Known also as hypoadrenocorticism, hypocortisolism, and adrenal insufficiency, Addison’s Disease was first found in humans and then later found in dogs. The disease is described as an endocrine system disorder and takes place when the production of corticosteroid hormones decreases to such an amount that the body is no longer able to function normally. The adrenal glands are responsible for producing the hormones and they are located above the kidneys. These glands can stop working due to injury, which can happen in all different ways.
If corticosteroid drugs have been prescribed for some sort of medical situation and are suddenly taken away, an acute Addisonian crisis can occur. The condition is serious because it can move fast to shock and even cardiovascular collapse.
An interesting fact is that Addison’s Disease in dogs is believed to be almost 100 times as common as in humans. Many veterinarians believe that the disease is much less rare in dogs than people think and is in fact just under-diagnosed. The cause of Addison’s Disease isn’t always known, however it seems in most cases it has been brought on by some sort of injury to the adrenal cortex.
It should be stated that whenever the adrenal glands are compromised, Addison’s Disease can occur. A common cause seems to be an auto-immune disorder. There are other causes though, such as long term usage of corticosteroid hormones, overdose of a particular medication, physical injury or trauma of some sort to the adrenal glands, cancer, adrenal tumours, and granulomatous disease.
Addison’s Disease is commonly found when both or one of the adrenal glands one or more of the layers of the cortex is deteriorating.
Perhaps the best thing to do is to prevent any trauma to the abdominal area. Unfortunately there is no surefire way to prevent a dog from getting Addison’s Disease because the cause of the disease itself is still relatively unknown.
Common symptoms include:
- weight loss;
- lack of appetite;
- diarrhea which may or may not have blood in it;
- increased thirst;
- abdominal pain;
- increased urination;
- shaking, shivering or trembling;
- poor coat and skin condition;
- shock; and
Dogs at Risk
Those dogs at higher risk for Addison’s Disease are typically female between the ages of four to six years old. It’s important to note though that any gender or age can be affected. There is no set breed(s) that seem to be more prone to the disease than others, however, it is believed that a few might be at higher risk. These breeds are Labrador Retriever, West Highland White Terrier, Great Dane, Nova Scotia Duck Tolling Retriever, Soft Coated Wheaten Terrier, Basset Hound, Standard Poodle, Portuguese Water Dog, Rottweiler, Bearded Collie, and Leonberger.
Testing and Diagnosis
The veterinarian will begin with a basic physical examination, then a urinalysis and basic blood work. If the results show low blood chloride levels, low blood sodium levels, high levels of circulating blood urea nitrogen, and high blood potassium levels, then a tentative diagnosis will likely be given.
There is only one test that can be done to give a definitive diagnosis and that’s an ACTH stimulation test. In a dog with Addison’s Disease, there will be very low levels of adrenal steroids in its system. The test is done by giving an ACTH to the animal then waiting to see if the adrenal glands have reacted correctly and started to manufacture more corticosteroids. Those dogs that have the disease will not react to the ACTH injection, or have very little reaction because its adrenal glands are damaged.
For a normal healthy dog ACTH is made by the pituitary gland and then stimulates the adrenal glands that will go on to produce other necessary hormones.
Often the symptoms of Addison’s Disease can mirror those of other diseases, so a proper diagnosis must be obtained.
Treatment and Prognosis
Treatment of Addison’s Disease involves being able to correct the electrolyte imbalances. Once this is done, the dog’s health can then be managed. Routine blood work will be necessary for the first while and a monthly injection will be given. It’s important to note that the injections used to treat the disorder usually cause the animal to be quite thirsty, therefore it’s imperative that water is always available so they don’t become dehydrated.
The goal of treatment is to correct the electrolyte imbalances, replace the circulating fluid volumes by reestablishing hydration and stabilize the hormone levels through corticosteroids.
Addison’s Disease is without a cure but that doesn’t mean the dog’s quality of life has to suffer. The key to a positive prognosis is early detection and giving the dog its necessary medication(s). Once the disease has been detected then proper medications can be prescribed and the dog will be on its way to feeling better.