Tuesdays with Tony

Being a Clinic Cat will make you a bit paranoid. I spend a lot of time seeing not-normal horses, and only a small slice of my day seeing normal horses. The hardest not-normal horses we see are the ones my Docs call neurologic. My understanding of the word neurologic is that the connection from the brain to the body parts isn’t working correctly. This can come in many forms, from none of the legs working, to tripping when walking downhill. Let’s talk about how my Docs figure out if your horse is neurologic vs. lame, and what they do about it!

The Nervous System Superhighway

Let’s start with how the system works. (If you’re a neurologist, yes, I know I simplified things a bit. I’m a cat [superior being] explaining things to humans [inferior beings]) Okay: your horse looks at a flake of hay on the ground and thinks, “I’d like to eat that.” The brain sends a signal down the spinal cord to the limbs to say “Move forward towards the delicious food.” There’s another signal that says, “Put your head down so you can reach the food,” and yet another group that instructs the mouth on how best to move the food from the outside to the inside. 

All of this happens via nerves coming out of the brain and talking to other nerves in the spinal cord who send the signal on to the proper part of the body. Honestly, it’s a miracle any of this works on any of us. You can see how there’s ample opportunity for this entire system to go wrong at so many different places. It can go wrong at the brain, at the nerve going to the spinal cord, in the spinal cord, in the one that goes from the spinal cord to the body part, and all the places where there’s a connection between all those things. Like I said, it’s amazing it works at all. 

The Brain

This is going to be a short section. When the brain is the problem, you know. In rare cases like brain tumors, it may start subtle, but within a very short time (think days, not weeks) it’s obvious there’s something very not right with the brain. The more common way my Docs see the brain as the problem are with viruses like Eastern Encephalitis and West Nile virus. These horses have no idea where they are or what they’re doing. It’s awful. Vaccinate your horses for these diseases. Anyway, you know when the brain is the problem. It’s bad. End of section.

The Rest of the System

This is where things get harder. One of the hardest questions my Docs have to answer is, “Is it lame or is it neurologic?” When you have a critter who can’t answer questions, this can be very difficult to determine. If you went to the doctor, they would ask you questions about walking up and down stairs, can you feel it when I poke here, close your eyes and do this task, etc. All of these things help determine if you as a human have a neurologic component to your problem. They can also then do things like x-ray or MRI of your spine, but more on that later. 

My Docs have to come up with all sorts of different tests to ask horses those same questions. A few examples are walking over poles, walking up and down hills, walking with the head up or down, and turning fast. These all set up conditions where the signal has to smoothly and quickly travel from the brain to the body part. Based on responses to these tests, my Docs then work to determine if this a nerve (roadway) problem, or maybe a connection (stoplight) problem, or is it a problem at the destination (the parking lot). Usually it’s the roadway, so my Docs generally start there. 

The Roadway and its Issues

The spinal cord in a horse is pretty dang long. It goes from the ears to the tail. That’s a lot of real estate to have problems with. The most common issue my Docs see is arthritis of the joints that make up the bones of the spinal column. The problem is the nerves have to come from the spinal cord out into the body to carry the signal. This means they have to travel through the bones at strategic points. Those strategic points can get cut off by arthritis causing bony growth to close the hole. In the early stages, this can be tripping, having trouble doing movements like lateral work or transitions, and can even show up as a lameness. There may be good days and bad days, making it difficult on you humans to determine if it’s even real. It can also make it tough for my Docs to see since it may not be happening on the day they’re looking at your horse. Being patient and allowing repeat evaluations is key to figuring out these horses. 

If my Docs are suspicious of a neurological issue based on talking with you and evaluating your horse, they will likely suggest x-rays and ultrasound of the neck, and maybe moving on down the back. This will largely depend on how your horse is showing neurological symptoms. Here’s where things get tricky. Horses are really big. If you want to know what my back looks like, you can plop this entire cat in an MRI or CT scanner and have a very thorough picture of what it all looks like. You will also have a sleepy cat, because you’re going to have to give me some drugs to get that done. No such luck with horses. 

CT can now be done on most of the neck, MRI can be done on the head and some of the neck, but get down low and on into the back and it’s a no-go zone. First off, horses have to be able to fit inside the CT or MRI scanner. It’s basically a donut they have to go through. You need a really, really big donut hole to get an entire horse through, especially when you factor in those long skinny legs. Once you make the donut hole big enough, you can’t beam the signal all the way across the hole, so you can’t make an image of everything. Physics is the problem, and there’s very little you humans can do to overcome the Laws of Physics. This means there may be lots of combining x-rays and ultrasound to attempt to determine what the 3D structure of the back looks like. There’s also likely to be lots of testing of movement and head scratching on the way to a diagnosis. As you’re realizing, it’s not an easy or straightforward process.

Treatment

I’m being a less-than-upbeat cat today, but treatment for many of these things can be difficult. Arthritis can be managed with stretches, strengthening exercises, and targeted injections. However, it’s an advancing problem and eventually it will get ahead of what my Docs can manage. Knowing what’s normal for your horse can be key to identifying problems early! 

For many of the other neurological issues seen with horses, it can be tricky to come up with good treatment options. Working closely with my Docs to figure out the exact problem will help narrow down potential treatments. 

Neurological disease is tough. It’s tough to identify, and tough to treat. If your horse is doing something weird, be sure to check in with my Docs sooner rather than later. Finding the cause of the weirdness early goes a long way to better treatment options. If you want to learn how to test your horse for signs of neurological behavior, check out this video on my YouTube channel. It will help you rule out some things.

Until next week,

~Tony

P.S. While you’re watching that video, make sure and subscribe to my YouTube Channel. It’s got a lot of great content, and subscribing will get YouTube to tell you when I post a new video. It also makes me feel good to see how many adoring fans I have. Hey, I’m a cat! Collecting fans is mostly what we do. That, and sleeping, which I’m off to do now.