object, we wouldn't know what it looked like, or which of several options they wanted. To top everything off, the horse was quite anxious, and it became dangerous on top of difficult to get anything done.

After a tense half an hour to an hour, the horse was finally sedated, catheterised, fluids were running, and things were more under control. Blood and abdominal fluid were sent off to the lab, and there was some time to catch our breath. After some teaching/learning about the physical exam findings and differential diagnoses, I got the lovely job of standing at the rear end with a pottle, waiting to catch what came out so someone could run diagnostics. This poor horse was literally crapping blood. Pure blood.

Things were looking pretty grim. Lab results kept making the picture worse and worse. The horse most likely had dead colon, allowing bacteria to translocate into the bloodstream and cause septicaemia, as well as fluid to collect in the abdomen. Blood was just pouring out the back end. Bloodwork showed that the kidney was showing signs of dysfunction, too. And though it was never confirmed, it was pretty likely that the horse was in disseminated intravascular coagulation (DIC).

They gave the horse some blood plasma, since when you're in a state like that, fluids aren't going to be enough. However, he had some sort of reaction (maybe anaphylaxis, or maybe he was just circling the drain and it was his time), and started getting wobbly, anxious, and then thrashing around. I wasn't there when this happened, but he came this close to killing someone. It was a downhill spiral from there, and he was euthanised.

He was sent over to post-mortem immediately, and we went down to have a look. His entire small and large colon was dead, dark and necrotic and haemorrhagic. The gut contents were mostly blood. It must have been a horrible, painful way to die. From the history, we suspected untreated intestinal parasites as a cause, though some other options include Salmonella, Clostridia, idiopathic colitis, or drug-induced. It's amazing to think that those things could cause such a horrific colitis.