Cushing’s disease (hyperadrenocorticism) is a thyroid disorder that occurs when a pet’s adrenal glands overproduce the hormone cortisol. The disease tends to occur in middle-aged and senior pets, and is more common in dogs than cats.
Cortisol is vital for your pet’s health. It performs important functions in the body including suppressing the immune system and helping an animal respond to stress. However, too much cortisol can cause serious and potentially life-threatening health problems.
Causes of Cushing’s Disease
The most common cause of Cushing’s disease is a tumor of the pituitary gland, a small gland located at the base of the brain that produces a number of important hormones. Tumors of the pituitary gland are usually benign (noncancerous), but in rare cases they may be malignant (cancerous).
A less common cause of Cushing’s disease is a benign or malignant tumor of the adrenal gland. Both pituitary gland and adrenal gland tumors stimulate the overproduction of cortisol in your pet’s body.
Cushing’s disease may also be iatrogenic. This means that the excess of cortisol in your pet’s body has occurred as the result of long-term or high-dose administration of corticosteroids. These medications are routinely prescribed to treat health problems including allergies and inflammatory diseases.
Symptoms of Cushing’s Disease
Please visit your veterinarian immediately if your pet displays any of the following potential signs of Cushing’s disease.
- Increased thirst and urination
- Increased appetite
- Weight gain or obesity
- Pot-bellied abdomen
- Thin skin
- Lethargy
- Excessive panting
- Hair loss
- Weakness
Diagnosis of Cushing’s Disease
Your veterinarian will look at your pet’s medical history and perform a physical examination to check for clinical signs of Cushing’s disease. Preliminary tests such as blood work and urinalysis are often used to evaluate your pet’s overall condition.
Further tests will then be performed to reach a conclusive diagnosis. These may include a low-dose dexamethasone suppression test (LDDST) to assess blood cortisol levels, an ACTH stimulation test to measure the response of the adrenal glands, and abdominal ultrasounds to check for the presence and severity of tumors.
Treatment of Cushing’s Disease
Treatment will depend upon the underlying cause of Cushing’s disease. If the disease is iatrogenic, your pet will be usually be tapered off medications under the supervision of your veterinarian. When Cushing’s disease is caused by a tumor of the pituitary gland, ongoing medications such as trilostane are often prescribed to suppress cortisol production.
Cushing’s disease caused by a tumor of the adrenal gland is generally the most difficult to treat. Your veterinarian may recommend abdominal surgery to remove tumors. If this is not possible, medications will be prescribed to manage your pet’s condition.
Prevention of Cushing’s Disease
Aside from minimizing the use of corticosteroids, there is no reliable way to prevent Cushing’s disease in pets. The best way to protect your pet is by practicing vigilance and consulting with your veterinarian if you notice any potential symptoms of the disease. Early diagnosis and treatment of Cushing’s disease can lead to a good prognosis in many cases.
