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Hyperadrenocorticism

Other Names: Cushing's Disease

Hyperadrenocorticism (Cushing's Disease): An Overview

Commonly known as Cushing's disease, hyperadrenocorticism is a disease which results from a chronic surplus of cortisol. Cortisol is a glucocorticoid steroid which is secreted from the adrenal glands. This secretion is regulated by the ACTH-hormone secreted by the pituitary gland.

Causes of Hyperadrenocorticism

There are two mechanisms which can cause Cushing's disease. The most common mechanism is called pituitary dependent hyperadrenocorticism (PDH) and accounts for between 85-90% of all cases. PDH occurs when a tumor in the ACTH-hormone containing cells of the pituitary gland causes high amounts of the ACTH-hormone to be produced. This in turn causes excess amounts of glucocorticoids to be secreted. The second mechanism, but far less common, is functional adrenal tumors. In functional adrenal tumors there is a tumor on the adrenal gland which causes an excess of glucocorticoid steroids to be released. Along with those two mechanisms the symptoms of Cushing's disease can be induced by iatrogenic means. In the iatrogenic means steroids, such as prednisone, given to the dogs by a physician over long periods of time and in high doses can cause the dog to show these signs. This is the easiest to treat due to the fact that by stopping the medication the dog's body can return to normal over time.

Although any breed can be affected by Cushing's disease there are some breeds which seem to be at a greater risk for developing it than others. These breeds include Miniature Poodles, Dachshunds, Boxers, Boston Terriers, and Beagles.

Symptoms of Hyperadrenocorticism

Cushing's disease is fairly common in dogs but not in other species. The most common age group of dogs to acquire Cushing's is middle age to older dogs; ages 7 and up. There can be many symptoms seen with Cushing's due to the fact that the glucocorticoid steroids affect many aspects of the dog's body. Some of the main ones include: hair loss on the trunk of the body, increased food and water consumption, lethargy, recurrent bladder infections, and a "pot belly" look. The disease progresses very slowly causing symptoms to go unnoticed in some cases due to the fact that owners do not notices these slight changes in their pet's habits. The main symptom that owners bring their pet in for is hair loss.

Diagnosing Hyperadrenocorticism

Cushing's disease is diagnosed using screening tests. There are multiple tests which can be used. Three of the more common ones are a urine cortisol test, low dose dexamethasone suppression test, and an ACTH stimulation test. In all the tests abnormalities are looked for which indicate high levels of cortisol. As there are many different reasons for abnormal test results multiple tests are normally done to get a definitive diagnosis along with determining the form of the disease present.

Treating Hyperadrenocorticism

There are different treatments for Cushing's disease. One type of treatment is to remove the tumors. This procedure however is risky and there can be many complications which come up after surgery. The drug Lysodren can be used to reduce the amount of steroids being produced. The drawbacks to this are that a veterinary must monitor the administration of the medicine, usually once a week, and is almost always required for the rest of the dog's life. Supportive methods are also used such as feeding a special diet per the dog's new nutritional requirements and treating secondary problems as they occur.

The AKC Canine Health Foundation and Hyperadrenocorticism

The AKC Canine Health Foundation has been a part of research which focused on the cause of Cushing's disease. With a better understanding of what causes Cushing's disease it will hopefully be possible to find better treatments and possibly prevent the disease from occurring. With your support the AKC Canine Health Foundation will be able to continue to fund projects which benefit all dogs.

Related Grants

00687-A: Fluorescence-Activated Cell Sorting of Canine Pituitary Corticotroph Cells for Subsequent Microarray Analysis

Help Future Generations of Dogs

Participate in canine health research by providing samples or by enrolling in a clinical trial. Samples are needed from healthy dogs and dogs affected by specific diseases.