Cushing's Disease is the common name for Hyperadrenocorticism - a condition in which the adrenal glands (small glands that sit on top of the kidneys) overproduce cortisol in the dog's body. Excess cortisol causes a number of symptoms and affects almost every body system from the kidneys, to the immune system, the skin, and the liver.
There are three main forms of Cushing's Disease, correlating purely to where the cause of the disease sits anatomically:
- Pituitary Dependent Cushing's. This is the most common form, seen in about 80-90% of dogs with Cushing's. The pituitary gland is a pea sized gland at the base of the brain, and one of its functions is to send signals to the adrenal glands. If the pituitary gland is over active, the otherwise normal adrenal glands will respond to this overstimulation. Usually, a tumour in the pituitary gland causes its hyperactivity - but the tumour itself is oftentimes benign.
- Adrenal Dependent Cushing's. This type of Cushing's is caused by overactive adrenal glands. In most cases, the overactivity is caused by a tumour in an adrenal gland, which causes it to expand and produce excess cortisol. Around 15% of dogs with Cushing's have this type.
- Iatrogenic Cushing's. Iatrogenic typically means 'caused by medication'. This type of Cushing's occurs after a dog has been treated with corticosteroids for a long time.
Did you know? Cortisol is normally used by the body to respond to stress, keep bodyweight in check, fight infections, and maintain blood sugar levels. However, like many hormones, too much or too little Cortisol can cause problems.
Dog breeds that are prone to Cushing's Disease
Small breed dogs are particularly prone to Cushing's Disease, however some large breed dogs are affected more than others too. Certain breeds that are prone to developing Cushing's include:
