What is Addison’s disease?

Addison’s disease, or hypoadrenocorticism, is caused by a lower-than-normal production of hormones, like cortisol, by the adrenal glands, which are small glands located near the kidneys. Adrenal hormones are necessary to control salt, sugar, and water balance in the body. 

Addison’s disease occurs less commonly than the opposite condition, Cushing’s disease, which causes the overproduction of cortisol.

What are some of the symptoms of Addison’s disease?

Addison’s disease occurs most commonly in young to middle-aged female dogs. The average age at diagnosis is about 4 years old. The signs of Addison’s disease may be severe and appear suddenly or may occur intermittently and vary in severity.

Signs may include:

  • Weakness
  • Depression
  • lack of appetite
  • vomiting
  • diarrhea
  • increased thirst
  • increased urine production
  • Weak pulse
  • Slow, irregular heart rate
  • Dehydration

When a pet is stressed, its adrenal glands produce more cortisol, which helps them deal with the stress. Because dogs with Addison’s disease cannot make enough cortisol, they cannot deal with stress, so the signs may occur or worsen when stressed.

How is Addison’s disease diagnosed?

A pet’s history, physical examination, and initial laboratory tests can provide suspicion for Addison’s disease, but a more specific test, an adrenocorticotropic hormone (ACTH) challenge, should be performed to confirm the disease. 

Routine laboratory tests often show low blood sodium and high blood potassium. Increased blood potassium can cause life-threatening abnormalities in the heart rhythm. These abnormalities can cause the heart rate to be slow and irregular and can be seen on an electrocardiogram (ECG). 

Sick dogs often show a pattern of changes in their white blood cells called a stress leukogram. These changes are caused by cortisol. The absence of a stress leukogram in a sick dog may be a clue to consider Addison’s disease. The urine is often dilute.

X-rays of dogs with Addison’s disease do not show any specific abnormalities. The heart may appear smaller than normal and rarely the esophagus can be enlarged.

Addison’s disease can sometimes be confused with primary kidney disease.

How is Addison’s disease treated?

There are two stages of treatment for Addison’s disease: in-hospital treatment and long-term treatment.

Very sick dogs with Addison’s disease require in-hospital treatment, including intravenous fluids, cortisol-like drugs, and drugs to neutralize the effects of potassium on the heart. 

Long-term treatment involves the administration of hormones in one of two forms: a daily pill or a shot administered about every 25 days. Because dogs with Addison’s disease cannot produce more cortisol in response to stress, stress should be minimized whenever possible. It may be necessary to increase the amount of hormones given during periods of stress (e.g., boarding, surgery, travel, etc.). 

What is the prognosis for an animal diagnosed with Addison’s disease?

With appropriate treatment for Addison’s disease, dogs can live a long and happy life.

This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian. Washington State University assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.

Where can I get help if my dog has Addison’s disease?

Our board-certified veterinarians and specialists can help you get an accurate diagnosis and develop a treatment plan. Call 509-335-0711 to schedule an appointment or for more information.