A Cushings Comparison

Josh - April 11, 2009 - before being given pergolide to manage his Cushings

Josh's coat, at this time, was very patchy with areas of very long hair, most noticeable here along the bottom of his rib cage and as what looks like feathering on his forelegs.

Josh began taking pergolide in June 2009.  Below is a photo taken March 17, 2010.  His coat is still very thick, but of a much healthier texture and consistent length.

We will retest Josh's ACTH level in June to determine if his pergolide dose needs any adjustment.

Aha! Its NOT Just Our Imagination!

TREES current herd consists of 7 horses with confirmed Cushings, or PPID, diagnoses, and at least 3 other horses than show some symptoms, but had "normal" ACTH levels when tested.  Several times, we've discussed with our vet the possibility that the parameters defining "normal" may need to be re-evaluated.  If we had several horses showing clinical signs of PPID even when testing as Normal, it is likely that other owners experience the same thing.

Now, from the Jan2, 2009 horse.com article, "Equine Endocrine Disorders Discussed at AAEP," we see:

"It was pointed out that PPID is difficult to detect in its earliest stages, while advanced disease is relatively easy to recognize. The two most commonly used tests for PPID--resting adrenocorticotropin hormone( ACTH) concentrations and the overnight dexamethasone suppression test--can be used to confirm the diagnosis. However, these tests are less likely to yield positive results when PPID is first developing, so clinical judgment must be relied upon in these cases."

So, it's not our imagination.  Some horses exhibit clinical symptoms even though the test results do not confirm the diagnosis.

Fortunately,

"New diagnostic tests are being developed for PPID and might allow earlier detection of the disorder. These include the combined dexamethasone suppression/thyrotropin-releasing hormone (TRH) stimulation test, TRH response test (with ACTH concentrations measured 10 and 30 minutes post-injection), and oral domperidone challenge test."

It may seem odd to be so excited about these little advances but, considering that ten years ago Cushings was often viewed as a terminal illness, these "little" things can mean a lot to people caring for long-time equine family members.  The sooner a PPID patient is started on treatment and modified management techniques, the better the chances of preventing serious complications, which translates into a better long-term prognosis.

TREES' Cushings Club

I just realized we frequently talk about our Cushings Club, but we've never really told you who the members are.  The official membership stands at six, but last summer's testing revealed two more may be at the jumping off point.  As we mentioned a few days ago, our new arrival, Sherman, looks pretty suspicious as well.  Not long ago, a diagnosis of "Cushings Disease," now known as PPID (Pituitary pars intermedia dysfunction,) was viewed by many as a death sentence.  Not any more!

And so, without further ado...........The Traveller's Rest Equine Elders Sanctuary Cushings Club:

Nate, mid 30's

Freddy, 26

Wade, 26

Sonny, 38

Josh, late 30's?

Henry, 25

Interestingly, all are geldings.  All are managed with pergolide and a carefully controlled diet (thank to all of our visitors for being very understanding about our "No Treats" policy,) and all are retested each year with pergolide dosages adjusted accordingly. 

Freddie, the Self-Cleaning Arabian

Thank Goodness. Freddie really is self-cleaning most of the time. We're on our way to a record number of consecutive rainy days (or so the local weather gurus "joke.")

Even so, look at our 26 year old Arabian gelding, Fred Astaire:

Photo courtesy of Molly McDonald Peterson, mJm photography

No kidding! This is Freddie, as is, no special grooming, bathing, or "photoshopping," after several days of rain and mud. What a good guy.

We also have to take the opportunity to point out that Freddie is one of TREES' Cushings patients. Freddie's symptoms have been controlled for three years now, using dietary management and Pergolide. Again....Thank Goodness! Can you imagine dealing with an almost white "Cushings coat" during mud season? We don't even want to think about that prospect.

More thoughts on pergolide

After an earlier post about the stability of compounded pergolide, a few other points we thought worth mentioning came to mind:

One is that there is no "standard" dose as there is for most other meds. In other words, there is nothing that says every horse should receive X mg/100 lbs body weight. It varies from horse to horse. If your starting dose doesn't seem effective, your vet may want to recheck ACTH levels and adjust as needed. We've had to adjust 2 or 3 times on some horses to get it right, waiting at least a month or more between the time we change dose and the next test. Pergolide is not one of those things that works overnight.

Second, be sure you know what concentration your pharmacy sells. We've had some pergolide that was 1mg/ml, meaning the horse gets 1 ml of liquid to get 1mg of the drug. We've also had some that was 0.25mg/ml (4 ml liquid = 1mg of drug) and now use 0.20mg/ml (5 ml of liquid = 1 mg of drug.) One advantage to the more dilute form is a lesser difference in dose if you don't measure to the exact hair.

Finally, *when* you test ACTH levels has an effect on results. ACTH naturally increases as winter approaches and is lower in summer, so season will affect your test results.. Some people compensate by giving a different dose of pergolide in the winter than in the summer. We haven't done that, but it is something to be aware of.

Is Your Horse's Pergolide Stable?

Long before it became a preferred treatment for equine Cushings, pergolide was used to treat Parkinson's Disease in humans. Serious side effects, however, led the FDA to remove pergolide from the market for human use in 2007. Since then, only certain forms of pergolide have been available for use in horses, but they had not been evaluated for stability, among other things.

Stability and Efficacy of Compounded Pergolide Examined outlines a few recommendations, based on findings of a study conducted at the College of Veterinary Medicine at North Carolina State University:

>Store compounded pergolide mesylate products in a dark container, protected from
light;
>Refrigerate products to help minimize excessive degeneration;
>Dispose of products within 30 days from date of compounding;
>Evaluate the color of the product prior to each use and discard any pergolide product that has undergone any change in color, and;
>Request that your pergolide is compounded by pharmacists that use only the officially recognized formula (by the United States Pharmacopeial Convention).

Based on comments by a regular TREES visitor, these suggestions do seem to have a big impact on how well pergolide works. Here, we only purchase two weeks worth of pergolide at a time from a pharmacy that does not compound the drug until it is ordered and it is always kept refrigerated. Our visitor has mentioned that other farms using different forms of pergolide or different storage techniques seem to see more obvious symptoms than we see here. That is far from scientific proof, of course, particularly since each Cushings patient may exhibit different symptoms to varying degrees and may respond to treatment differently than other horses. We know we are paying more for our pergolide than some other people, but it may be worth the extra expense if quality treatment helps to prevent serious complications such as laminitis.

When visiting the link to the article, please also pay attention to the sidebar concerning "Human Health," particulary if you are using pergolide powder:

In response to the demonstrated stability concerns of liquid pergolide products, there has been some discussion regarding the use of bulk pergolide powder in equine practice. According to pharmacists, this is not a realistic alternative to the, "pergolide problem" as inhalation or ingestion of pergolide mesylate by humans is unsafe. In particular, inhaled or ingested pergolide can cause damage to the central nervous system and cardiovascular system (heart and lungs).

PPID (aka Cushings)

Traveller's Rest is currently home to three horses and one pony with confirmed diagnoses of PPID, or Pituitary Pars Intermedia Dysfunction (commonly called "Cushing's Disease," or "Cushing's Syndrome.")


Researchers have found that horses with PPID have very few dopamine-producing neurons in the pars intermedia. Since dopamine inhibits the production of hormones by the pars intermediate, its absence allows excess hormone production which leads to the classic symptoms associated with Cushings.


While dietary management and supplements help control symptoms resulting from high insulin levels, and Trilostane can directly inhibit the production of cortisol, only one medication in current use addresses the dopamine deficit, believed to be the root cause of the problems.


That drug is pergolide mesylate, a medication originally prescribed for human Parkinson's patients. Upon diagnosis, all PPID horses at TREES are started on Pergolide.


Below is Oracle, diagnosed with PPID, but not yet started on treatment in this photo:



Freddie, on the other hand, has been on Pergolide for two years:
Symptoms of PPID are many and varied, though not every horse will have every symptom. Some things to watch for:

• prone to laminitis
• gains weight easily
• cresty neck
• unusual "fat pads"
• muscle wasting
• "pot belly"
• problems with thermoregulation, especially in warm or hot weather
• abnormally long, curly hair coat, year-round
• suppressed immune system
• excessive thirst and urination
• irritability in a previously good-natured horse
• occasionally, neurological complications