Cortisol is an essential hormone that helps dogs manage stress, regulate metabolism, and fight infections. However, when cortisol reaches excessively high levels for too long, it can lead to some serious health problems and symptoms.
This condition is called Cushing's disease.
Also known as hyperadrenocorticism, Cushing’s disease in puppies is not that common. It mostly affects middle-aged and senior dogs.
It happens when the body produces too much cortisol. Cushing’s disease is progressive, meaning symptoms worsen over time, especially if left untreated.
Fortunately, this condition can be treated and managed. But first, let’s talk more about Cushing’s disease in dogs.
What are the Types of Cushing’s Disease in Dogs?
In a healthy dog, the body carefully balances cortisol production based on what the dog needs. But in a dog with Cushing’s disease, something goes wrong, leading to their body producing too much cortisol for too long.
Cushing’s syndrome in dogs is classified into three categories, namely:
Pituitary-Dependent Cushing’s Disease
This is the most common cause, responsible for about 80% to 85% of all cases. This happens when a tumor forms in the pituitary gland. Although it’s a benign growth, the tumor
The pituitary gland controls many hormones, including adrenocorticotropic hormone (ACTH), which tells the adrenal glands how much cortisol to make.
In dogs affected by pituitary-dependent Cushing’s syndrome, the tumor triggers excess ACTH production, which forces the adrenal glands to overproduce cortisol even though the body doesn’t need it.
Adrenal-Dependent Cushing’s Disease
This type of Cushing’s disease in dogs is less common. Adrenal-dependent Cushing’s syndrome in dogs happens when a tumor forms directly on the adrenal glands. This causes the release of too much cortisol.
These tumors can be either benign or malignant. If the tumor is cancerous, then it can potentially spread to other parts of the body.
Iatrogenic Cushing’s Disease
This form of Cushing’s is caused by long-term use of steroid medications. While steroid medications are helpful in managing chronic conditions and symptoms, prolonged use can be deadly.
Steroid medications can mimic cortisol, which means that continued use can lead to excessive cortisol levels. As a result, dogs experience symptoms similar to naturally occurring Cushing’s syndrome.
What Breed of Dog Is More Prone to Cushing’s Disease?
Several dog breeds are prone to developing Cushing’s, especially smaller ones. This includes dogs such as:
Boston Terriers
Boxers
While the condition can affect any dog, Cushing’s syndrome was observed in these dogs due to a genetic predisposition to the development of tumors on the glands involved.
Cushing's Disease in Dogs Symptoms
Cushing’s disease in dogs develops slowly, which makes it easy to overlook early signs. Many symptoms are also often mistaken for other conditions. Dogs with Cushing’s syndrome may show a combination of these common symptoms:
Increased Thirst and Urination. One of the first signs you will notice is when your dog has increased thirst and urination. You might see your dog suddenly emptying the water bowl or having accidents in the house.
Excessive Hunger. Dogs with Cushing’s disease often seem constantly hungry, even after eating their usual meals. This is because elevated cortisol levels interfere with normal appetites.
Lethargy and Weakness. Many dogs with Cushing’s syndrome become less active and may struggle with regular activities. You might see them having trouble with stairs and walking.
Panting and Respiratory Changes. Excess cortisol can affect breathing, leading to frequent panting, even when a dog is resting. This can be especially noticeable at night or in cooler environments where panting wouldn’t normally occur.
Hair Loss and Skin Problems. Canine Cushing’s disease often leads to thinning hair or patchy hair loss. Their skin may also become thin, fragile, or prone to infections. Unlike seasonal shedding, this hair loss does not grow back to normal.
Pot-Bellied Appearance. One of the most recognizable signs of Cushing’s syndrome in dogs is a swollen or sagging abdomen. Excess cortisol causes fat to be redistributed and muscle to be wasted. This makes the belly appear distended.
Slow Healing and Frequent Infections. Cushing’s disease weakens the immune system of dogs. As a result, dogs become more prone to skin infections, urinary tract infections, and delayed wound healing.
Behavioral Changes. Some dogs may show restlessness, anxiety, or difficulty sleeping. Increased cortisol levels can also make them more irritable or reactive to sounds that didn’t bother them before.
Are Dogs With Cushing’s Disease in Pain?
Cushing’s syndrome in dogs doesn’t directly cause pain, as the increase in cortisol levels mostly causes uncomfortable symptoms. While these can result in anxiety, lethargy, or discomfort, they don’t lead to pain.
However, secondary complications from the symptoms of Cushing’s, such as secondary infections and muscle weakness, can result in pain.
How Is Cushing’s Disease in Dogs Diagnosed?
Cushing’s syndrome in dogs develops gradually and shares symptoms with other conditions. Because of this, it’s crucial to use a combination of different tests and methods.
The first step in diagnosing this condition is a thorough checkup of the present symptoms. Our vets will look for the “five P’s,” which are essentially five key symptoms of Cushing’s. This includes polydipsia, polyuria, polyphagia, panting, and a pot-bellied appearance.
We’ll run routine bloodwork and a urinalysis to check for abnormalities related to Cushing’s disease in dogs. The signs will include elevated liver enzymes, high cholesterol, changes in white blood cell count, and diluted urine.
Diagnostic imaging also gives us clues. Ultrasounds can help assess the condition of your dog’s adrenal glands, liver, kidneys, and possible tumors. MRIs and CT scans can check for a pituitary tumor in the brain.
Standard bloodwork isn’t enough to confirm Cushing’s disease in dogs, so vets use specific hormonal tests. These will check cortisol regulation. These are the ACTH stimulation test and the low-dose dexamethasone suppression test.
For an ACTH stimulation test, a blood sample will be taken, followed by an ACTH injection. After an hour, another blood sample will be taken. This allows us to measure cortisol levels. If these are high, then these results suggest canine Cushing’s disease.
The second method also starts with a blood sample, then an injection of dexamethasone. Blood samples will be collected four and eight hours after the time of injection. In healthy dogs, cortisol levels should drop significantly. In dogs with Cushing’s disease, cortisol remains high.
How Do You Treat Cushing’s Disease in Dogs?
Once a dog has been diagnosed with Cushing’s disease, the next step is deciding on the best treatment plan. The approach will depend on whether it's pituitary-dependent, adrenal-dependent, or caused by long-term steroid use.
While Cushing’s disease cannot be completely cured, it can be managed effectively. Here’s how we do it:
Medical Management
For dogs with pituitary-dependent Cushing’s disease, medication is usually the best option. Trilostane and mitotane are two of the most commonly used medications to help manage the condition.
These medications work by reducing cortisol production in their own way. Trilostane blocks the enzyme needed to make the hormone, while mitotane selectively destroys the cells in the adrenal glands responsible for cortisol production.
Both these medications help bring hormone levels back to normal. Regular monitoring and blood tests will be done due to the strength of these medications.
Surgery
Surgery within the area of the pituitary gland is risky, so this option is more suited for dogs with adrenal-dependent Cushing’s disease. The tumor along the adrenal gland will be located and surgically removed.
In some cases, complete adrenal gland removal is a potential cure. This is called an adrenalectomy. However, this won’t be effective when the tumor has spread.
A hypophysectomy is also another possible option. This involves the removal of the pituitary gland. It’s a much more complex procedure that is sometimes used for pituitary-dependent Cushing’s disease.
Additional treatments, such as chemotherapy, will be used if needed.
Adjusting Steroid Use
If the dog’s Cushing’s syndrome is caused by long-term steroid use, the best approach is to gradually reduce the medication. However, veterinary guidance must be observed.
Stopping steroids suddenly can cause serious withdrawal symptoms, so the dose must be slowly tapered over time. In some cases, the dog’s adrenal glands may struggle to function properly after long-term steroid use. As a result, additional treatment might be required.
Here are key symptoms to watch out for:
Increased panting
Lethargy and extreme weakness
Vomiting and diarrhea
Loss of appetite
Tremors or collapse
Supportive Care and Lifestyle Management for Dogs With Cushing's Disease
Regardless of the type of Cushing’s, managing the disease requires constant monitoring and management. These will include:
Regular Vet Visits. Cushing’s disease requires lifelong monitoring to ensure your dog’s medication is working properly. Blood tests and medication adjustments will be done during your dog’s visits in order to help manage its condition.
Dietary Adjustments. A healthy diet with high-quality protein and limited fats will be used to support metabolism. Avoid foods high in sodium.
Regular Exercise. Moderate exercise will be important to maintain muscle strength without overexertion. Short walks on a consistent schedule can be a great start.
Monitoring. Watching out for complications like infections, canine diabetes, or high blood pressure will be a part of your daily routine.
What Food Is Best for Cushing's Disease in Dogs?
For dogs with Cushing’s syndrome, we recommend serving a diet low in fat and sodium. In most cases, providing bland food is a big help. This can include boiled chicken and turkey, which are nutritious foods that are easy to prepare.
Other foods that can be included in your dog’s diet include salmon, spinach, blueberries, and carrots.
How Long Can a Dog Survive With Cushing’s Disease?
While it can vary, dogs with Cushing’s can live for an average of 2 to 4 years after consistent treatment and management. However, there are also other factors that come into play when talking about a dog’s lifespan after diagnosis.
Since Cushing’s syndrome mostly affects middle-aged and senior dogs, age and health status also affect how long they live.
“A healthy dog is a happy dog, and a happy dog makes life brighter. Care for them, love them, and they’ll give you a lifetime of loyalty in return.”
- Dr. Soheyl Simaei
Final Thoughts
Cushing’s disease in dogs can be somewhat of a silent intruder. The condition can cause subtle symptoms that can be mistaken for other health conditions. Even so, there are ways to help give your dog a happy and comfortable life.
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