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Hyperadrenocorticism (Cushing’s Disease) Hyperadrenocorticism (Cushing’s Disease) is a complex endocrine disorder in which multiple organ systems are affected by elevated levels of circulating cortisol. Spontaneous or naturally occurring Cushing’s disease is caused by excessive production of cortisol by the patient’s adrenal glands. In 85 to 90% of patients the excess cortisol production is due to excessive production of adrenocorticotropic hormone (ACTH) by the pituitary gland at the base of the brain. The excess ACTH causes the adrenal glands to produce excess cortisol. The remaining 10 to 15% of patients have cortisol-secreting adrenal tumors. Approximately one half of the adrenal tumors are malignant. Iatrogenic Cushing’s disease is caused by excessive administration of glucocorticoid (steroid) medications. Cushing’s disease is common in dogs and rare in cats and generally affects middle-aged to older animals. DIAGNOSISThe diagnosis of Cushing’s disease is based on history, physical examination, and laboratory findings. Dogs with Cushing’s disease typically show excessive drinking, urination, and panting, increased appetite, hair loss (usually symmetrical), lethargy, blackheads (comedomes), muscle atrophy, skin hyperpigmentation, have a pot-bellied appearance, and may be affected by recurring infections (ears, skin, urinary tract, etc.) or abnormal calcification of the skin (calcinosis cutis). Laboratory tests used to diagnosis Cushing’s disease include a complete blood cell count, chemistry profile, urinalysis +/- urine culture and sensitivity, and an ACTH stimulation test. To distinguish between pituitary dependent Cushing’s disease and adrenal tumors we may recommend a high-dose dexamethasone suppression test. Occasionally radiographs or ultrasound may be necessary to look for adrenal tumors. TREATMENTThe goal of therapy for Cushing’s disease is to decrease the excessive water consumption, excessive urination, and increased appetite, and to improve the pet’s skin conditions and infections. Pets with Cushing’s disease can be treated with two different oral medications: Lysodren (mitotane) or Anipryl (selegiline hydrochloride or l-deprenyl). Results may be seen as soon as one week after initiation of therapy or as long as 6-8 weeks after therapy begins. Both medications need to be given for the life of the pet. If medical treatment is discontinued, clinical signs of Cushing’s disease will recur. Surgery is an option for animals with adrenal tumors. Lysodren reduces the tissue in the adrenal glands which is overproducing the cortisol. Lysodren therapy is more likely to be effective than Anipryl, but carries with it greater risks of side effects. Potential side effects of Lysodren therapy include: vomiting, diarrhea, shaking, weakness, collapse, and decreased appetite. If you notice any of these symptoms please give prednisone as directed by the label and call the clinic at 651-777-1393 as soon as possible. Do not give any more Lysodren until you have called the clinic. Lysodren therapy costs from $5-15 per week. Anipryl decreases production of ACTH in the brain. Anipryl therapy is less likely to be effective than Lysodren, but carries with it fewer risks of side effects. Potential side effects of Anipryl therapy include: vomiting, diarrhea, restlessness, lethargy, increased salivation, and decreased appetite. Anipryl therapy costs approximately $30 per week. We will need to recheck the pet one to two weeks following initiation of medical treatment. At that time we will weigh the pet, assess how they have done on the medication, look for changes in clinical signs, and discuss possible blood work. Please fast your pet for 12 hours prior to your appointment. Please call our offices to schedule an appointment. Additional recheck appointments will be necessary to continue to monitor the pet’s response to therapy. PROGNOSISDepending on which body systems are affected, response to treatment is generally seen within several days to months. Left untreated Cushing’s disease is a progressive disease with a poor prognosis. Most patients treated for Cushing’s disease generally have a good prognosis. The average survival time for patients treated with Lysodren is two years with at least 10% surviving for four years. Patients with benign adrenal tumors have a good to excellent prognosis. Pets with small malignant adrenal tumors that have not spread to other parts of the body have a fair to good prognosis. Patients with large malignant adrenal tumors that have spread to other parts of the body have a poor to fair prognosis. If you ever have questions regarding any of the above information, please do not hesitate to contact us. Visit us online at www.WhiteBearAnimalHospital.com. WHITE BEAR ANIMAL HOSPITAL OTTER LAKE ANIMAL CARE CENTER 1909 East County Road
E 6848 Otter Lake Road
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