“Have you ever heard of Cushing’s disease in dogs?” I asked my new veterinary client, the proud owner of a 15-year-old Lab.
Sitting on the floor of the exam room with me,
As I was rubbing her Lab’s belly, I sensed my client’s fear and worry. I had just met her dog forty minutes prior, listened to the 15-year-old dog’s health history, read through 32 pages of medical history, and was now conducting the physical exam.
Now we were discussing Cushing’s disease in dogs. I suspected her canine companion had this condition too. I sincerely apologized for overwhelming her, but she smiled and said, “I appreciate it! I’m glad there are people like you who can help and who find this so interesting.”
I laughed. Cushing’s disease in dogs (also known as hyperadrenocorticism) is not necessarily what I’d call interesting, but because this syndrome is fairly common in senior dogs (who make up the majority of the patients in my practice), it is critically important to me. And if you have a senior dog, it may be important to you.
What is Cushing’s disease?
In the most basic terms, Cushing’s disease occurs when the body produces too much stress hormone, called cortisol. Cortisol is the body’s natural steroid and is absolutely essential for day-to-day life. The body regulates cortisol levels very carefully. When cortisol gets out of whack, bad things can happen!
The end result is too much cortisol. This is the case in about 80% of dogs with Cushing’s disease. In the other 20% of dogs, a tumor grows on the adrenal gland. (These are small, bean-shaped organs found just above the kidneys.) However, the end result is essentially the same. These tumors also lead to elevated levels of cortisol in the body.
Playing the odds, I suspected my Lab patient had a small brain tumor called a pituitary microadenoma.
But let’s back up for a second. Why did I suspect Cushing’s disease in my patient? In my discussion with the dog’s owner, she had mentioned increased thirst, urination, and panting. These are three cardinal symptoms.
And while I spoke with her, I sat rubbing the thin skin of the dog’s pot belly. (Yes, cardinal symptoms number four and five.)
Symptoms of Cushing’s disease in dogs
If you have ever taken a steroid (for example, prednisone) for a medical condition, you may have felt restless or had an increased appetite. The symptoms of Cushing’s disease in dogs are similar to some of the side effects experienced by human patients who are taking steroids.
Symptoms of Cushing’s disease in dogs include:
- possible behavior changes
- increased drinking and urinating
- increased appetite
- weight gain.
Also, dogs with Cushing’s disease are prone to infections. Mostly, these manifest in recurrent skin infections (called pyoderma) and urinary tract infections.
Other noticeable signs of Cushing’s in dogs include:
- a pot-bellied appearance
- thinning skin
- muscle wasting.
Because of the loss of muscle mass, a dog with arthritis might suddenly worsen. Additionally, hair may fall out, and a dog may suddenly have skin changes like a teenager!
Diagnosing Cushing’s disease in dogs
I recommend that my client starts with a simple test called a urine cortisol creatinine ratio (UCCR). This is an interesting test (okay, maybe I do find all this interesting!) because it’s collected at home and rules OUT the diagnosis, rather than ruling it IN. Let me explain…
Testing to rule OUT Cushing’s
First, the test measures cortisol in a urine sample. Cortisol is the hormone “over produced” in Cushing’s syndrome, but animals and people naturally produce it as part of a healthy response to stress. For best results, the urine sample is collected at home. This way, the dog doesn’t get anxious from a visit to the veterinary clinic, secrete a bunch of cortisol, and skew the results.
Second, the test doesn’t prove that a dog has Cushing’s disease. On the contrary, all it can tell us is that a dog does NOT have Cushing’s, thus ruling OUT the diagnosis.
This may seem counterintuitive, but it’s actually quite valuable. Granted, if the results are elevated, more tests will be required because Cushing’s was not confirmed but remains likely. If the UCCR is normal, we can cross Cushing’s off the list as a possible diagnosis and move on.
Testing to confirm Cushing’s disease
Tests to rule IN Cushing’s (aka confirm the diagnosis) are blood tests. There are three options: the ACTH stimulation test, a low dose suppression test, or a high dose suppression test. Your veterinarian may also ask for a urine sample to look for evidence of urinary tract infection, which can be “silent” and accompany Cushing’s disease, especially in female dogs.
Sometimes the results are still not conclusive, and in order to nail the diagnosis, abdominal ultrasounds, urine cultures, X-rays of the chest, further bloodwork, and more tests may be recommended.
Cushing’s disease treatment options
Of course, my client’s next question was, “What happens if my dog is diagnosed with Cushing’s?”
I explained that diagnostics were the next step and we shouldn’t jump to conclusions. But to address her question, I did explain a bit about how Cushing’s is managed. In most cases, Cushing’s is a lifelong disease. Treatment requires careful monitoring with your veterinarian. It is a commitment and it can be daunting. However, there are many treatment and management options.
Managing Cushing’s with medication
Since over 80% of dogs diagnosed with Cushing’s disease have tumors in their brain that are very small, management with medication is usually the preferred route.
Vetoryl® (trilostane) is currently the only veterinary approved product on the market that treats both pituitary and adrenal-dependent forms of the disease. Another drug, called Lysodren® (mitotane) targets the adrenal glands, (which are over-producing cortisol) and inhibits them. Dogs taking medications such as Vetoryl® must be monitored very closely (with frequent lab work) because the medication can work TOO well and cause the opposite condition—hypoadrenocorticism (aka Addison’s disease). Follow-up bloodwork with your veterinarian will be necessary. In the interest of full disclosure, this can represent a significant financial and time commitment.
For more information on the treatment of Cushing’s disease, specifically how the medications work, please read this article by Veterinary Partners: Treatment of Pituitary Form of Cushing’s Syndrome.
Selegiline and off-label medications
Also, Selegiline is approved to treat Cushing’s disease, but only in the case of pituitary tumors. There are other, off-label medications such as mitotane and melatonin. However, these are not approved and must be used with care and with the understanding that they may not be effective.
When surgery is necessary
If an adrenal tumor is the cause of the Cushing’s, the affected gland can be removed through surgery. It is not a simple surgery and is ideally performed by a board-certified surgeon. Risk of hemorrhage is significant. Thus, many owners opt to treat their dogs with medical management to avoid the cost and risk of surgery.
How to comfort a dog with Cushing’s disease
What else can you do to help?
- Always have fresh water available. Cushing’s causes
increased thirst and urination, so your dog will want to drink more and need to go out frequently for potty breaks.
- Keep a vigilant eye out for signs of skin and urinary tract infections, which should be promptly treated. Your veterinarian
may prescribe antifungal and antibacterial shampoos and wipes to proactively help combat skin infections.
- Watch for signs of urinary issues such as increased frequency of urination, foul odor to the urine, straining to urinate, and/or blood in the urine. If you observe any of these signs, take your dog to your veterinarian. For dog’s with Cushing’s, urinary tract infections are nearly impossible to prevent.
Addressing mobility issues due to Cushing’s disease
If your dog is having mobility issues due to muscle wasting, look for options to minimize discomfort and falling. Keep your dog on
I’ve had several patients with muscle wasting due to Cushing’s syndrome thrive using ToeGrips. The non-slip grips fit on dogs’ toenails to improve traction on hardwood floors, preventing sliding and falling.
As the founder of Dr. Buzby’s ToeGrips for Dogs, I often hear from customers who share ToeGrips success stories. One of our customers wrote to let us know that her dog, Brew, a 14-year-old Bichon mix with Cushing’s syndrome, saw an immediate improvement in his mobility with the addition of ToeGrips.
Other ways to improve your dog’s mobility are:
- soft bedding (consider a memory foam dog bed)
- avoiding stairs
- therapeutic laser and physical therapy
- teaching your dog to use ramps.
If your dog has been diagnosed with Cushing’s disease, there is hope!
Cushing’s disease in dogs is not a hopeless diagnosis! But it IS a disease that requires careful and observant monitoring, both by you and your veterinarian. Regular veterinary checks with bloodwork and urine testing should be expected. Despite all this, a dog with Cushing’s disease can have an excellent quality of life and live to a ripe old age!
I’m optimistic that my sweet senior Lab patient has many happy years ahead. I look forward to partnering with his mom to provide him the longest, healthiest life possible through appropriate veterinary diagnostics and treatment.
What questions do you have about Cushing’s disease in dogs?
Please comment below.