Pet Hormonal Disorders
Hormones produced by the endocrine glands affect many body processes. Animal Dermatology Center of Chicago will work with your pet’s regular veterinarian to diagnose your pet’s health problems that are caused by hormonal disorders.
Cushing’s Disease (Hyperadrenocorticism)
Download our handout on Cushing Disease.
Cushing’s syndrome is a disease caused by an overproduction of cortisol by the adrenal gland and can occur in two different forms: pituitary-dependent hyperadrenocorticism or by an adrenal tumor. The pituitary gland is a small structure located just above the mouth at the base of the brain and secretes a hormone called ACTH, which causes the adrenal gland located in the abdomen to secrete cortisol and other hormones.
In normal dogs, the cortisol triggers the pituitary gland to decrease ACTH production. If there is a tumor present on the pituitary gland (pituitary dependent hyperadrenocorticism), ACTH levels are not decreased by even the highest levels of cortisol. This results in an overproduction of cortisol. In dogs, pituitary tumors occur in 85–90% of cases of hyperadrenocorticism, and tumors of the adrenal gland occur in 10–15% of cases. Cases caused by pituitary tumors are usually treated with oral medication. Adrenal tumors are removed surgically.
Hyperadrenocorticism can be diagnosed by blood tests. Different types of tests are available that provide various facets of information and are selected based upon the individual patient. These tests may need to be repeated to verify if the disease is present. There are many complications of hyperadrenocorticism, some of which can be life threatening.
The most common form of therapy for Cushing’s disease is the drug mitotane, which shrinks or destroys the adrenal gland so that it cannot produce as much cortisol. Tests are done throughout the treatment to determine how effective the drug is on the adrenal gland. Other drug therapies such as trilostane may be used for hyperadrenocorticism in some cases. Our veterinarians can discuss these testing procedures and treatment options with you.
Hypothyroidism
Download our handout on Hypothyroidism.
Hypothyroidism is a hormonal disease that involves the thyroid gland located in the neck. It is seen mostly in large breed dogs. The primary cause of hypothyroidism is a response of the immune system directed toward the thyroid gland that results in less thyroid hormone being produced.
Because thyroid hormone is involved in all major aspects of metabolism, clinical signs can involve multiple body systems. Weight gain and fluctuations in body temperature, such as heat seeking, are common complaints from owners with hypothyroid pets. Dermatologic signs are very similar to other hormonal disorders but include:
- hair loss involving the trunk
- excess scale and dandruff
- recurrent skin infections
Diagnosing hypothyroidism can be challenging, making it an over-diagnosed disease. Confirmation is based on your pet’s history, clinical signs, and blood tests. Because many other diseases and medications can artificially lower thyroid hormone levels, they must be taken into consideration before we can make an accurate diagnosis. A comprehensive blood panel evaluating multiple aspects of thyroid gland function is recommended rather than a single basic thyroid test.
Management of hypothyroidism includes life-long required medication. A hormone supplement is given once or twice a day after the medical condition is under control. Routine blood work is needed on a regular basis to ensure that hormone levels are within normal ranges.
