Cushing's Syndrome is a condition caused by the excessive production of cortisol.  

Cortisol is a hormone that is normally produced by the adrenal glands (two small organs located near the kidneys). The adrenal glands are under the influence of the pituitary gland which is situated near the brain. The pituitary gland releases ACTH (a hormone) that signals the adrenal glands to produce cortisol.

Cortisol is required by the body to sustain various functions.  An excess of cortisol results in a variety of signs including changes in behavior and appearance. 

What causes hyperadrenocorticism?

The syndrome develops due to changes in the pituitary gland or in the adrenal gland(s).

  • Pituitary gland - the most common reason for Cushing's syndrome to develop is due to tumor growth on the pituitary gland. With this tumor growth and enlargement of the pituitary gland, there is an excessive release of ACTH which results in excessive stimulation of the adrenal glands leading to excessive cortisol in the body. These tumors are generally benign and rarely cause problems other than Cushing's syndrome. In a small percentage of cases, these tumors can become very large and cause other serious problems including blindness.
  • Adrenal gland(s) - the lesser common reason for Cushing's syndrome to develop is due to  tumor growth on one or both of the adrenal glands. With tumor growth, there is excessive cortisol production.
What are signs of Cushing's syndrome?

Common signs that can be noticed by the owner include:
  • Increased thirst and urination
  • Urinary incontinence
  • Increased or ravenous appetite
  • Excessive panting
  • Muscle weakness
  • Pot-bellied appearance
  • Thinning of the skin
  • Hyperpigmentation of the skin
  • High blood pressure
  • Other skin disease
  • Concurrent diabetes mellitus can be seen
Learn more about the Signs of Cushing's Syndrome

How is hyperadrenocorticism diagnosed?

A veterinarian will recommend routine screening lab tests including a blood count, chemistry profile and a urinalysis to make an assessment of the pet's health. Based on these routine test results, coupled with the pet's signs, additional testing may be recommended to assess the function of the pituitary and adrenal glands.
 
It's not uncommon for a veterinarian to conduct multiple tests as, sometimes, the results of one test may not give a clear indication as to whether a pet has Cushing's syndrome or not.
 
How is Cushing's syndrome treated?

The treatment options depend on the cause - whether it's pituitary-dependent or due to a primary adrenal gland problem.
  • Medical treatment - there are several medications used to treat dogs with pituitary-dependent Cushing's syndrome. Each has their own benefits and risks and pets require careful monitoring during the treatment process. In rare instances, radiation therapy to shrink a pituitary tumor may be recommended - especially in cases where the enlarging mass leads to other medical problems.
  • Surgery - pets with an adrenal tumor may respond to medical therapy. In many cases, surgery may be recommended to remove the adrenal tumor.
Learn more about Treatment of Cushing's Syndrome

What's the prognosis?

Pets with Cushing's syndrome generally require lifelong management with medication(s) and periodic check ups to monitor for complications or associated conditions that can develop.
Successful control of cortisol levels is essential for the health and well-being of the affected pet.  Associated conditions that can arise or complicate the well-being of the pet include diabetes mellitus, high blood pressure, skin infections, urinary tract infections, and stroke (thromboembolism).