Hyperadrenocorticism (Cushing’s disease) is a common disease in middle-aged to older dogs. It’s most commonly caused by a benign (non-cancerous) pituitary tumor that directs the adrenal glands to produce excess cortisol (stress hormone). This form of Cushing’s is called pituitary-dependent hyperadrenocorticism. Less commonly, hyperadrenocorticism is caused by an adrenal tumor that produces excess cortisol, termed adrenal-dependent hyperadrenocorticism.
Cortisol helps to regulate vital functions of numerous body systems. Cortisol plays a critical role in the body’s response to stress or illness. Excess cortisol, as seen with Cushing’s disease, can cause numerous clinical signs, including increased thirst and urination, increased appetite, potbellied appearance, hair loss, changes to the skin, and increased panting. More severe complications of hyperadrenocorticism may include recurrent infections (skin, urinary, other), high blood pressure, the formation of blood clots, and insulin resistance.
Hyperadrenocorticism may be suspected based on the pet’s age, physical exam findings, and clinical signs noted at home, but definitive diagnosis of Cushing’s requires specific blood tests. There are several tests for Cushing’s that are used not only to determine whether your pet has Cushing’s, but also whether it’s more likely pituitary-dependent or adrenal-dependent. In addition to these tests, full blood work and urine testing are frequently advised, as Cushing’s is commonly associated with elevated cholesterol and ALP (specific liver enzyme), as well as urinary tract infections.
There are several treatment options for Cushing’s depending on the form present. In addition to medications to treat Cushing’s directly, other medications may be advised to treat high blood pressure, treat concurrent infections, and/or reduce the risk of blood clots.