What is Cushing's disease in dogs?

Cushing's disease in dogs can lead to a number of serious symptoms and complications that can threaten your pup's longevity. In today's post our Greensboro vets share more about the causes of Cushing's disease in dogs, as well as possible complications and available treatments.

Causes of Cushing's Disease in Dogs

Cortisol is a natural steroid that helps to regulate proper body weight, tissue structure, skin condition, and more.  A tumor in your dog's pituitary gland can lead to an excessive concentration of cortisone in your pup's body resulting in pituitary-dependent Cushing’s disease. Officially called hyperadrenocorticism, Cushing's disease is a clinical condition that can put your pooch at risk of several serious conditions and illnesses, from kidney damage to diabetes.

Approximately 80-85% of cases of Cushing's disease in dogs is pituitary-dependent, however adrenal-dependent forms of the disease can also strike dogs. Adrenal-dependent Cushing's disease occurs when a tumor on one or both of the adrenal glands leads to an excess of cortisol. This form of the disease accounts for about 15-20% of Cushing's cases in dogs.

Symptoms of Cushing's Disease in Dogs & Possible Complications

In dogs, the most common symptoms of Cushing’s disease include:

If your dog is suffering from Cushing's disease you may notice one or more of the above symptoms. Many signs of Cushing's disease are vague but it's important to take your pup to see your vet for an examination if you notice that they are displaying any of the common symptoms of Cushing's.

Pets with Cushing’s disease face an increased risk of developing a host of serious conditions including kidney damage, high blood pressure, blood clots, and diabetes if the condition is left untreated.

Diagnosing Cushing's Disease in Dogs

Diagnostic testing is required to diagnose Cushing's disease since there are a number of conditions that share similar symptoms. An adrenocorticotropic hormone (ACTH) stimulation test is a blood test frequently used when diagnosing Cushing's disease in dogs. Other tests that your vet may recommend include urinalysis, urine culture, various adrenal function tests, a full chemistry panel, and a complete blood panel.

Ultrasound imaging can be helpful in ruling out other conditions that could be causing your dog’s symptoms, although MRI is typically a more effective tool in the diagnosis of Cushing's disease. That said the use of MRI can be costly.

Our Board-Certified Veterinary Internal Medicine Specialists at At Carolina Veterinary Specialists in Greensboro are trained to diagnose and treat a wide range of internal diseases and conditions. Our in-house lab and diagnostic tools allow us to quickly identify and manage conditions such as Cushing's in pets. 

Treatment for Dogs with Cushing's Disease

Treating the more common pituitary-dependent Cushing's typically relies on two main medications; the insecticide DDT (Lysodren^® and Mitotane) which works to destroy the cells that produce cortisone, and trilostane (Modrenal, Vetoryl, and others) which may also help to decrease cortisone production. In some cases, Selegiline hydrochloride (Anipryl®), and ketoconazole (Nizoral®) may be used to treat canine Cushing’s disease, 

The first line of defense for treating adrenal-dependant Cushing's in dogs is surgery to remove the tumor. If the surgery is uncomplicated and the tumor hasn't spread and isn't malignant, there is a chance that your pup could return to normal health. That said, treating this form of Cushing's can be complicated. When surgery isn't an option there are a number of medications that may be used to treat your pup's adrenal-dependant Cushing's including those mentioned above and the chemotherapy drug Lysodren.

Regardless of which medication your vet prescribes for your dog, there is a good chance that your pup will need to remain on it long-term, and require periodic adjustments to the dosage. 

The only cure for Cushing's disease in dogs is surgery to remove the tumor from the adrenal gland, provided that it hasn't spread and is easy to reach, which is rare. If surgery is not an option for your dog, with diligent observation and long-term management, the symptoms of your pup's Cushing’s can be minimized.

When medications for Cushing's are administered in just the right dosage, they can prove very effective in treating the condition. Your pup will need to visit the vet regularly for blood tests including an ACTH stimulation test (to test cortisol levels) as well as tests to check the levels of medication in your dog's blood. Too much or too little of these medications can lead to complications.

With regular blood test monitoring adverse reactions are rare, but when they do occur they can include:

• Depression, lethargy or weakness
• Stomach upset and GI symptoms such as diarrhea or vomiting
• Picky eating or decreased appetite

If you notice that your dog has any of these symptoms, discontinue the medication and call your veterinarian right away.

While medication costs and the need for frequent blood monitoring can make Cushing’s disease expensive to manage, diligent follow-up care and monitoring for adrenal function can lead to a good prognosis. Pets who do not receive adequate monitoring and follow-up often experience relapses, severe symptoms of the illness, or death as a result of complications.

Prognosis for Dogs with Cushing's Disease

Many concerned pet parents ask 'Is Cushing's disease fatal?' - Although according to the American Kennel Club the average survival time for a dog with Cushing's is about two years, with only 10 percent living beyond the four-year mark, it's  important to remember that most cases of Cushing's disease are diagnosed in geriatric dogs. Meaning that the cause of death may not be related to Cushing's disease. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.