Adrenal Cushing's Disease in Dogs
You notice your female dog drinks a lot of water and urinates more than normal, and upon examination and a blood test, your veterinarian diagnoses your beloved pooch with Cushing's disease. Because Cushing's can be a lifelong disorder and can have dire consequences for your pet, it is important that you educate yourself in order to provide the best treatment possible for the comfort and longevity of your dog.
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Types
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The veterinarians at the Pet Education website explain that there are two different types of Cushing's disease---pituitary-dependent hyperadrenocorticism (PDH) and adrenal-based hyperadrenocorticism. PDH occurs when the excessive secretion of ACTH hormone, a normal product of the pituitary gland, causes the adrenal glands to over-produce glucocorticoids (namely cortisol). The adrenal-based form of the disease results from a tumor on the base of the glands that causes the overproduction of cortisol. According to Pet Education, "Adrenal tumors are responsible for around 20 percent of the cases of Cushing's disease."
Significance
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The increase in cortisol that is the cause of your dog's Cushing's disease causes liver enlargement and liver enzymes in the blood to be elevated. Your animal can also show an increase in blood sugar and cholesterol, very dilute urine and an enlargement of the adrenal glands. Excess cortisol suppresses your dog's immune system, making her more susceptible to bladder and skin infections, according to veterinarians at Washington State University's College of Veterinary Medicine.
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Symptoms
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In "Common Diseases of Companion Animals," Dr. Alleice Summers describes a dog with Cushing's as being typically female (60 to 65 percent) and over 6years of age. They exhibit excessive panting as well as drink and eat more than usual. They may urinate more than normal and become obese with exaggerated abdominal enlargement. Cushing's dogs show signs of muscle weakness and lethargy, extreme skin itching, hair loss and skin infections. If they are still intact, females do not come into heat and males display small, soft testicles.
Treatment
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Veterinary treatment may involve surgery if an adrenal tumor is indicated; however, because the surgery is "quite specialized and dangerous", many veterinarians opt to have a specialist perform the surgery or treat with medications, says Dr. Ron Hines in "Treating Cushing's Disease in Your Dog."
Veterinarians typically treat Cushing's dogs with lysodren, a DDT-like compound that destroys the layer of the adrenal glands that produces the cortisol. Side effects include lack of appetite, nausea, diarrhea and vomiting, and animals on this drug need consistent veterinary monitoring. Vets may also use anipryl and ketoconazole for treatment. Although these medications have fewer side effects than lysodren, they are also less effective, says Dr. Hines.
In December 2008, the U.S. Food and Drug Administration (FDA) approved trilostane (trade name Vetoryl) for the treatment of both PDH and adrenal-based canine Cushing's. Trilostane works by discontinuing production of cortisol in the affected animal's adrenal glands. Studies show common side effects consist of lethargy, diarrhea, weight loss and vomiting; the FDA does not recommend this drug in dogs suffering from kidney or liver disease, pregnant animals or dogs on certain heart medications.
Warning
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Without treatment, your Cushing's dog is likely to develop high blood pressure, diabetes, diseases of the nervous system and heart disease---all potentially fatal disorders, say the doctors at the Vet Info website.
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References
- Pet Education: Cushing's Disease (Hyperadrenocorticism) in Dogs
- Washington State University College of Veterinary Medicine: Cushing's Disease
- "Common Diseases of Companion Animals"; Alleice Summers, DVM; 2002
- 2nd Chance Sanctuary: Treating Cushing's Disease in Your Dog
- U. S. Food and Drug Administration: Treating Cushing's Disease in Dogs
Resources
- Photo Credit dogs portrait image by Tomo Jesenicnik from Fotolia.com
