Mitotane (Lysodren) and trilostane (Vetoryl) are oral medications that selectively destroy part of the adrenal cortex so that although the pituitary gland tumor continues to release ACTH, cortisol levels remain normal. We treat most dogs with pituitary-based CD with medication. Though pituitary tumors are routinely removed in people, this surgical technique is still in its infancy in dogs. This type of tumor is only millimeters in size and is often benign, but it’s problematic because it manufactures and releases uncontrolled quantities of ACTH, which, as explained above, stimulates the adrenal cortex to release excessive amounts of cortisol. More than 90 percent of dogs with CD have a pituitary-gland tumor.
The location of the tumor dictates which treatment to use. Ultrasound examinations also allow the veterinarian to determine whether or not a tumor is present, and if it’s located in the pituitary gland or the adrenal glands. If the cortisol level fails to drop, it suggests there is a tumor not responding to the medication. In a healthy dog, the cortisol level goes down over the following few hours because the steroid suppresses adrenal production. The veterinarian may also use a second method, the dexamethasone suppression test, in which the dog receives an injection of the steroid dexamethasone. If it starts high and climbs even higher, a diagnosis of CD is confirmed. If the dog’s cortisol level goes up a little, his adrenal response is normal. For this test, a blood sample is drawn from the patient, then he is given an injection of ACTH, and a second blood test is taken a few hours later. Dilute urine and an elevation of the liver enzyme alkaline phosphatase in the blood indicate that testing for CD may be necessary.Ĭushing’s disease can be verified with an adrenocorticotropic hormone (ACTH) stimulation test. When a veterinarian suspects this disease, blood, and urine tests are needed to make the diagnosis. Almost all patients are older than eight years when CD develops.ĭiagnosing CD is not easy and can be quite expensive. The Poodle, Dachshund, Boston Terrier, Boxer, and Beagle are some breeds to watch. This form resolves once the steroids are stopped.Ĭertain breeds are at a higher risk of developing CD. Affected dogs develop symptoms that are identical to those of the tumor-based disease. Chronic application of steroid-containing ear drops can also cause the condition because the medication is absorbed through the skin. Causes of Cushing’s DiseaseĬushing’s disease is a naturally occurring syndrome, but it can also be caused by administering excessive amounts of prednisone or dexamethasone for prolonged periods.
Obesity and lack of energy are also symptoms.īecause it takes time - at least one year - for these symptoms to develop, and because the symptoms are often mistaken for common signs of aging, many dogs have the advanced form of CD before the owner even recognizes a problem exists. Owners might notice a thinning of the skin, lesions on the skin, and hair loss on the flanks, neck, and perineum. As the disease progresses, dogs lose muscle and become weak. The disease causes extreme thirst, so a dog with CD tends to drink tremendous amounts of water and urinate frequently. Often owners report that their first clue that something might have been wrong was their dog wanting to go out at night to urinate. In a pet with CD, a tumor in the pituitary gland or, less commonly, in one of the adrenal glands, causes the cortex to release an excess amount of cortisol. The pituitary gland, a tiny gland found at the base of the brain, releases adrenocorticotrophic hormone (ACTH), which in turn tells the adrenal glands to release cortisol, also called glucocorticoids.
These two peanut-sized glands, situated in front of the kidneys, produce hormones to help the body perform essential functions. Cortisol is controlled by the adrenal cortex, located on the outer layer of adrenal glands. You may have heard of the stress hormone cortisol and the associated “fight or flight” response. Treatment is expensive and ongoing, and it requires consistent monitoring. This condition, usually caused by a tumor in the pituitary gland, is far more common than we realize, but because of the complex diagnostic testing required, it’s underdiagnosed. One cause your veterinarian may test for is Cushing’s disease (CD), also known as hyperadrenocorticism. If your older dog is drinking and urinating more than usual, it could be caused by a variety of reasons.
0 kommentar(er)
