Blood samples are taken before testing, and at 4 and 8 hours after the injection of a steroid called dexamethsone. In dogs with Cushing's, the serum cortisol levels do not go down. Another version of this test uses a higher dose of dexamethasone to help differentiate adrenal tumor produced disease from that of the pituitary gland. Dogs with adrenal tumors do not suppress their level of cortisol while in pituitary tumor patients it usually will drop. These animals usually have very large tumors.
Treatment usually consists of destroying the part of the adrenal cortex that produces steroids.
An initial dose period is usually followed by a maintenance dose period. It may be as seldom as once a week. The animal will have to be monitored lifelong. A few of the dogs may develop a potentially dangerous condition called hypoadrenalcorticism or Addison's disease. This is the opposite extreme from Cushing's.