(hypoadrenocorticism)

Westonka Animal Hospital & Laser Surgery Center
Mound, MN
Phone: (952) 472-4900
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Hypoadrenocorticsm
Also referred to as “Addison’s Disease”
Adrenal
The adrenal gland is so named because it is located just forward of the kidney Gland
("renal" means kidney). The center of the gland is called the "medulla" and the
outer area is called the "cortex". While both areas produce hormones,
Addison's disease concerns the hormones produced by the cortex. These Adrenal Dog
hormones are called "corticosteroids" and “Mineralocorticoids”.
Corticosteroids are the hormones that enable us to adapt physiologically to stress. The "Glucocorticoids" (such as cortisol and related synthetics, such as
prednisone and dexamethasone) work on the mechanics of sugar, fat, and protein metabolism. They gear the metabolism towards the preparation of
burning (rather than storing) fuels so as to be ready for a sudden "fight or
flight" situation. In other words, they prepare the body to handle a stressful
The "Mineralocorticoids" (such as aldosterone and related synthetic
fludrocortisone acetate) influence the balance of the electrolytes: sodium and potassium. As a general biological rule, where there's sodium or salt, there's water. When the mineralocorticoids circulate as part of the "fight or flight" preparation, sodium is conserved in anticipation of blood loss so that there will be extra fluid in the vascular compartment (spare blood). When sodium is conserved by the action of mineralocorticoids, potassium is lost in order to maintain the normal biological sodium-potassium balance. This whole picture of fat mobilization, sodium conservation etc. which is part of the "fight or flight" preparation is far more complex than can be reviewed here but the bottom line is: Normally, corticosteroid hormones are needed to adapt to stressful situations and without these hormones, even small stresses could lead to physiologic disaster. Normally, sodium is conserved through the action of mineralocorticoids to help the maintain a reserve of water volume. To maintain a normal electrolyte balance, potassium is eliminated as HYPOADRENOCORTICISM (ADDISON'S DISEASE)
In animals with Addison's disease, there is a deficiency of the corticosteroid and mineralocorticoid hormones. The exact cause is unknown but in most cases, it is thought to be an auto-immune disorder. That is, the body’s immune system is recognizing a normal tissue (in this case, the adrenal gland cortex) as being “foreign” (or not normal to the body) and consequently the immune system tries to destroy the “foreign tissue”. This immune system destruction of the adrenal cortex is thought to be the most common cause of hypoadrenocorticism. However, some medications can also destroy the adrenal cortex. These are ketoconazole or Lysodren. Fortunately, the disease can be managed with the administration of corticosteroid hormones and/or mineralocorticoids even if the cause of CLINICAL SIGNS
Patients are usually young (age 4-5 years) female dogs. (This disease occurs in cats but is very rare.) At first signs are
very vague - listlessness, possibly some vomiting or diarrhea. This disease has a reputation for being so vague that it can mimic many other diseases. As a matter of fact, many in the veterinary community refer to the disease as the “great Ultimately, the disease results in a phenomenon known as the "Addisonian crisis". The animal collapses in shock due to
its inability to adapt to the caloric, water loss, and circulatory requirements in stress. Blood sugar may drop dangerously low. Because there is not enough sodium conserved to exchange for potassium, potassium levels soar to maintain the electrolyte balance. Increased potassium levels disrupt the heart rhythm. Heart rate slows, arrhythmias result. The MAKING THE DIAGNOSIS
Veterinarians are usually presented with a young animal in shock. There is usually no history of trauma or toxic exposure so general treatment for shock is initiated. This consists of rapid administration of fluids (usually lactated ringers solution which has little potassium and a moderate amount of sodium) plus some glucocorticoids. By coincidence, this also happens to be similar to the specific treatment for Addison's disease so that often the patient simply recovers without the The blood panel will come back showing elevations in the renal parameters (BUN and creatinine) and thus with the elevated potassium is suggestive of acute renal failure, a condition with an extremely poor prognosis. The veterinarian may become suspicious of another diagnosis as the patient will respond well to fluid administration and most renal failure The only definitive test for Addison's disease is the ACTH stimulation test. The patient receives a dose of ACTH, the pituitary hormone responsible for the release of corticosteroids in times of stress. A normal animal will show an elevation in cortisol in response to ACTH while an Addisonian has no corticosteroids to respond with. This lack of response is diagnostic for Addison's disease; however, a false positive may be obtained if corticosteroids have been used in the treatment of the crisis prior to the test. Only dexamethasone does not interfere with the assay for cortisol; if any other steroid has been used, the test will not be valid for at least a couple of days. TREATMENT AFTER THE CRISIS
The most important aspect of treatment for hypoadrenocorticism is the replacement of the missing mineralocorticoids hormones. One way to do this is with oral(brand name is “Florinef”).is given usually twice a day at a dose determined by the patient's sodium and potassium blood tests. At first, these electrolytes are monitored weekly. When levels seem stable, these blood tests are repeated 2 times per year. Often with time, it will be found that the dose of Florinef needed to control the Addison's disease will increase. This is unfortunate as the medication is relatively expensive. Since Florinef has glucocorticoid activity as well as mineralocorticoid activity, it is not necessary to use Another way to treat this condition is with an injectible medication called "DOCP." This treatment is given approximately
every 25 days. Electrolytes are measured prior to injections at first but testing can usually eventually be tapered to twice Some dogs however, do require glucocorticoid supplementation (such as a low dose of prednisone) whether on Florinef or LONG TERM MAINTENANCE
With either Florinef tablets or DOCP injections, we should monitor your pet’s body carefully. We like to check your pet once every six months (two times per year) with a Hypoadrenocortism Semi-Annual Profile.

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