The Great Pretender: Hypoadrenocortism (aka Addison’s Disease)
September 4, 2019
Hypoadrenocortism, otherwise called Addison’s Disease, occurs when the adrenal glands are not making the hormones mineralocorticoids and glucocorticoids. Mineralocorticoids regulate electrolytes such as sodium and potassium in the body. Glucocorticoids, such as cortisol, are necessary for proper metabolism of fats, proteins, and carbohydrates.
What is Addison’s Disease?
Primary Addison’s Disease occurs when an animal’s immune system attacks it’s adrenal gland and destroys it. This immune system attack can be set off from many things, like cancer, trauma, or a vascular event.
Secondary Addison’s Disease occurs when the pituitary or hypothalamus are not signaling the adrenal glands to release hormones. This can be because these parts of the brain are diseased due to a congenital defect, inflammation, or cancer.
Addison’s Disease typically occurs in younger to middle-aged dogs. It is also more common in females but can occur in males. Some breeds that are predisposed include Labradors, Retrievers, Standard Poodles, and Collies.
What are warning signs of Addison’s Disease?
Clinical signs of this disease are the waxing and/or waning of vomiting, diarrhea, weight loss, lethargy, weakness, anorexia, and shaking. In an Addisonian crisis, the animal will possibly have low blood pressure, a low heart rate, dehydration, collapse, or be in shock.
Diagnosis
Your veterinarian will perform some of the following tests to diagnose Addison’s Disease
- Chemistry panel: This test shows increased kidney values, elevated potassium and low sodium, low protein levels, low cholesterol, low glucose, and high calcium.
- CBC: This test shows a lack of stress changes which typically causes an increase in neutrophils and monocytes and a decrease in lymphocytes. A mild anemia may also be shown.
- Baseline Cortisol: This test will be low, indicating lack of cortisol in the blood.
- ACTH stimulation test: This test is the disease-specific test used to verify a diagnosis of Addison’s.
Why is Addison’s Disease called “The Great Pretender”?
The changes that can be associated with Addison’s Disease can be misleading; results from the previous listed tests actually be interpreted as other diseases, as listed below.
Abnormalities of Addison’s Disease Include:
- Low Blood Glucose
- Elevated Kidney Values
- Electrolyte Changes
- Low Heart Rate
- Low Blood Pressure:
These same symptoms can also be signs of other diseases including:
- Low Blood Glucose: Toxins, sepsis, cancer, kidney failure, starvation
- Elevated Kidney Values: Dehydration, kidney failure, urinary obstruction
- Electrolyte Changes: Kidney failure, vomiting and diarrhea, pyometra, parasites, diabetes, toxins
- Low Heart Rate: Cardiac disease, toxins, medications
- Low Blood Pressure: Dehydration, cardiac disease, shock, toxins, trauma, hemorrhage
Waxing or waning signs alone can cause confusion for both owners and veterinarians as to what could be causing the clinical signs.
Treatment
If a pet experiences an Addisonian Crisis, they will go into crisis and require emergency care. Typically, intravenous fluids, injectable steroids, Gastrointestinal (GI) medications, and antibiotics are used. Blood pressure medications and plasma may also be warranted in severe cases.
Pets with Addison’s Disease will require lifelong treatment with medications; these drugs will substitute the mineralocorticoids and glucocorticoids that their body is not producing.
- To substitute the mineralocorticoids, pets have two options: fludrocortisone, a daily, oral pill or DOCP, an injection that is required every 28 days.
- To substitute the glucocorticoids, oral pill, prednisone, is typically used daily.
If your animal is diagnosed with Addison’s Disease, the prognosis is overall good with continued treatment and close monitoring.