Perhaps it’s easiest to identify with pets when they suffer the same health problems as we do. Addison’s disease is more common in dogs than in people, though still relatively rare. About three dogs in a thousand suffer from it. But the ones that have it are diagnosed and treated just as people are. (Cats almost never get it: Fewer than 40 cases have been reported in the literature in the last 40 years.)

Who’s Likely to Have Addison’s Disease?

Hypoadrenocorticism, to give the condition its formal name, can strike any dog at any age. Certain breeds seem more at risk, including Poodles, Portuguese water dogs, Bearded Collies, Nova Scotia Duck Tolling Retrievers, Saint Bernards and various terriers such as Westies, Wheaten and Airedales. It’s inherited as an autosomal recessive trait, which means abnormal genes from both parents must be present.

Addison’s disease most commonly occurs in young to middle-aged dogs, though it can theoretically occur at any age, starting from as young as four months old. There is a slight female predisposition.

Adrenal Glands Cause the Problem

Adrenal glands have a lot of tasks. These glands, located at the top of each kidney, produce hormones that help regulate an animal’s metabolism, immune system, blood pressure, response to stress and other functions. There are two anatomic regions, the cortex and medulla, which produce different hormones.

One class of hormones is glucocorticoids, which regulate levels of glucose, protein and fat. Another important class is mineralocorticoids, which regulate electrolyte levels. When the adrenal glands don’t make enough of both types of hormones – an animal gets Addison’s disease.

Most cases are primary, meaning there’s an immune-mediated destruction of the adrenal glands. Less commonly, certain drugs such as mitotane and trilostane (treatment for Cushing’s disease) can cause iatrogenic hypoadrenocorticism. Rarest of all is secondary hypoadrenocorticism, which occurs due to diseases in the pituitary gland or hypothalamus.

What Does Addison’s Disease Look Like to an Owner?

Vets call hypoadrenocorticism “the great pretender,” because you can’t tell a dog has it by looking at him. Vague clinical signs such as lethargy, vomiting, inappetence, diarrhea and weakness could mean many things.

A vet will often perform an ACTH stimulation test, the only test that gives a reliable diagnosis. The doctor injects a synthetic version of adrenocorticotropic hormone (ACTH), which should trigger the production of cortisol in the adrenal glands in a healthy patient. Two blood samples are taken to measure cortisol levels; if the cortisol levels don’t meet a certain range, then a diagnosis of Addison’s disease is made.

General blood work might also give clues, including elevated kidney values, electrolyte derangements (low sodium, high potassium), white blood cell count changes, low albumin or low cholesterol levels.

How Does One Treat Addison’s?

The disease can develop slowly at first, though a crisis can be triggered by stress such as illness or injury. In fact, Sometimes the signs of Addison’s disease appear suddenly; these patients can present to hospitals in a life-threatening state and need to be treated immediately.

Acutely sick dogs need hospitalization, rehydration and injections of glucocorticoid and mineralocorticoid (DOCP), plus supportive care. They usually improve in two to four days.

Addison’s disease isn’t curable, but it’s a treatable lifelong condition. And many dogs can pull through the initial crisis if treated in time.

A Positive Prognosis

Long-term management involves daily steroids to replenish the cortisol hormone deficit, and monthly DOCP injections to maintain normal electrolyte levels. In the case of iatrogenic hypoadrenocorticism, the vet will want you to stop the offending medication and treat it as above.

The prognosis for Addison’s patients is favorable to excellent. Length and quality of life generally won’t be affected, if medications are given on time. (It’s important not to miss them.)

If a dog undergoes a prolonged stressful event – e.g., boarding, illness, even a big house party – the vet may recommend increasing the daily steroid dose: Cortisol helps the body cope with stress. When the stressor goes away, the dog can go back to their usual lower dose.

Charlotte Animal Referral and Emergency operates as the pet equivalent of a human medical center. CARE offers all types of treatments, from emergency care 24 hours a day and 365 days a year to board-certified specialty attention, once you get a referral from your primary veterinarian. We hope you’ll take a visual tour of the practice at carecharlotte.com/tour.

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