Hypoadrenocorticism

Addison's Disease
Hypo (meaning below normal) attached to adreno (being related to the adrenal gland) and cort (specifying the cortex region anatomically) results in a fancy term suggesing a decrease in production or failure to produce hormones from the adrenal cortex. The cause of this is typically idiopathic meaning poorly understood, and is often considered to have an immune-mediated etiology. It is possible to have destruction from tumor or fungus or other causes, but these are considered very rare. The fact that certain breeds are over represented with this problem (including our beloved Standard Poodle) suggests a genetic component that is not understood. It seems to affect dogs ranging from 6 months of age to 10 years and is primarily seen in females, although males may be affected also
The adrenal cortex is responsible for the production of two major hormones that are both essential for well being. Corticosteroids including cortisol are essential for numerous body functions and are seen primarily in the body's response to all sorts of "stress." Mineralocorticoid deficiencies result in a failure of the kidney's regulation of sodium and potassium and results in severe fluid and electrolyte imbalances. The symptoms of Addison's can all be attributed to the decreases in corticosteroids and the electrolyte (mineral) imbalances. Decreased appetite, vomiting, diarrhea, weakness, depression, dehydration despite increased drinking (due to increased losses through the kidneys, vomiting, and diarrhea), and lethargy may all be seen at various times. Symptoms may wax and wane and often seem to be worse when the animal is stressed. An acute crisis may result in hypovolemic shock, depression, weakness (resulting in collapse in severe instances), slowing of the heart rate (bradycardia) and a failure to maintain body temperature (hypothermia).
These severe symptoms constitute a true veterinary emergency which can easily result in death through cardiovascular collapse. These animals are shocky and very delicate since stress (including the stress of illness) is not handled well due to the lack of cortisol. If approached quickly and aggressively, many animals will respond to supportive care, especially the administration of supportive fluids and correction of the elevated potassium which directly affects the heart. There is not an easy way to recognize Addison's, and sadly it can be missed during a veterinary work up. Electrolyte imbalances (a sodium:potassium ratio of over 27 is very suggestive) and evidence of increased kidney enzymes (azotemia or increases in Blood Urea Nitrogen and Creatinine) are often seen. Because a diagnosis requires specific adrenal testing which is usually not approached during the crisis event itself, and because the symptoms of disease can mimic so many other illnesses ranging from toxicities to kidney disease to viral or bacterial diseases, an animal might be "underdiagnosed" on initial evaluation. All Standard Poodle owners should be aware of this disease and encourage testing immediately if your poodle has symptoms, even if your veterinarian doesn't bring it up of their own accord! This disease is often discussed as the "great pretender" and it is well worth the cost of testing to find out if your friend is suffering from it.
The good news is that Hypoadrenocoricism is treatable with one of two primary drugs, both of which can greatly prolong your poodle's life. Injectable DOCP can be given by your veterinarian every 25 days or so with excellent results. Oral Florinef, a human drug, can also be given daily with good results as well. Many animals will also need to be on prednisone orally either regularly, or at least in times of predicatable stress (traveling, holidays, etc...) While these drugs are a wonderful help, it is important to know that Addison's can NOT be cured. For this reason, we strive to eliminate it from the breed through careful monitoring of all breeding stock and awareness of any reports of the disease to track parents and other ancestors who should be taken out of breeding programs. The heredity of this disease is not understood, so it is not safe to breed any dog who has Addison's in it's background or offspring. It is not easy to test dogs for this disease, and at this point, screening electrolytes or running periodic adrenal function tests are probably the best way to catch dogs who may be tending in this direction.