Cushing’s disease (orhyperadrenocorticism) can affect any dog, however it usually affects middle aged dogs. It is when the body produces too much of the hormone cortisol and it can be managed with medication.
What is Cushing’s disease?
The adrenal gland is located next to the kidney, and it produces cortisol. The pituitary gland (located at the base of the brain) sends messages to the adrenal gland to produce cortisol. Dogs can get a growth on either the adrenal gland or pituitary glands and this leads them to produce excess hormones. At normal levels, cortisol provides many important functions such as responding to stress, but if the levels of this hormones are too high, it can be troublesome.
When a dog is stressed, the cortisol tells the body to work harder to fight off the cause of the stress. The reaction of this is increased metabolism and a release of energy in the form of sugar and fat, as well as holding onto water. The body will react by releasing enough energy to fight the stressor whenever cortisol is produced. When this goes on for a prolonged period, the dog can become prone to health issues e.g. infections.
Types of Cushing’s disease
- Adrenal – this is less common, with 15-20% dogs diagnosed will have this type.
- Pituitary – much more common with 80-90% dogs affected.
- Iatrogenic Cushing’s syndrome – occurs when a dog has taken steroids for a long time.
Symptoms of Cushing’s disease
- Increased urination
- Increased drinking
- Hair loss
- Abdominal swelling
- Muscle weakness
- Loss of appetite
How is Cushing’s disease diagnosed?
Your vet will need to do a series of tests to diagnose Cushing’s disease. Blood and urine samples will be taken to be analysed. Hormone screening is then required, such as;
- An ACTH stimulation test – Blood samples are taken before the test is carried out and then your dog is given ACTH which should prompt the adrenal glands to make cortisol and then another blood sample is taken to measure this response.
- Low dose dexamethasone suppression (LDDS) test – like the previous test, blood samples are taken before and after dexamethasone (a man-made version of cortisol) is administered.
How is Cushing’s disease treated?
The treatment depends on where a tumour is located.
- Adrenal gland – as long as a tumour has not spread, it can be operated on and removed. Your vet may give medication first to try and shrink it before operating. This type of surgery is usually done at a specialist vet.
- Pituitary gland – this cannot be operated on, and so your dog will require medication for the rest of their life. Your dog will need regular check-ups from your vet and will need to have the ACTH stimulation test every few months to ensure they are receiving the correct dosage of the drug. It is worth remembering that the dose your dog will require is likely to change over time, which is why it is so important your vet sees them regularly.
Will my dog still have quality of life with Cushing’s?
It is important to understand that Cushing’s disease doesn’t mean a death sentence and your dog can still be happy and enjoy life. You must remember to keep an eye out for any subtle changes in their behaviour, such as drinking more and lethargy as these could mean your dog’s dose needs adjusting.