Cushing's disease in dogs

Written by Audrey Pavia Reviewed by Kristin Westafer, DVM

Overview

Cushing's disease in dogs is a condition involving too much production of the hormone cortisol by the adrenal glands. This is either caused by a mass involving the pituitary gland in the brain or from a mass in an adrenal gland. Too much cortisol in the body can result in a host of symptoms. Cushing's, which is also called hyperadrenocorticism, affects different organs of the body and can even be fatal if it results in a blood clot to important organs, high blood pressure, and kidney failure.

Cushing's disease is difficult to diagnose, and is most often come to as a cause for various symptoms based on ruling out other possible diseases. In some cases, certain tests such as the urine cortisol/creatine ratio test can rule out Cushing's disease. The ACTH stimulation and low-dose dexamethasone suppression test can also help veterinarians determine whether Cushing's is present. The high-dose dexamethasone suppression test helps your veterinarian determine if a malfunctioning adrenal gland or pituitary gland is the source of the problem.

In most dogs, Cushing's is caused by a benign tumor on the pituitary gland, which affects the adrenal glands. In some cases, a tumor is located directly on the adrenal glands, resulting in Cushing's disease.

Cushing's is the most common disease of the endocrine system for older dogs. Some breeds seem predisposed to Cushing's, including Beagles, Boston Terriers, Boxers, Dachshunds, German Shepherds, Golden Retrievers, Labrador Retrievers, Poodles and all breeds of terriers.

Symptoms

Hair loss
Pot-bellied appearance
Increased urination
Increased water consumption
Increased appetite
Prone to bruising
Apparent weight gain
Skin problems
Increased panting

Prevention

Unfortunately, Cushing's disease cannot be prevented. The benign tumors that cause the disease have an unknown origin.

Treatment

A number of different treatments are available for Cushing's disease, depending on the cause of the illness.

Cushing's caused by adrenal tumors can be treated surgically. The tumor and the affected adrenal gland are both removed. Elderly dogs that are not in good general health may not be candidates for this surgery, however. Surgery can be very risky, especially if the tumor is extremely large, because of the important blood vessels that are in the area of the adrenal glands.

Non-surgical options for dogs with Cushing's caused by an adrenal tumor include treatment with a drug called ketoconazole, which suppresses hormone production and reduces symptoms of the disease. Ketoconzaole is very expensive and can cause problems with the liver. It is talso ypically not very effective at controlling Cushing's disease.

For dogs with Cushing's caused by a pituitary tumor, a variety of drug treatments are available. Some veterinarians also choose radiation as a treatment to help shrink the tumor. Trilostane and mitotaine are drugs that are commonly used to treat Cushing's disease. Pay close attention to the dosing instructions and pay particular attention to your dog's appetite and behavior when on these medications. Report any concerns and questions to your veterinarian.

The cost of treatment for Cushing's can vary widely depending on the cause of the disease and the best course of treatment based on the dog's overall health.

After treatment

Dogs treated for Cushing's often respond successfully to surgery, radiation, or medication. Their symptoms tend to subside within 4 to 6 months. In most cases, however, the disease cannot be cured. Instead, owners must manage Cushing's with medication and good overall care.