What is Addison’s disease in dogs?
As you may have gathered, patients with Addison’s disease have low cortisol levels (and often also low aldosterone levels, which we address soon). In fact, “low cortisol” is included right in the technical name for Addison’s disease which is hypoadrenocorticism. “Hypo” means low, “adreno” refers to the adrenal glands, and “corticism” refers to cortisol production. To understand this disease a bit better, you need to first understand a bit about the adrenal glands and their function.
The paired adrenal glands, located next to the kidneys, are responsible for producing different hormones. These include glucocorticoids, such as cortisol, and mineralocorticoids, such as aldosterone.
The role of cortisol in the body
You may have heard of cortisol, the “stress hormone,” that helps your body get ready to burn fat and sugar in “fight or flight” scenarios. Like anything in the body, too much or too little cortisol is a bad thing. If the dog produces excessive cortisol, he or she has Cushing’s disease in dogs. On the other hand, dogs who produce too little cortisol have Addison’s disease.
The role of aldosterone in the body
One of the other main products of the adrenal glands, aldosterone, helps regulate important electrolytes in the body such as sodium and potassium. This hormone is equally important during times of stress because it causes the body to control electrolytes (mainly sodium) that would normally help the body retain water. This serves to stabilize blood pressure in case of injury.
As a result of their low cortisol and low aldosterone, dogs with Addison’s disease cannot physically respond to stress in an appropriate manner. This can trigger a crisis when they go through a stressful period.
Some dogs are deficient in both cortisol and aldosterone. This is the “classic” or “typical” form of Addison’s disease. However, other dogs only have low cortisol. Their aldosterone levels are still normal. In that case, we say the dog has “atypical” Addison’s disease.
Auto-immune destruction of the adrenal glands (i.e. destruction by the dog’s own immune system) is the most common cause of Addison’s disease. In rarer cases, a tumor or damage to the pituitary gland (i.e. the structure in the brain that sends the signals to the adrenal gland to stimulate them to produce cortisol) can cause Addison’s disease.
Additionally, medications that treat Cushing’s disease such as trilostane and mitotane may overcorrect the body’s excessive steroid production. This can lead to low cortisol levels. For this reason, and others, routine appointments for Cushing’s disease monitoring are so important for dogs taking those medications.
Addison’ Disease in Dogs: Conventional and Holistic Treatment
Addison’s disease is often called the “great pretender.” The symptoms can be chronic, vague, and masquerade as other illnesses. The initial diagnosis is often missed and only discovered after other diagnostic avenues have been exhausted. In any dog that has waxing and waning signs like decreased appetite, weight loss, diarrhea, vomiting, or just general “poor doing,” Addison’s should be on the differential diagnosis list. This is especially true in breeds such as Rottweilers, Great Pyrenees, and Portuguese Water Dogs.