Rottweiler lying on floor
Some diseases are really difficult to diagnose, even for veterinarians. I’ve been practicing for more than 30 years, and I overlooked one such condition in my own dog.

My canine cocktail Quora is 11 years old, and until recently I thought she was just slowing down when she stopped charging ahead on our walks through our property. But then I noticed she was shivering a bit, and although she had a crazy appetite, she just wasn’t all that excited about her food.

I realized that Quora’s hormones must be out of whack and when we had her tested, sure enough, she had Addison’s disease (named after Thomas Addison, the 19th-century British physician who first described the disease in humans). Now that she’s on medication for it, it’s like she has brand-new batteries.

Mystery Disease

Addison’s disease, also known as hypoadrenocorticism, occurs when the adrenal glands don’t secrete enough cortisol and other steroids. There’s often no apparent cause of Addison’s disease. In some cases, however, it may be immune-mediated, or it can occur in response to drugs given to treat another condition. It may also result from damage to or destruction of the glands by some other illness or from trauma or inflammation.

The hormones secreted by the adrenal glands are involved in helping to regulate normal body functions such as metabolism, fluid and electrolyte balance for kidney function, blood pressure, appetite stimulation and more. When those hormones aren’t on the job, dogs can develop a variety of health problems. Addison’s isn’t common, thank goodness, but trying to get a handle on it can really put veterinarians through their paces.

The problem is that symptoms can differ wildly from dog to dog — and in some cases, Addison’s can look like other diseases. Signs such as lethargy; muscle weakness; lack of appetite; drinking and urinating more than normal; occasional vomiting and diarrhea; and weight loss are common to many other disorders. There’s a reason that Addison’s is nicknamed “The Great Pretender.”

If the disease goes unrecognized, though, the adrenal glands become less and less functional. Eventually, dogs with the disease may suffer sudden collapse, known as an Addisonian crisis. They require immediate aggressive treatment to survive. Fortunately, with early diagnosis and treatment, dogs with Addison’s disease, such as Quora, can have an excellent prognosis.

Diagnostic Clues

Although it can affect any dog, we usually see Addison’s disease in young or middle-aged female dogs. Certain breeds seem to be more at risk: Standard Poodles, Portuguese Water Dogs, Bearded Collies, Great Danes, Labrador Retrievers, Rottweilers, Soft Coated Wheaten Terriers and West Highland White Terriers top the list. The disease can also occur in cats, but it’s relatively rate.

If your veterinarian suspects Addison’s disease, it can be confirmed with what’s called an ACTH-stimulation test. This is the administration of ACTH (adrenocorticotropic hormone) to see if the adrenal glands are then able to respond by secreting cortisol.

Other diagnostic tests that may be useful include a complete blood count (CBC) and a serum chemistry panel, including electrolyte analysis. These can help to rule out other conditions such as gastrointestinal disease or acute renal failure as well as to discover the presence of common abnormalities associated with Addison’s, such as low sodium and high potassium levels. In some cases, chest radiographs and an electrocardiogram (ECG) may be helpful in spotting the presence of other related abnormalities.


Most dogs with Addison’s disease need an initial treatment of daily oral hormone replacement for several weeks. They will need to continue some level of glucocorticoid and mineralocorticoid supplementation for the rest of their lives, combined with regular follow-up exams and blood work to make sure their condition remains stable.

If your pet is being managed for Addison’s, be aware that stress from situations such as boarding, travel or surgery can cause flare-ups. Dogs may need additional glucocorticoid supplementation in those instances.

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