Cushing's Disease 

Sandra R. Merchant, DVM, Diplomate ACVD        

Carol S. Foil, DVM, Diplomate ACVD

                

Hyperadrenocorticism - Cushing's Disease

Healthy skin and a normal hair coat are the result of many factors, both external and internal.  There are several glands in the body responsible for the production of hormones that are vital for the regulation of other body functions as well as a normal skin surface and hair coat.

 

Cushing's disease results from an overproduction of the hormone cortisol.  Cortisol is produced by the adrenal glands (located next to the kidneys) and stimulated to produce cortisol by the pituitary gland (at the base of the brain).  Disease may be due to overproduction in the adrenal glands by themselves or overstimulation of the adrenal glands by the pituitary gland.

 

Signs associated with Cushing's disease may include increased thirst and urination, a voracious appetite, an enlarged sagging belly, hair loss, lethargy/weakness, panting and sometimes recurrent infections.  Without treatment most dogs will die within one or two years.  With treatment your pet's life can be prolonged, at times to a normal life-span.  Treatment consists of medication to control the overproduction of cortisol by the adrenal gland  or   surgery to remove the abnormal adrenal gland.  Which treatment is best depends upon where the problem is in the dog's body (pituitary or adrenal).  

 

Diagnosis

Cushing's disease can be difficult to diagnose, especially in early cases.  Tests which may be needed may include; complete blood count, chemistry panel, urinalysis, ACTH stimulation test (a 1 or 2 hour test), low dose dexamethasone suppression test (an 8 hour test), a high dose dexamethasone suppression test (an 8 hour test), an ACTH assay, radiographs or CT scan and possibly other  tests!

 

Medical Treatment

INDUCTION: For the first    __   days ______ tablet(s) of Lysodren®  will be given twice daily to decrease the size of the enlarged adrenal glands.  Feed your dog before each pill to be sure the appetite is normal, and if your dog does not eat, do not give the pill, but call us the next morning.  We will set up  a follow-up ACTH stimulation test on your dog after 7 - 10 days, or sooner if he looses appetite or becomes ill as discussed below.  Please schedule the first follow-up ACTH stimulation test (8 am drop-off appointment) on _________(day) , ____________(date). Your dog’s medication will be altered on the basis of the test results as needed.   PLEASE note: Prednisone given within 24-hours of the recheck blood test will make the test invalid, so check your veterinarian if you have any questions.

 

Some dogs are very sensitive to Lysodren,  while other dogs are very resistant.  Although excess cortisol is causing many of the dog's problems, a low level of cortisol is needed to sustain life.  If the cortisol falls below normal, weakness, decreased appetite, vomiting, diarrhea or, rarely, collapse can be seen.  Another drug, Prednisone, can be used to substitute for the needed cortisol in your dog's body.

 

Please either:  1) Give        tablets of prednisone        times daily while giving the Lysodren or, 2) _____Keep the prednisone tablet prescribed to you on hand in case they are needed.  

 

If your dog becomes weak, refuses to eat or vomits while on the Lysodren, please take the following steps:

  1. Discontinue the Lysodren.
  2. Give          tablets of Prednisone            times a day.  This drug can be thought of as an antidote to the Lysodren.  The signs should abate in a few hours.  Please call your veterinarian if this happens.
  3. If vomiting or illness continues in spite of prednisone administration or your pet collapse you must seek veterinary attention immediately.  Treatment by the veterinarian will consist of replacement glucocorticoids (steroids) either orally or by injection, depending on the severity of the signs.  Intravenous fluids may also be needed if collapse is a problem.  

 

MAINTENANCE: After the initial treatment period, if the ACTH stimulation test shows satisfactory reduction in cortisol production,  a maintenance protocol with Lysodren will be instituted.  Usually the maintenance Lysodren will be given 1-2 times weekly.  Although the prednisone is usually not necessary during this time always keep this "antidote" on hand if any of the above mentioned side effects occur.  Give your pet ______ tabs Lysodren on and on. Schedule a recheck examination/ACTH stimulation test in months.

 

Every few months, a recheck and re-evaluation will be necessary since most dogs will require adjustments in their medication dosages.  Remember we are controlling a disease, not curing it.  Therefore cooperation and faithful re-evaluation is in the best interest of your pet.