Addison’s Disease in Dogs

Addison’s disease, or hypoadrenocorticism, is caused by insufficient production of adrenal hormones. The adrenal glands are located by the kidneys and produce glucocorticoid and mineralocorticoid hormones. Glucocorticoid hormones, such as cortisol, are responsible for stress responses such as the fight-or-flight response. Mineralocorticoid hormones, such as aldosterone, are involved in regulation of electrolytes such as sodium and potassium.

Common name:Addison’s disease
Scientific name: Hypoadrenocorticism

Diagnosis for Addison’s Disease in Dogs

Signalment
Addison’s disease is typically a disease of middle-aged female dogs. All breeds can be affected. Genetic predisposition may play a role in certain breeds, such as the standard poodles, West Highland white terrier and others.

Incidence/prevalence
Addison’s disease is considered uncommon.

Geographic distribution
There is no known geographic predilection.

Clinical signs (primary, most to least frequent, scientific term, synonyms)
Lethargy, Vomiting, Weakness, Diarrhea.

Clinical signs (secondary, most to least frequent, scientific term, synonyms)
Hyponatremia (low serum sodium concentration), Hyperkalemia (high serum, potassium concentration), Bradycardia (slow heart rate), Hypoglycemia (low blood sugar), Dehydration, Hypotension (low blood pressure).

Causes (scientific, common term)
Immune-mediated (immune system attacking own cells), Infection (rare), Neoplasia (cancer, rare).

Organ systems affected (most to least affected)
Addison’s disease is a multisystemic disease.

Diagnostic tests
ACTH stimulation test, Serum potassium, Serum sodium, Complete blood count.

Differential Diagnosis
Gastroenteritis, Renal failure, Toxin ingestion, Acute pancreatitis, Ruptured bladder, Whipworms.

Treatment for Addison’s Disease in Dogs

Home Care
There is no home treatment for acute Addisonian crisis.

Professional Care
Hypoadrenocorticism can be suspected based on history, physical findings and identification of electrolyte abnormalities. Blood work often reveals elevated potassium and low sodium. However, animals with secondary Addison’s disease may not have these electrolyte imbalances.

Confirmation of the diagnosis requires an ACTH (adrenocorticotropic hormone) stimulation test. ACTH is the hormone produced in the brain that stimulates, or “tells,” adrenal glands to produce and secret cortisol and other hormones. A normal animal will show an increase in cortisol hormone secretion after being given ACTH. Lack of response is diagnostic for Addison’s disease.

Differentiation between primary and secondary hypoadrenocorticism requires additional testing.

Emergency treatment for animals in shock requires intensive intravenous fluids, correction of electrolyte imbalances, maintenance of blood sugar with intravenous dextrose and administration of glucocorticoid medications. Medications may include fludrocortisone (Florinef) or DOCP (Percorten-V) for mineralocorticoid supplementation. In addition, daily oral glucocorticoid supplementation with prednisone is often required. Doses of prednisone may need to be increased at times of illness or stress (such as during boarding, hospitalization or travel).

Action
Addison’s disease treatment requires ongoing veterinary care including medication supplementation and monitoring.

Outcome
With appropriate and consistent veterinary treatment, dogs with Addison’s disease can live a relatively normal life.