Many pet parents don’t realize that their dog has Cushing’s disease, at least not initially, because they don’t seem particularly unwell. In this article, we’ll explain Cushing's disease, outline the symptoms, and share information on how it's diagnosed and treated.
Breeds commonly affected:
Miniature and Toy Poodle
What is Cushing’s disease in dogs?
Cushing's disease is a hormonal condition that occurs when the adrenal glands release too much stress hormone, cortisol, into the blood. Its technical name is hyperadrenocorticism. In most smaller dog breeds, like Miniature Poodles and Yorkshire terriers, it’s caused by a microscopic tumor in the pituitary gland of the brain, called a microadenoma. Thankfully, this tiny tumor is just a cluster of cells, so it doesn’t cause the symptoms or poor prognosis you’d normally expect with a brain tumor. Instead, the cells in the pituitary gland release too much adrenocorticotrophic hormone – a chemical signal that tells the adrenal gland to release cortisol.
Cushing’s disease can also be caused by a tumor on the adrenal gland, and this is more common in large-breed dogs. The adrenal gland tumor makes the adrenal gland overactive, producing too much cortisol.
Finally, Cushing’s disease can also be caused by medication, with long-term doses of steroids mimicking excess cortisol.
What are the symptoms of Cushing’s disease in dogs?
The symptoms of Cushing’s disease in dogs include:
Drinking a lot of water
Passing urine a lot
Increased appetite
Panting
Thin Skin
Hair loss or thinning of the fur
Pot-bellied appearance
Lethargy or lack of energy
How is Cushing’s disease diagnosed?
If your vet suspects your dog has Cushing's disease, they will likely recommend a blood test as a first step. This blood test will give an idea of your dog's overall health and rule out other potential causes of the symptoms, including diabetes and kidney disease. For the same reason, the vet might test the concentration of your dog's urine and check it for glucose and protein. If they suspect Cushing's based on the blood and urine results and your dog's symptoms, they’ll likely perform an ACTH stimulation test, a series of blood tests before and after an injection of a synthetic hormone that behaves like the adrenocorticotrophic hormone. If the blood test shows that the adrenal glands have responded excessively to the hormone injection, then Cushing's disease is likely.
If your dog's ACTH stimulation test results are normal, but the vet still suspects Cushing's, more sensitive tests can be performed, including a longer series of blood tests, a urine test, and advanced imaging like CT and MRI scans.
How is Cushing’s disease treated in dogs?
Cushing’s disease in dogs can be treated medically, usually with trilostane or mitotane. These medications reduce the amount of cortisol produced by the adrenal gland, reducing the symptoms over time. It’s really important that the dose is increased slowly and that dogs receiving treatment have regular blood tests to ensure that the dose is right. If the amount of cortisol produced by the adrenal glands drops too low, it can cause a serious condition known as Addison's disease, which can be fatal.
What is the prognosis for Cushing’s disease in dogs?
Although there are some side effects associated with the medication to treat Cushing’s (including vomiting and diarrhea, weakness, and lethargy), most dogs can be stabilized on a long-term dose with regular monitoring. Therefore, although Cushing’s cannot be cured, with treatment the prognosis is usually good.
Can Cushing’s disease be prevented in dogs?
Sadly, Cushing's disease cannot be prevented, and any dog can be affected. However, if you're familiar with the symptoms, you'll be able to spot them as soon as possible, meaning your dog can start treatment early.
Conclusion
Cushing’s disease affects dogs as well as humans. It causes symptoms including increased thirst, urination, and appetite, and left untreated it can lead to health problems like diabetes and congestive heart failure. Thankfully, with the correct treatment and ongoing monitoring, dogs with Cushing’s can have a good quality of life.
About the Author
This blog post was written by Dr. Hannah Godfrey, a seasoned veterinary professional who earned her degree from the Royal Veterinary College in 2011. Her career has spanned various aspects of animal care, from mixed practice to specialized small animal work in a bustling hospital setting. Along the way, she even honed her skills with advanced training in canine and feline dentistry! These days, Dr. Godfrey focuses on sharing her expertise through pet-related writing. Learn more about her background and qualifications on petsradar.com.
Hannah graduated from the Royal Veterinary College in 2011 and began work straight away at a busy mixed practice. Initially, she treated all species, but focused on small animals from 2014. She has a passion for soft tissue surgery, ultrasound, and canine and feline dentistry, having completed additional training in these areas.
In 2018, Hannah began working at a smaller, independent practice close to home, in order to devote more time to her other loves – writing comedy fiction and spending time with her young family. She now spreads herself across clinical and non-clinical veterinary roles, including working as a locum vet, being Community Lead for a team of Human Factors trainers, and using her writing skills to help educate and inform pet owners.
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