Addison's Disease (Hypoadrenocorticism)

What is it?

The adrenal glands, near the kidneys, make cortisol (a stress hormone) and aldosterone (which balances sodium and potassium). In Addison's disease, too little of these hormones is made, most often because the immune system has damaged the adrenal tissue. Less often it follows injury, infection, cancer, a pituitary problem, treatment for Cushing's disease, or abruptly stopping long-term steroids. Breeds at increased risk include Portuguese water dogs, bearded collies, standard poodles, Nova Scotia duck tolling retrievers, Leonbergers, Great Danes, and Labrador retrievers.

What signs should I watch for?

Signs are often vague and may wax and wane: lethargy, vomiting, diarrhea, increased thirst and urination, weight loss, and episodes of shaking. Signs may improve briefly with general treatment and then return. A sudden crisis can cause weakness, severe vomiting and diarrhea, and collapse.

How is it diagnosed and treated?

Routine blood and urine tests often show electrolyte imbalances, and the ACTH stimulation test confirms the diagnosis. Other tests may rule out similar conditions. An Addisonian crisis needs immediate hospital care. Long-term treatment replaces the missing hormones, typically with DOCP injections every three to four weeks (which can be given at home) plus an oral steroid, or with oral fludrocortisone.

Can it be prevented, and what's the outlook?

• Addison's disease cannot be prevented, but it is very treatable.
• Once stabilized on medication, the vast majority of dogs have a good to excellent outlook and resume normal lives, even after a crisis.