Addison's Disease

Hypoadrenocorticism results when the adrenal glands are diseased and not working properly.  The adrenal glands are small glands that sit on top of each kidney.  There are two glands and combined, they are responsible for making various steroids required by the body in order to function properly.  Mineralocorticoids help regulate the body's sodium, potassium, and water levels.  Glucocorticoids affect almost every tissue in the body.  Effects of glucocorticoids range from glucose regulation, protein and fat break-down, making of red blood cells, reducing inflammatory responses, maintaining homeostasis during stress and maintaining blood pressure.

Without these steroids, the body cannot function properly and will die.  The goal of treatment is to supplement the body with these steroids so that the body can return to a normal state of function.  Cats very rarely get Addison's disease.  It is mostly seen in dogs, yet it is not a very common disease.  However, it is a disease that is called "the great mimicker" because the signs can mimic many other diseases and often goes undiagnosed.  Female dogs more commonly get it compared to male dogs, but male dogs are not immune to it.  Addison's is usually, but not always, seen in young to middle-aged dogs.  Any dog can be diagnosed with Addison's disease, however there are some breeds that are diagnosed with it more often.  Standard Poodles, Miniature Poodles, mixed breeds, Labrador Retrievers, Golden Retrievers, Rottweirlers and German Shepherds were more commonly seen in one retrospective study.  However, many veterinarians see various breeds with Addison's disease and thus reluctant to say that one breed gets it more than another.

Signs and Symptoms

The reason Addison's disease is called "the great mimicker" is because the signs and symptoms can be extremely variable and every dog will present differently.  The signs can be mild to very severe.  The signs can even be vague and even suggestive of a more common disorder such as gastrointestinal disease or kidney disease.

The top signs reported by owners are as follows:

Anorexia

Thin/Weight loss

Lethargy/depression

Vomiting

Weak

Diarrhea

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Excessive urination

Painful abdomen

Shaking

Waxing/waning signs (periods of feeling ill followed by periods of normalcy)

As one can see, these signs can be seen with numerous other illnesses and thus makes diagnosing Addison's disease very difficult.  A veterinarian must put it on his/her rule out list when seeing a dog with signs of "just not feeling well".  There are many dogs which will present in full shock, complete with unresponsiveness, low body temperature, low heart rate, and pale gums.

Diagnosing Addison's Disease

As stated before, it can be difficult to diagnose Addison's disease if the veterinarian isn't looking for it.  The diagnosis is made by doing a blood test called an ACTH stimulation test.  This is a series of blood draws made before and after giving a synthetic form of ACTH.  Diagnosis is based on this test but a suspicion of Addison's disease is based on clinical signs as well as a chemistry panel (liver, kidney, glucose and electrolyte levels) and complete blood cell count.  Dogs with Addison's disease can, but not always, have low sodium and chloride values and a high potassium value.  The dog may or may not have a low red blood cell count, a low blood glucose (sugar) value,  and elevated kidney values.  A dog's electrocardiogram (ECG or EKG) may also be abnormal.

The definitive diagnosis comes from the ACTH stimulation test.  Once a diagnosis of Addison's has been made, the dog will need treatment for the test of his/her life.  It is not a disease that will correct itself.

Treatment

If your dog presents to your veterinarian in shock, your veterinarian will treat the dog for shock first and foremost.  This can help the dog feel better until a diagnosis can be made.  For dogs with the vague "not feeling well" signs, your veterinarian will probably wait until the ACTH stimulation results return before treating your dog.  If your dog is diagnosed with Addison's disease your veterinarian will then start treatment for your dog.

The treatment for Addison's disease consists of a shot given every 25-28 days for the rest of your dog's life.  The shot is called DOCP (desoxycorticosterone pivalate), and it is a replacement for the mineralocorticoids.  This will help regulate your dog's electrolytes and water homeostasis.  Some dogs, but not all dogs, will also need glucocorticoids in the form of a pill called prednisone.  Once your dog is stable and feeling better, your dog's electrolytes, blood sugar, kidney and liver values, and red blood cell count will need to be periodically checked.  How often, and what values need to be checked, will be decided by your dog's veterinarian.

Prognosis

The prognosis in dogs has been excellent when diligent owners and veterinarians have treated these dogs.  Owner education is very important because it is a life long treatment and needs frequent blood checks for the remainder of the dog's life.  Dogs that present to the veterinarian in shock can be much harder to treat and the prognosis is guarded for these dogs.  If the dog responds to the shock treatment, the prognosis is better.