Registered Standard Poodles with Addison's Disease (Hypoadrenocorticism)
mode of inheritance: recessive
Addison's disease (Hypoadrenocorticism)
Addison's Disease is a disease of the adrenal glands, usually caused by the immune mediated destruction of the adrenal glands. It affects dogs of all breeds and mixed breeds. Unfortunately, there is a very high incidence of this disease in Standard Poodles, although Miniature and Toy Poodles can also be affected.
Ongoing studies at the University of California - Davis have confirmed the high heritability in Standard Poodles; both parents must carry the recessive gene (or trigger gene) in order for a pup to eventually develop the disease. If only one parent carries the recessive gene, a puppy cannot inherit the disease but if they receive the recessive gene, they will also be a carrier.
At this time there is no test to identify carriers. There is no line or color of Standard Poodles that is not affected by Addison's and no dogs that can be certified as "clear" of the disease. Breeders who test for Addison's are only confirming that their dogs do not have the disease at the time of the testing. Addison's can strike at any age, so testing for Addison's does not guarantee that the dog will not develop Addison's later in life, nor does it guarantee that any puppies will not develop Addison's. That is why it is so important for breeders to know in great detail about the health of the dogs in the pedigrees of those they intend to breed to ensure low risk breedings and also to avoid perpetuating the carrier genes.
Addison's Disease affects males and females equally in Standard Poodles, and is frequently diagnosed in dogs less than a year old. This is important for Poodle owners to remember. Many vets fail to consider it for males or puppies, since the literature suggests that 75% of all affected dogs are middle aged females.
Untreated Addison's is a true medical emergency since death can come swiftly. However, with a timely diagnosis and lifelong medication coupled with careful management of stress, an Addisonian can lead a good life with normal life expectancy.
Symptoms of Addison's frequently begin with vague gastrointestinal problems. The most common symptoms of Addison's are a loss of appetite, vomiting, diarrhea, weakness, depression and lethargy. Other common signs include a painful abdomen, excessive thirst and/or urination, shaking, low body temperature, signs of dehydration or shock. Most dogs don't exhibit all these symptoms and another hallmark of Addison's is that in the early days the symptoms can come and go.
The only definitive test for Addison's is the ACTH stimulation test. Sometimes a regular blood chemistry will show the characteristic low serum sodium and high serum potassium associated with Primary Addison's. However, this imbalance is not always present in the early days and will not be present at all in the case of Atypical Addison's, where only part of the adrenal glands fail.
Because Addison's Disease is known as the Great Imitator, with vague and nonspecific symptoms, getting a diagnosis can be elusive and expensive. Abnormalities in the bloodwork of an affected dog will frequently lead to a misdiagnosis of kidney failure. Many other dogs undergo barium x-rays or exploratory surgery looking for an impaction or foreign object in the digestive tract. Dogs may present with heart abnormalities or symptoms suggestive of cancer. Once treatment is started, most of these other vague symptoms usually disappear and the bloodwork will return to normal.
Whenever faced with one or more recurring symptoms mentioned above, it is wise to ask for an ACTH stimulation test before going for more expensive and invasive procedures. This is a relatively inexpensive test performed in a veterinarian's office.