Cushing’s Disease – Symptoms, Causes and Treatment

Picture of an older dachshund

Hyperadrenocorticism, also known as Cushing’s disease, is a medical condition where the dog’s body produces too much cortisol. It shows up more or less commonly in middle-aged to older dogs.

A dog’s body requires some steroids for everything to function adequately. These are produced by the adrenal gland, located in the close proximity of the kidney. The pituitary gland is in charge of sending out messages to the adrenal gland so that the second produces steroids in a balanced way. Whenever a dog gets a growth on any of these glands, he or she will suffer a variety of symptoms.

In this article, we’ll look at some of the typical clinical signs that characterize Cushing’s disease, how it affects your dog, how it can be diagnosed, and whether or not there are any risk-free treatment options.

How Does Cushing’s Disease Happen?

There are three main types of Cushing’s disease, and the most common one is represented by a pituitary gland tumor. This happens in about 85% to 90% of all cases. Whether the tumor is benign or malignant, it can cause an overproduction of a hormone (ACTH) which stimulates the adrenal glands to produce too much cortisol.

An adrenal gland tumor is the next possible cause of a case of Cushing’s disease. In most cases, if it is benign, surgery can be used to remove it and therefore, cure the medical condition. If it is malignant, an operation might help for some time, but the prognosis is overall less favorable.

Finally, excessive use of cortisol caused by prolonged treatment with steroids is the last possible cause of this disease. Fortunately, the percentage of these cases has decreased significantly over the years as veterinarians are prescribing fewer steroids and usually for limited amounts of time.

What Are the Signs of This Disease?

No matter the type that a dog is suffering from, the symptoms of Cushing’s disease are usually the same. The most common ones consist of an increase in appetite, urination, and water consumption. Cortisol stimulates appetite, so if you notice that your dog is wolfing down his or her food and water like there’s no tomorrow, maybe it’s time to take your pet to the vet.

In most cases, though, what pet owners notice first are excessive thirst and urination. Dogs can also experience hair loss, panting, weight gain, skin changes, abdominal swelling, and a general lack of energy. Some dogs can start having lowered immunity and as such, become exposed to a variety of common diseases.

Getting a diagnosis can be more or less challenging, as in most cases, the symptoms are rather mild. Therefore, extra tests are always required to determine your dog’s cortisol levels.

Diagnosis and treatment of Cushing’s Disease

The two most common tests that are used to detect Cushing’s disease are the ACTH stimulation test and the low-dose dexamethasone-suppression test (LDDS). A variety of other tests can be performed and can help determine the exact type of medical condition. Naturally, an abdominal ultrasound is also required and can be an important part of the diagnostic process as it allows the veterinarian to assess the size of the adrenal glands, as well as whether or not there is any tumor growing on them.


The treatment largely depends on the type of Cushing’s disease that the dog is suffering from.

In cases where a pituitary tumor is at the root of the problem, the treatment is most complicated. There are two drugs commonly used to treat the disease (trilostane and mitotane) and what the treatment aims to do is to allow the pet to live a happy and normal life for many years as long as they stay under close medical supervision. However, if the pituitary tumor grows, it can affect the brain, which results in neurological signs.

If an adrenal gland tumor is discovered, it requires abdominal surgery. In cases where the whole tumor is removed and it is not malignant, the dog has a good chance of regaining his or her full health. In cases where surgery isn’t possible for some reason or another, some patients can be managed with medication.

If the disease was caused by excessive use of corticosteroids, the discontinuation of the treatment is necessary right away. However, it should be done in a gradual manner so that no complications ever occur. Talk to your vet about what other treatment options are available for your dog because most of the time, the condition that was being kept under control with the help of steroids will reappear if they are discontinued.

Drugs and Their Side Effects

According to the U.S. Food & Drug Administration, Vetoryl (trilostane) can be used to treat both adrenal- and pituitary-dependent Cushing’s disease in dogs. It works by stopping the production of cortisol in the dog’s adrenal glands. However, it should not be given to canine patients that take medications to treat heart disease, dogs that are pregnant, or dogs that have kidney or liver disease.

Some common side effects of this medication are poor appetite, lack of energy, weakness, diarrhea, and vomiting. Other, more serious adverse reactions include bloody diarrhea, the destruction of the adrenal gland, and sodium and potassium imbalances. Treating Cushing’s disease can also be done by using Anipryl (selegiline), another FDA-approved medication – however, in this case, it only works in pituitary-dependent cases.

Managing a Patient with Medication

Without a doubt, your vet is going to outline a treatment plan for your dog’s specific condition. The guidelines must be followed closely, and the treatments depend on regular and consistent administration of the medication. In many cases, lifelong treatment is necessary.

While most dogs can be treated with minimal or few side effects, the most important thing to keep in mind is that your canine friend has to be kept under observation thanks to regular blood tests. The correct dosage of the medication should be established after your dog starts receiving the drugs, so taking your pet to the vet’s office is crucial to ensure that you give him the right dose.



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