By Popular Demand, Some Information About Cushing's

A stereotypical Cushing's pony

A few of you fine people asked for more information on Cushing's Disease after my recent post, and I'm here to quench your thirst for knowledge.

Cushing's Disease, also sometimes called PPID, is a condition that affects the pituitary gland. (Fun fact, dogs and humans can also get Cushing's.) The pituitary is located at the base of the brain, and its main function is to control the body's hormones. When the pituitary gets out of whack, whether due to a tumor pressing on it or plain old dysfunction, it negatively affects the whole body. While most often seen in elderly ponies and older horses (18-20 years and older), it can strike horses as young as 7. Dino was just 13 when he was diagnosed.

This is a human brain, but you get the idea. Tiny little gland. 

In horses, hormones control a lot of really important functions. Some of those include regulating shedding and hair growth, sweating, the production and maintenance of muscle and fat, and even immune system function. So you can start to see that a pituitary gland misfire would cause a whole lot of problems.

If not treated, Cushing's Disease wreaks havoc on a horse's hormonal system. Symptoms of Cushing's include, but are not limited to:

-Inability to shed the winter coat completely, or at all. This is the hallmark symptom of Cushing's Disease. Horses with advanced Cushing's are characterized by their long, shaggy coats that refuse to shed. However, some cushingoid horses don't look like a Rastafarian yak, but still have abnormal shedding patterns. Dino was in this second category at the time of diagnosis.

-Abnormal sweating. In most cushingoid equines, this symptom manifests itself as excessive sweat production. They will be drenched just standing in their stalls doing nothing. However, abnormal sweat patterns can also present as the inability to sweat adequately, also known as anhidrosis. Dino was anhidrotic when I first adopted him and couldn't sweat enough to keep himself cool. This is a very, very scary condition and not one I would wish on any horse owner.

-Loss of muscle and condition. This symptom can start out very, very subtly. Owners might notice a loss in topline muscling, the horse might look a bit thinner than normal, and the horse will just look a bit "old". As the disease progresses, muscle wasting will become more evident. What I first thought was just the result of a tough winter was actually a symptom of Cushing's.

-Abnormal fat deposits. This is one of the weirder symptoms. Cushing's Disease causes the body to produce these bizarre fat pads in random places on the body. The hollows of the eyes will fill in with fat, and oddly-placed patches of fat will appear on a horse with not enough fat on its frame where it should be.

-Excessive thirst and urination. Cushingoid horses will often be peeing all. the. time. And drinking a TON. A huge pain in the ass if you are the one cleaning the stall.

-Laminitis and founder. These two are the absolute most major concerns for owners of horses with Cushing's. The dysfunction of the pituitary gland hampers the body's ability to digest and metabolize sugars, which as we all know can lead to laminitis and founder. This is why appropriate diet and weight management are SO important in dealing with this disease.

-Frequent abscesses and trouble healing from wounds and infections. Cushing's Disease impairs the immune system, so affected equines often take longer to heal and are more prone to hoof abscesses. Vaccines should also be spread out over a couple days so the immune system is stressed as little as possible.


So, given the range of absolutely horrible symptoms associated with this disease, how do we diagnose and treat it?

The gold standard in Cushing's diagnosis is the ACTH test. ACTH is a specific hormone that is produced in excess in cushingoid horses, and can be detected in the blood. Testing should ideally be done in the springtime, as natural hormonal changes in the fall can cause a false positive. I had Dino tested in June, and his ACTH level was just over the line into Cushing's territory.

While there is no cure for Cushing's, it can be treated and managed. There is only one drug available that is proven to treat this disease, and that is Pergolide. In recent years, drug companies began making Pergolide in a more stable, easy-to-administer pill form known as Prascend. Dino gets one Pracend pill per day, and it costs me about $70 a month. Not cheap, but it works.

In addition to medication, the right diet is absolutely CRUCIAL to successful management of a horse with Cushing's. These horses cannot. metabolize. sugar. They just can't. A diet full of starch-heavy grain, heavy grazing on rich grass, and sweet treats will literally kill your cushingoid horse, and severely founder them at the very least.

If the horse in question is an easy keeper, they should ideally be sustained on hay and a handful of ration balancer. That's it. No treats, no sweet feed, no grazing. Cushing's horses NEED to be muzzled when out on pasture, or kept in a dry lot. Dino is a performance pony, so he needs some extra calories. I have him on about a pound per day of Nutrena Safe Choice Special Care, which is a low-starch grain specially formulated for horses with metabolic disorders. Alfalfa cubes, rice bran, and unsweetened beet pulp can also be good choices for horses that need a few more calories. Cushingoid equines should never be allowed to get overweight. This increases the risk of laminitis and founder tenfold. If you keep your horse at a boarding barn, it's imperative that everyone knows that your horse is not to get ANY treats, ever. "Safe" treats for Cushing's horses include sunflower seeds, peanuts, celery, and watermelon. There are also a few Cushing's-safe horse cookies on the market now as well, but I haven't gotten around to buying any.

Now that I've completely terrified you, let me say that with Prascend and a good diet, Cushing's Disease is absolutely manageable. Looking at Dino today, 3 years post diagnosis, no one would ever guess he has Cushing's. His only remaining symptom is that he sheds out a little slower than the average horse. But he's in perfect weight, has great muscling, sweats normally, and is for all intents and purposes a completely healthy, happy pony. We ride, we compete, we train, we have fun. And I'm confident that with continued management and treatment, my little buddy will live long into his golden years.