Cushing’s disease, or Hyperadrenocorticism, is due to a tumour in either the pituitary (an organ at the base of the brain) or adrenal gland (organ adjacent to kidneys). The disease causes a number of clinical and chemical abnormalities due to excess production of glucocorticoids eg. cortisone/cortisol.
Dogs with this disease tend to exhibit some or all of the following clinical features:
- Occurs between the ages of 2 & 16 years of age, but usually middle-age (6 y.o.) & older
- Slowly progressive
- Causes increased thirst & consequently increased urination
- Causes increased appetite (most dogs suffering this disease have an excellent appetite)
- Abdominal enlargement ie. “pot-bellied”
- Muscle weakness & lethargy ie. unwilling to exercise/move around as much as previously
- Hair loss, thin skin & acne
- Increased panting
- Hyperpigmentation ie. skin becomes blacker in some areas
- Liver becomes enlarged
- Calcium deposition in some areas of the skin
- Easy bruising due to poor wound healing.
- Initial general blood and urine tests gives us a presumptive diagnosis. However, because most dogs only exhibit some of the signs of the disease, and many signs can also be caused by other metabolic diseases, further tests are necessary.
- Confirmatory blood tests: between one and three further blood tests may be necessary, depending on where the tumour is.
- Ultrasound of abdomen: this can help us define the cause. Also because most of these dogs are relatively old, we can check for other problems at the same time. Sometimes the tumour has spread (metastasised) from the original site to the lungs, chest x-rays allow us to check for this.
Treatment depends on where the tumour is. Medical therapy is usually the treatment of choice. Treatment involves long-term management and dedication. Regular blood testing to ensure that the drug level within the body is correct. This will also dictate any changes in dosing.
The majority of dogs treated live for several years with relatively normal lives.