Cushing’s Disease in Cats: Everything You Need to Know

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A cat that suffers from Cushing’s disease, or hyperadrenocorticism, has abnormally high levels of the stress hormone cortisol.

Cortisol is produced by the adrenal glands and the hormone has a vital function in the body, as it is included in the regulation of blood sugar and salts. Too much or too little cortisol can cause serious illness.

Cortisol levels are controlled by another hormone, ACTH, which is produced in the pituitary gland in the brain.

In Cushing’s disease, also called Cushing’s syndrome, cortisol production increases, usually as a result of a tumor.

If the tumor is located in the adrenal glands, it causes primary Cushing, and if it is located in the pituitary gland, so that ACTH production increases, this is called secondary Cushing. Secondary Cushing is more common than primary.

Cushing’s disease is a very rare disease in cats. It is usually middle-aged or older cats that are affected.

Another cause of Cushing is treatment with cortisol-like drugs (such as Prednisolone), so-called iatrogenic Cushing. Such drugs have a similar effect on the body as the body’s own cortisol and affect several of the body’s organs, such as the skin, joints and immune system.

They are often used because of their potent anti-inflammatory effect.

This form is also uncommon in cats, as they generally tolerate even relatively high doses of cortisone preparations.


The symptoms of Cushing’s disease vary greatly from cat to cat. The symptoms depend on the amount of cortisol present in the body and how long the levels have been too high. One or more of the following symptoms are often seen:

  • Increased thirst and urination
  • Muscle poverty
  • A large or tense abdomen
  • Skin changes in the form of thin fur, dark pigmentation and thin, delicate skin
  • Overweight
  • Lethargy


It is often difficult to diagnose Cushing’s disease in cats. Many cats that get this diagnosis also have diabetes.

The medical history together with clinical examination as well as blood and urine tests may raise suspicion of Cushing’s disease, and to make the diagnosis a special examination is required which means the cat is injected with a substance that affects the adrenal glands, in combination with blood sampling. Unfortunately, these test results are often ambiguous and further investigation to detect a tumor in the adrenal glands or pituitary gland may be necessary, often with the help of ultrasound or computed tomography or MRI examination.


Cushing’s disease can be difficult to treat in cats.

There are both surgical and medical treatments. During surgical treatment, the tumor-transformed adrenal gland is removed.

However, this method is difficult and involves the risk of serious complications. Medical treatment can also lead to the risk of serious side effects, and in these cases killing should be considered.

In the case of iatrogenic Cushing, one should try to reduce the cortisone dose, if this is possible without the cat’s underlying disease flaring up.

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