Cushing's Disease (Hyperadrenocorticism)
Cushing's disease is the common name for a disease called hyperadrenocorticism. It is caused by an over-productive adrenal gland that pumps too many steroids (cortisol) and other hormones into the bloodstream. It can be caused by a tumor in the adrenal gland or the pituitary gland. The pituitary form comprises 80% of all cases.
Over-production of cortisol in the adrenal gland will cause muscle atrophy, giving a thin-legged, potbellied look. It also reduces the ability to concentrate urine, making your pet drink a lot and produce a lot of dilute urine. The steroids can suppress the immune system and make your pet more susceptible to infections. These dogs often have skin or bladder infections. Other symptoms include hair loss, calcified lumps under the skin, increased appetite, panting, and high blood pressure.
Unfortunately, Cushing's disease is difficult to diagnose. There is no one test that will always identify it. We usually will diagnose it based on a blood panel and looking for an elevated Alkaline Phosphotase and dilute urine. If the bloodwork and symptoms fit, we will then do an ACTH stimulation test. If this is positive, ultrasound of the belly lets us look at the adrenals (they will be enlarged in cushings- one-sided if it is from the adrenal gland, both sides if it from the pituitary and the liver is usually enlarged. Treatment options may include surgery (removing the growth on the adrenal gland that stimulated the hormone) and/or medication (to slow down production of cortisol from the adrenal gland).
We recommend treating Cushings due to its effects on other organ systems. It may cause high blood pressure and kidney changes along with the infections and muscle weakness.
Since most cases are "pituitary dependent", medicine is the treatment of choice. We use Vetoryl (trilostane). It is a daily medication that suppresses the adrenal gland function. It must be monitored closely since if we give too much and shut down the adrenal gland it can cause death. The monitoring is done with bloodwork.
Once we have diagnosed the Cushings disease, medicine is started. After 3-4 weeks we re-run the blood panel and ACTH stimulation test and then adjust the dose of Vetoryl accordingly. If there is high blood pressure or kidney disease these will also be regulated. If dose adjustments are made, the same bloodwork is repeated in another 3-4 weeks. Once we have your dog managed we do bloodwork every 6-12 months.
Dogs regulated with their Cushings disease can live normal healthy lives.