Cushing's Disease (Hyperadrenocorticism)

Cushing's Disease (hyperadrenocorticism) in dogs is a condition that results from the chronic overproduction of too much glucocorticoid in the body. In the normal dog, the pituitary gland produces a hormone called ACTH, which stimulates the adrenal gland to produce the glucocorticoid hormones necessary for the function of many systems in the body. If something goes wrong in the pituitary gland or adrenal gland and too much glucocorticoid is produced, then Cushing's disease develops. This is a very complicated disease with a wide range of symptoms and causes. Signs include:

  • Increased water consumption and urination(called polyuria/polydipsia)
  • Increase in appetite (called polyphagia)
  • Abdominal enlargement (potbellied appearance)
  • Hair loss and thin skin (called alopecia)

DamonTesting for Cushing's

There is no one specific test that diagnoses Cushing's Disease. A history of certain clinical signs, physical examination changes, and certain alterations in routine lab work may cause suspicions. Patients who have experienced weight gain, muscle wasting, a pot-bellied appearance, loss of hair, and increases in drinking (polydipsia) and urination (polyuria) may cause concerns. Likewise, an increase in white blood cell count or platelet count, increase in the liver enzyme alkaline phosphatase (ALP also called SAP or serum alkaline phosphatase), increased blood sugar, increased cholesterol, and dilute urine can occur in patients with Cushing's disease. There are several additional tests that your veterinarian may perform to diagnose Cushing's Disease:

  • Low Dose Dexamethasone Suppression test (LDDS) - a blood test that uses a low dose of dexamethasone to stimulate cortisol production. Blood is taken in several hour intervals to compare to previous levels of cortisol
  • High Dose Dexamethasone Suppression test (HDDS) - a blood test that uses a higher dose of dexamethasone to stimulate cortisol production. Blood is taken in several hour intervals to compare to previous levels of cortisol
  • ACTH Stimulation Test - a blood test that measures the effect of ACTH stimulation on blood cortisol levels. Blood is taken in several hour intervals to compare to previous blood levels of cortisol
  • Urine Cortisol/Urine Creatinine Ratio - urine is sampled for a ratio of cortisol vs. creatinine

Treatment Options

There are several different treatment options for Cushing's Disease. Because the disease can originate in either the pituitary gland (in the brain) or in the adrenal gland, specific additional tests may be necessary before a  treatment option is selected. 

  • Oral Medication - medication with trilostane or Lysodren can be utilized. Lysodren has higher side effects, but can be less expensive over the life of the pet. Trilostane is more expensive with fewer side effects and typically needs to be given at a higher frequency than Lysodren after the initial treatment period. Neither oral medication is as effective on adrenal-dependent Cushing's than Pituitary Dependent Cushings. You will need to consult with your veterinarian for the best treatment option for your pet
  • Radiation - typically used on small pituitary tumors
  • Surgery - the affected adrenal gland is removed; usually, after medication to reduce the clinical signs of Cushing's Disease. Alternatively, Transsphenoidal surgery is used to remove a pituitary tumor. This surgery is performed at several specialty hospitals across the US. Typically, surgical removal of the tumor eliminates the need for lifelong medication.

HazelPrognosis

The prognosis for pituitary-dependent Cushing’s disease with treatment is usually good. Some signs will disappear quickly and others gradually. Certain clinical signs usually return to normal in a few weeks whereas the full return of the fur may take several months. With pituitary surgery, roughly 85 to 95 percent of dogs who have the tumor removed have hormonal remission. This means the hormonal imbalance and the symptoms associated are cured, and the neurological symptoms can be alleviated. Surgery can be potentially curative for dogs with adrenal tumors.  

 

 

Want to learn more about Cushing's and whether your pet is at risk? Contact us for an appointment.