Hyperadrenocorticism (HAC), also known as Cushing’s disease, is a disorder in which excessive adrenal hormones are produced. It can be caused by abnormal pituitary gland function, tumors of the adrenal gland, or by high levels of doctor prescribed steroid use. Pituitary dependent HAC accounts for about 80% of all cases. It is a slowly progressive disease and the early signs are often unnoticed. These include increased appetite, increased drinking and urination, reduced activity, and a swollen abdomen. Extensive laboratory tests, radiographs (x-rays), or ultrasound may be needed to diagnose the condition, find its cause, and plan treatment.
How is it treated?
Some animals respond to medical management alone while others need both surgical and medical treatment. Control, rather than cure, is the outcome of treatment in most cases of HAC. Medical treatment consists of either mitotane (Lysodren) or (Lysodren) or trilostane. Patients on these medications must be closely monitored. Non-invasive adrenal tumors are best removed surgically. If adrenal hormones are suppressed too much, a condition called Addison’s disease develops and can be life threatening if untreated.
What is the prognosis for Hyperadrenocorticism (HAC)?
The average life expectancy with HAC ranges from 36 months to longer with good regulation. However, clinical signs and the development of concurrent disease like diabetes may reduce this time. If HAC is caused by a pituitary tumor, the tumor may expand and put pressure on other parts of the brain causing neurologic signs and ultimately death. Infections of the skin, urinary tract, and liver are common due to the high levels of circulating steroids that suppress the immune system. Many dogs ultimately die or are euthanized due to these complications. A personalized treatment plan is important to slow the progression of HAC. Talk to your veterinarian regarding the best treatment protocol for your pet.
