The two small adrenal glands are located just above each kidney. The cortex (outer layer) of the adrenal glands produce and release corticosteroids.
The production and release of corticosteroids by the adrenal glands is controlled by the pituitary gland (a small gland which is located at the base of the brain), through the production of a hormone called adrenocorticotropic hormone (ACTH).
There are two types of corticosteroids – mineralocorticoids and glucocorticoids.
These are very important hormones – mineralocorticoids regulate electrolyte concentrations, and glucocorticoids reduce inflammation and suppress the immune system.
The level of corticosteroid concentration in the body depends on the need at the time.
Normally, the hormones are released by the body into the bloodstream when the dog is under some form of physical or mental stress.
For example, when a dog is not well or is put under a stressful situation, the production and release of corticosteroids will be increased.
Once this particular stressful situation is over, the hormone concentration will return to normal.
Cushing’s disease in dogs (hyperadrenocorticism) is a condition caused by a long-term (over weeks or months) exposure to high levels of corticosteroids.
The high levels of corticosteroids may be the result of over-production by the body itself, or they may be given to the dog as medications (corticosteroids are often prescribed to treat inflammation).
Cushing’s disease is the opposite of canine Addison’s disease, in which the adrenal glands produce insufficient amount of corticosteroids.
Possible Causes of Cushings Disease in Dogs
Cushing’s disease can be “spontaneous” (meaning: the body produces high levels of corticosteroids), or “iatrogenic” (meaning: the high levels of corticosteroids are caused by long-term drug therapy that contains corticosteroids).
Spontaneous Cushings disease in dogs can be caused by one of the following:
- Tumors of Pituitary Gland: This is the most common cause of spontaneous Cushing’s disease. Up to around 85% of all cases of spontaneous Cushing’s disease in dogs are caused by pituitary gland tumors. The tumor cells cause the pituitary gland to over produce ACTH. This results in the over-production of corticosteroids by the adrenal glands.
- Tumors of Adrenal Glands: The remaining cases of spontaneous Cushing’s disease are caused by a tumor in either one, or in rare cases, both of the adrenal glands.
Spontaneous Cushings disease usually occurs in middle-aged and older dogs. Breed-wise, Poodles, Dachshunds, Boston Terriers, and Boxers are more prone to the disease.
Symptoms of Cushings Disease in Dogs
One typical symptom of canine Cushings disease is hair loss in a symmetric pattern, with darkening of the underlying skin. The hair that remains will become dry and dull.
In addition, a dog with Cushing’s disease will also show the following signs and symptoms:
- A sagging, distended pot belly
- Weak muscle tone
- Small blackheads on the abdomen
- Weakness and lethargy
- Excessive thirst
- Frequent urination
- Appetite gain and weight gain
Cushing’s disease will in turn cause other health problems, such as:
- Congestive heart failure
- Diabetes mellitus
- Infections (e.g. ear infections, urinary tract infections, skin infections)
Treatment of Cushings Disease in Dogs
Spontaneous Cushing’s disease in dogs caused by tumors of the adrenal glands can be treated by the surgical removal of the tumors.
Drug therapies are also available.
The conventional medication is mitotane (Lysodren) which acts on the adrenal cortex to suppress corticosteroid production.
This therapy requires careful veterinary monitoring and, with medication, the life span is about two years.
Cushings disease caused by pituitary tumors is more complicated.
Surgical removal of pituitary tumors can be dangerous due to its location. Although radiation therapy is available, it is costly.
A drug called Anipryl (deprenyl) is available for use on Cushings disease caused by pituitary problems.
Although it appears that the drug is rather effective in improving some of the symptoms caused by Cushing’s disease, it can cause possible adverse side effects, such as vomiting, diarrhea, lethargy, loss of appetite, and seizure.
Iatrogenic Cushing’s disease can usually be cured by discontinuing or reducing the drug that is causing the disease.
A Natural Product for Cushings Disease
Natural remedies cannot cure Cushings disease in dogs. However, some herbal remedies may be able to strengthen the over-taxed system organs and reduce the severity of symptoms caused by the disease.
One such natural remedy is:
Be sure to discuss the use of this natural product in conjunction with other conventional therapies with your veterinarian.