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What is Addison's Disease?
The correct medical term for this disease is Hypoadrenocorticism. This
term means that there is diminished or lowered hormone production from the
outer part or cortex of the adrenal gland.
What are the adrenal glands?
The adrenal glands are paired glands next to the kidneys. Each gland
of an outer cortex and an inner medulla. The glands produce several vital
substances which regulate a variety of body functions and are necessary to
sustain life. The most widely known of these substances is cortisol,
commonly called cortisone, produced by the outer part of the adrenal
cortex. Also produced by the cortex and equally important is aldosterone,
which is a mineralocorticoid hormone. This hormone regulates the
electrolyte and water balance of the body and is involved in the excretion
of potassium and retention of sodium.
Deficiency of this hormone together with cortisol is referred to as
What causes the disease?
In the dog the main causes are usually the result of direct injury to the
tissue due to hemorrhage, infection or certain autoimmune conditions.
Thus primary hypoadenocorticoism may be immune mediated. It can also occur
when treating Cushing's Disease (hyperadrenocorticism) which can be
thought of as the opposite of Addison's Disease where too much cortisol
and aldosterone are produced.
Addison's disease can also develop if a dog has been treated with long
term steroids for any reason and then is suddenly withdrawn from them.
Another cause can involve the pituitary gland in the brain.
What are the clinical signs?
Signs are usually vague and non-specific. They are often seen in animals
with more common medical disorders such as chronic gastroenteritis or
renal diseases. There may be vomiting and weight loss. A waxing and waning
course with diarrhea, increased thirst and urination is not unusual.
Intermittent shaking episodes are also characteristic.
These animals will often improve with non-specific medical treatment. For
example, the administration of fluids or corticosteroids appears to help
temporarily, but the signs soon return.
Sometimes the condition takes on a much more serious form. There is sudden
weakness, vomiting, diarrhea and sometimes collapse. This is an Addisonian
crisis. Under these circumstances urgent hospitalization will be
How is it diagnosed?
Laboratory tests are necessary, often involving multiple timed blood
samples. Your dog will probably have to be admitted for the day to perform
the necessary tests.
What does treatment involve?
Once diagnosis has been positively established, most dogs can be
successfully treated with oral medications. Your dog's diet and activity
levels can often remain unchanged. The majority of dogs resume normal
lives, ever after a crisis.
It will be necessary to monitor progress carefully, particularly at the
start of treatment. This may involve occasionally hospitalization for
monitoring and follow-up testing.
It must be emphasized that lifelong replacement of both the
mineralocorticoids may be necessary. Some of these medications may have to
be increased during periods of stress, such as when traveling or if the
dog is boarded or has to undergo surgery. In addition we will have to see
your pet at fairly frequent intervals to check that stabilization is
satisfactory. This may involve further blood tests.
If you wish to discuss long-term costs, please do not hesitate to contact
The vast majority of patients with Addison's Disease have a good to
excellent prognosis once the diagnosis has been established and they have
been stabilized with the appropriate drugs. Please do not hesitate to
contact us if you have any questions or concerns.
information sheet is based on material written by Ernest E. Ward Jr.,
© Copyright 2002 Lifelearn Inc. Used with permission under license.
April 28, 2004