Cushing’s disease – Clinical Signs

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Dogs with Cushing’s disease have a wide range of signs, including infections, increased thirst, urinary accidents, and many more. Join special guest Dr. Amy Oberstadt, veterinary internal medicine specialist, in the first of our three part series on Cushing’s disease to learn more about this hormonal disease that can cause major quality of life issues in our pets.

Introduction - What's going on with Russell Sprout?

[00:01:05] Dr. Lancellotti: Welcome everyone to Your Vet Wants You to Know. We have a very special series of episodes coming up. With me today is a very special guest, Dr. Amy Oberstadt. Dr. Oberstadt is a board certified small animal internal medicine specialist who has lived and practiced across the United States. She is currently a private practitioner in Texas, but she has spent the last five years in Michigan, including completing her residency at Michigan State University. Prior to that, she was my classmate at Western University of Health Sciences. She absolutely loves to travel and her favorite diseases to manage are endocrine or hormonal diseases. She has a soft spot for geriatric cats. Thank you very much for joining us today, Dr. Oberstadt. 

[00:01:50] Dr. Oberstadt: Thank you very much, Dr. Lancellotti. I know we’re not going to be tackling geriatric cats today, but Cushing’s disease is near and dear to my heart as well. 

[00:01:59] Dr. Lancellotti: Awesome. I’m really excited to do this with you and talk to pet owners about Cushing’s disease over the next few episodes. So can you tell our listeners what’s going to be happening?

[00:02:09] Dr. Oberstadt: For the next few episodes, we’re going to be talking about a common hormonal disease in dogs that’s called Cushing’s disease. Cushing’s disease, or hyperadrenocorticism, is a disease that is commonly encountered by both dermatologists, like yourself, and internists, like me. So we thought it would be really interesting to talk about this disease from both of our different perspectives, as well as the personal perspective that it has for you and Russell Sprout.

[00:02:35] Dr. Lancellotti: Yeah, I’ve been really looking forward to this because Cushing’s disease is a really fascinating disease to diagnose and treat as a veterinarian, but it also has a personal place in my heart, as you know, because I diagnosed my dog, Russell Sprout with Cushing’s disease recently. Russell Sprout, for our listeners, he is that scruffy mutt on the Your Vet Wants You to Know logo. Many of the listeners will know from the episode on environmental allergies, that Russell Sprout has been an allergic dog since he came into our family. I’ve been managing his allergies for many, many years, but over the past year, he started developing ear infections, which he’d never done before. So his allergies had always really been focused on his paws and not so much his ears, which it can be for some allergic dogs. My husband and I also noticed that one of our three dogs, we weren’t sure which one at the time, had been having accidents in the house overnight.  Generally I try and do blood work on all of my dogs every six to eight months as part of their preventative health care, especially now that all three of my dogs are senior dogs. Around that same time those ear infections and the accidents in the house were happening, Russell Sprout also had an increase in his liver enzymes on his blood work. So all of these little things that were happening were sending up little red flags to me telling me that I needed to test him for Cushing’s disease and sure enough, that’s what we were dealing with. 

[00:04:01] Dr. Oberstadt: Yeah, he sounds like a postcard perfect Cushing’s dog. I think it just highlights that these are all very subtle signs. Having you guys notice the increased water consumption, urination, the elevated liver enzymes, and these are things that seem completely unrelated when looking from the outside in. So for today’s episode, we’re going to unravel for you guys exactly what Cushing’s disease is and how these clinical science can start to tie together. We’ll talk about what clinical signs a dog would have that would make your veterinarian suspicious of this disease. In the next episode, we’re going to talk more about these tests that are available as well as some of the pros and cons of each test. Finally, in the last episode for this series, we will discuss the treatment options that are available for Cushing’s disease.

What is Cushing's Disease?

[00:04:49] Dr. Lancellotti: This is great. I really hope that pet owners can use these episodes as a resource to help them to understand this disease because it is complicated and how Cushing’s disease affects their pet, but more importantly, enable them to more effectively communicate with their family veterinarian about what their concerns are and what they’re seeing with their pet at home. It’s definitely one of those diseases that requires a lot of teamwork between the veterinarian and the pet owner to effectively manage the pet. It can be hugely rewarding for everybody involved. So let’s start by giving pet owners a breakdown of what Cushing’s disease actually is. 

[00:05:27] Dr. Oberstadt: Cushing’s disease is an overproduction of the body’s natural steroid hormone, which is called cortisol. Cortisol’s main function is as a stress hormone in your body. So in stressful situations, your cortisol rises in order to help your body focus on that stress response. As a consequence of focusing on the stress response, your body stops focusing on some of its normal maintenance things. So we’ll see weird clinical signs that don’t always seem like they have a lot to do with each other, but are commonly seen with stress. We’ll see things like increased panting, we’ll see increased hunger so they can keep this stressed level of energy that’s really high, and we’ll also see stranger things like increased thirst and urination. When we start looking a little deeper, we’ll see elevated liver values, and we’ll also see infections of the skin, ears, and urinary tract. As stress hormone levels persist over time, these pets start slowing down and so their muscles get weaker. They start getting this almost potbellied appearance and because cortisol affects so many body systems, dogs can have a wide range of clinical signs that really look like they’re slowing down. Often we see these patients just seem like they’ve aged 10 years over a six month period of time. Once we start putting all of these things together, we start saying, “Hey, maybe these things can point us towards this cortisol level as the ultimate cause.” 

[00:07:01] Dr. Lancellotti: So cortisol is causing all of these things that we’re seeing with the pets, but where does the cortisol come from? Can you kind of take us on a magic school bus type ride into the dog’s body and what’s happening with cortisol?

[00:07:14] Dr. Oberstadt: Absolutely. This is where it gets confusing because cortisol is something that there are multiple places in your body that help control. The cortisol itself is produced by tiny glands that live above your kidneys, called your adrenal glands. Your body has two, one above each kidney. Now the cortisol levels that your adrenal gland is producing comes from somewhere completely different in your body. The adrenal glands are actually controlled by a tiny gland at the base of your brain called the pituitary gland. The pituitary gland is kind of like the air traffic controller of the system. So it’s going to be waving the flags and telling your adrenal glands what to do. In 80% of dogs that have Cushing’s disease, the air traffic controller, or the pituitary gland has developed a little bit of hyperactivity. So usually this is actually a small tumor, which sounds really scary, but it’s so small it doesn’t cause your body a lot of problems. That has told both of your adrenal glands to start producing way too much cortisol. In less common cases, we’ll see that the adrenal gland itself is the problem, and that’s where one adrenal gland has become much larger than the other. So that adrenal gland is what’s responsible for the Cushing’s disease in your body. Thankfully, we have a lot of different ways to help you to differentiate between those disease processes and we’ll talk a lot more about those in the second episode.

[00:08:48] Dr. Lancellotti: I love that air traffic controller analogy. I think that’s great because really you think about the pituitary gland as this guy out there waving the flags as fast as he can, “More cortisol, more cortisol,” but you don’t really need to be that stressed. So in those patients that have too much cortisol, we need to try and find a treatment that is going to calm that air traffic controller down. I love that analogy. That’s great. 

[00:09:13] Dr. Oberstadt: Exactly, and so we thankfully do have a lot of things in our toolbox to be able to help the body to control that disease process and essentially normalize things again for these dogs.

Cushing’s disease can cause muscle wasting, as seen in the tan dog, whose pot-belly is subtle, and the brown dog, whose pot-belly is more prominent.

Many Different Clinical Signs

[00:09:25] Dr. Lancellotti: So tell me Dr. Oberstadt, as a internal medicine specialist, what types of clinical signs in dogs make you suspicious for Cushing’s disease? What type of pets are coming to you where you are going to consider testing them for Cushing’s? 

[00:09:42] Dr. Oberstadt: Thankfully, most of my cases have already been to their primary vet to help suss out some of these difficult clinical signs.  The most common clinical signs that pet owners are going to see at home and your primary care veterinarian is going to help you recognize, are increased water consumption and urination, increased appetite, a slow progression in this pot bellied look where the skin on the belly becomes thin and dry. Sometimes panting alone will be the biggest concern that they have, and also recurrent urinary tract and skin infections. Once we start digging a little deeper, we will often start getting another hint that something isn’t quite right, because when we talk about the cortisol levels influencing everything in the body, the main organ that is trying to down-regulate that is actually the liver. The liver takes on a lot of stress from all that extra cortisol that’s circulating in the body. One value in particular, the ALP or alkaline phosphatase, is the most commonly elevated lab work value that we’ll see. So most of my cases we’ll usually have at least three of these items that are presenting at home and also have already been to their primary care veterinarian who’s worried that we should pursue an abdominal ultrasound to look at those adrenal glands better and actually make further recommendations based on an ultrasound to help confirm a diagnosis. 

[00:11:17] Dr. Lancellotti: Great, and we’ll definitely talk about the diagnostics in the next episode and what we can do to actually figure out whether or not a pet has Cushing’s disease. I see a lot of the same things that you do, but as a dermatologist, some of the pets that I see are slightly different with their clinical signs of Cushing’s disease. For me, the biggest indicator is the recurrent skin and ear infections, especially in those older animals who have maybe never had problems with their skin and ears before. Many of these pets have been treated as if they have allergies because they’re itchy, but I actually discover the itch is from infections because bacteria and yeast, they can make the dog itchy. So normal allergy medications like Apoquel and Cytopoint that are great for environmental allergies, they’re not really effective treatments for these pets because the infections are still there. Once the infection gets treated, the itch resolves, but without addressing the underlying cause of the infection, those dogs will quickly relapse with infection and then the itch returns. 

[00:12:17] Dr. Oberstadt: Was that something that you guys noticed with Russell at home? 

[00:12:21] Dr. Lancellotti: Yeah, I did actually. When I was treating his ear infections, he was really uncomfortable when the infection was present and I could see there was a lot of goop in his ears. He was scratching at them like crazy. Once the infection was gone, he was totally normal. Like I said before, he had always really been focused on his paws with his allergies and never had ear infections before. During this whole time, the chewing of his paws didn’t change at all. So that was another thing that made me think, “All right, I don’t think this is Russell’s normal allergies. I think there might be something else going on that’s causing him to have ear infections.” 

[00:12:58] Dr. Oberstadt: Yeah, that’s really subtle, but it is often one of the earliest things that we see with these guys.

Excess cortisol with Cushing’s disease can lead to suppression of the immune system, causing infections of the skin, ears, and urinary tract. This dog has large, circular areas of infection on its chest and abdomen.

This dog has developed a pot-bellied appearance, ear infections, skin infection, and paw infections as a result of Cushing’s disease.

Wide range of severity

[00:13:04] Dr. Lancellotti: I can see a lot of other skin changes with Cushing’s disease. Many of those changes I talked about on the steroids episode of Your Vet Wants You to Know when I had Dr. Curtis Plowgian on as a guest. He and I talked about the use of steroids in allergic dogs. When there’s this overproduction of cortisol, we can see things like thinning hair on the dog’s body, because if you’re stressed all the time, who’s going to worry about growing hair. So that hair on the animal’s body gets really thin, but the hair on the head and the legs looks normal, the skin gets thin too On their belly, they can get these little blackheads called comedones. More advanced cases can develop mineral deposits in their skin and those mineral deposits are called calcinosis cutis. These dogs tend to be really heartbreaking. They have really hard calcium plaques that form, usually on the shoulders and the back of the neck.  I have some pretty striking pictures of patients with calcinosis cutis that I’m putting on the website for today’s episode. When you feel those plaques and these dogs, they’re hard, like bone. So it’s really important for us to be able to diagnose Cushing’s disease so we can help these patients. 

[00:14:21] Dr. Oberstadt: Exactly. Sometimes those end up with internal medicine too, because those are often the patients where it’s the hardest to control their disease process. Thankfully, we’ve gotten so much better over the years at catching this disease early, many times before those plaques can form. We do see cases that look really challenging like that, but we’re here to help them too. 

[00:14:44] Dr. Lancellotti: It’s interesting because those cases are definitely more progressed. They’re farther along than some of the early pets that we see with Cushing’s disease. So sometimes for me as a dermatologist, the skin infections are their only clinical signs, the only thing that is indicating to us that Cushing’s disease might be an issue. They don’t always look like this textbook picture that you might see of a dog that has Cushing’s disease, who has that big potbellied appearance with the hair loss on its body, but normal hair and its head and limbs. The pet isn’t always peeing all over the house, like I’m sure a lot of your patients in internal medicine might be. I think most family veterinarians are really good at identifying those progressed cases before they wind up in my hospital. Talking to your family veterinarian about things that you notice that are changing, that might be subtle is important because it might be an indicator that something bigger is going on.

In some dogs, excess cortisol can cause calcium deposits to form in the skin, known as calcinosis cutis. These are thick, hard plaques that most often develop on the neck, shoulders, and groin. 

Good Communication is Key!

[00:15:41] Dr. Oberstadt: Exactly. And one of the reasons that we both feel so passionately about this disease process is there are some cases that will end up needing to see both a dermatologist and an internal medicine specialist. Often it takes a village to treat these dogs too. Once we start recognizing all of these clinical signs and doing all of our general wellness screening, we can really successfully identify these dogs as early as possible to be able to build their team of their family veterinarian, but also the specialists that may need to be involved to help get really sick patients under control. 

[00:16:21] Dr. Lancellotti: This is definitely one of those diseases that requires teamwork from everybody involved. The pet owner and the veterinarian, if there’s a specialist involved as well, everyone should be on board with what’s happening so that they can figure it out together and get the animal more comfortable. So we’ve talked a little bit about what Cushing’s disease is and the clinical signs. Can you kind of wrap that up for our listeners today? 

swollen ear infection in dog with cushings disease

Cushing’s disease can suppress the immune system, leading to infections of the ears (as seen in these two dogs), skin, and urinary tract.

Conclusion

[00:16:46] Dr. Oberstadt: So just to recap what we’ve gone over today, Cushing’s disease is caused by an overproduction of the body’s natural steroid hormone or stress hormone called cortisol. Cortisol is needed to maintain a lot of the body’s normal functions, but, when the body starts making too much, cortisol can suppress the immune system, leading to infections of the skin, ears and urinary tract. Cortisol can also make dogs excessively hungry, thirsty, or have accidents in the house over time. These patients have their muscles weakened, which gives them a potbellied appearance. Because there’s a wide range of body systems that are affected by cortisol, not all dogs with Cushing’s disease will look the same and there can be a wide range of severity to the signs as well. If you and your family veterinarian are suspicious for Cushing’s disease, talk to them about testing  and that’s what we’re going to discuss further on the next episode. 

[00:17:40] Dr. Lancellotti: Yeah, I’m really looking forward to that. So on the next episode, we will be talking about what different types of tests are available. You’ll learn a little bit more about Russell Sprout’s journey with Cushing’s disease and how we wound up with a diagnosis. Dr. Oberstadt will be joining us for the next episode as well. So thank you very much for listening to today’s episode, talking about the clinical signs of Cushing’s disease. 

If you enjoyed this episode, I encourage you to please write a review and subscribe so you don’t miss the upcoming episodes of Your Vet Wants You to Know. Many family veterinarians are very comfortable managing pets with Cushing’s disease, but on the resources page of Your Vet Wants You to Know, I will have links to the American College of Veterinary Internal Medicine and the American College of Veterinary Dermatology, so that you can find either an internal medicine specialist or dermatologist near you, if you would like to consult with a specialist. You can also view the references for today’s show in the show notes, as well as on the episode page of the website. I would invite you to join the Facebook group, Your Vet Wants You to Know, tell us about your pet that has Cushing’s disease. I also love hearing what you would like to learn about on future episodes, so comment in the group, or you contact me through the website. 

The link in this post is an affiliate link. This means if you click on the link and purchase the item, I will receive an affiliate commission at no extra cost to you. All opinions remain my own.

Scratching the Itch:

Ricky Jo, the title character, was a beloved patient of our guest, Dr. Amy Oberstadt. Check out this delightful children’s book in this episode’s “Scratching the Itch” segment.

 

[00:19:02] Dr. Lancellotti: I like to end each episode with a segment called “Scratching the Itch.” The segment highlights something, either a human interest story, a product or website that either provides relief or just makes you feel good. Hence, scratching the itch. If you have something that you would like to be featured on “Scratching the Itch,” please comment in the Facebook group or contact me via the website so we can consider it for something to feature in the future. Dr. Oberstadt, do you have something that scratches the itch for our listeners today? 

[00:19:32] Dr. Oberstadt: I do. What I would like to bring for “Scratching the Itch” today is a children’s book. This book is called “Where will you go, Ricky Jo?” The author is Tom Murdoch. You can find it at a local bookstore or it’s available on Amazon. “Where will you go, Ricky Jo” is a story about an adventurous Chihuahua who is looking to explore the world. This book is near and dear to my heart because Ricky Jo is a patient of mine, so I would love to share this with you. It’s a book that is perfect for young children and my son actually loves those books, so he wanted to share this with everyone. 

[00:20:12] Dr. Lancellotti: That’s awesome. I’ll have to look into that for my two kids, because I’m sure they would love to read about Ricky Jo and her crazy adventures. Thank you Dr. Oberstadt so much for joining us today. 

[00:20:24] Dr. Oberstadt: Thank you so much for having me on the show today. 

[00:20:27] Dr. Lancellotti: I’m excited for our upcoming episodes about Cushing’s disease. Thank you to all of our listeners for listening and I look forward to your next visit with Your Vet Wants You to Know .

References:

  1. Arenas, C., Melian, C., Perez-Alenza, M.D. Evaluation of 2 Trilostane Protocols for the Treatment of Canine Pituitary-Dependent Hyperadrenocorticism: Twice Daily versus Once Daily. J Vet Intern Med 2013;27:1478-1485 
  2. Behrend, E.N.e.a., Diagnosis of Spontaneous Canine Hyperadrenocorticism : 2012 ACVIM Consensus Statement (Small Animal). J Vet Intern Med, 2013(27): p. 1292-1304. 
  3. Bruyette, D. Canine Pituitary Dependent Hyperadrenocorticism Series. 2016. Today’s Veterinary Practice. March/April. 30-38 
  4. Gallagher, A. Hyperadrenocorticism in Dogs. Clinician’s Brief. 2014. Nov. 59-63 
  5. Hoffman, J. M., et al. “Canine Hyperadrenocorticism Associations with Signalment, Selected Comorbidities and Mortality within North American Veterinary Teaching Hospitals.” JOURNAL OF SMALL ANIMAL PRACTICE, vol. 59, no. 11, pp. 681–690. 
  6. Midence, J.N. Cortisol Concentrations in Well-Regulated Dogs with Hyperadrenocorticism Treated with Trilostane. J Vet Intern Med 2015;29:1529-1533 
  7. Nagata, N., Kojima, K., and Yuki, M., Comparison of Survival Times for Dogs with Pituitary-Dependent Hyperadrenocorticism in a Primary-Care Hospital: Treated with Trilostane versus Untreated. J Vet Intern Med, 2017. 31: p. 22-28. 
  8. Reine, N.J. Medical Management of Pituitary-Dependent Hyperadrenocortism: Mitotane vs Trilostane. Topics in Compan An Med (2012) 25-30 
  9. Scott-Moncrieff, J.C. A Compass for Cushing’s: Demystifying Canine Hyperadrenocorticism. 2016. Clinical Brief. 1-12

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