Cushing’s Syndrome

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Information on Cushing’s syndrome in dogs.

What is it?

Dogs with Cushing’s syndrome produce excessive amounts of steroid, or cortisol.

• Cortisol is a hormone that helps to regulate the body’s metabolism and it is produced by the adrenal glands.
• A hormone called ACTH produced by the pituitary gland in the brain, controls and stimulates the production and release of cortisol from the adrenal glands.
• In Cushing’s syndrome, there is a chronic overproduction of cortisol which eventually has a harmful effect on the function of many organs and the body’s metabolism.

Causes

• ACTH-producing tumours form in the pituitary gland, this in turn stimulates an over-production of cortisol.
• Cortisol-producing tumours form within the adrenal gland, directly producing too much cortisol.
• Sometimes caused by us when the pet receives too much cortisol, or steroids, in tablet or injection form. This is sometimes the price of controlling some other serious diseases.

Signs

• Hair loss or skin disease
• Increased thirst + appetite
• Lethargy
• Excessive panting
• Frequent urination
• Pot-belly

Diagnosis

• Urine sample; to check the concentration of the urine and rule out other problems.
• Blood test; a general health profile to look at organ function and to rule out other diseases.
• ACTH stimulation test; as the concentration of cortisol in the blood changes throughout the day a diagnosis cannot be confirmed by just one measurement of cortisol. Blood is taken to measure cortisol before and after the dog is given a synthetic version of the hormone, ACTH. This test assesses how well the dog’s adrenal glands control the production of cortisol.
• Abdominal ultrasound examination; performed to evaluate all the organs and to look at the size and shape of the adrenal glands.

Treatment

• Non surgical treatment is the most often used treatment for most cases of Cushing's disease.
• About 80% of the cases of Cushing's disease in the dog are of the pituitary type, and since both the adrenal and the pituitary type will respond effectively to some of the oral treatments, many vets do not perform the diagnostics necessary to distinguish between the two different forms.
• There are currently several different oral medications being used to treat canine Cushing’s syndrome. These work by blocking the production of cortisol by the adrenal glands.
• Follow up blood tests are performed after the pet has been on medication for a while to monitor its’ effectiveness.
• Specialist surgery can be done to remove adrenal tumours. Pituitary gland tumours are not usually removed.

Prognosis

Cushing’s syndrome cannot be cured but it can be successfully managed and controlled with medication.