Many dogs are not diagnosed with Addison’s disease until they present to the veterinarian in an Addisonian crisis. At this advanced stage of disease, a number of life-saving measures must be taken, including administration of large amounts of intravenous fluids containing sodium, potassium, and glucose (sugar). If the heart rate is critically low from severely elevated potassium levels, it may be necessary to drive potassium from the blood into the cells using insulin. It may also be necessary to provide calcium to protect the heart from hyperkalemia, though administration of calcium itself comes with some risk.
The key to treating an Addisonian crisis is to rapidly replacement the adrenal cortical hormones (i.e. steroids). Intravenous glucocorticoid hormones and intramuscular mineralocorticoid hormone (Percorten) will reverse the devastating chain of events that lead to the crisis.
Long-Term Treatment of Addison’s Disease in the Dog With Mineralocorticoids
The first is Percorten (deoxycorticosterone acetate), a time-release medication injected under the skin. To avoid life-threatening Addisonian crises, Percorten should initially be administered every 25 days as directed by the manufacturer. It is critical to verify appropriate dose and frequency with a series of routine blood tests every 1-2 weeks initially. Some dogs may be treated at greater intervals if the electrolytes are monitored closely during the regulation period. Once the dose and frequency are established, only periodic monitoring is suggested.
The second mineralocorticoid used to treat Addison’s disease in dogs is Florinef (fludrocortisone acetate). Florinef is a daily oral medication with some glucocorticoid activity. Initiation and maintenance procedures are similar to Percorten.
Long-Term Treatment of Addison’s Disease in the Dog with Glucocorticoids
Most dogs with Addison’s disease require a very small (physiological) dose of a glucocorticoid hormone, usually in the form of prednisone, daily or every other day. The dose is adjusted to replace normal production from the adrenal glands, allowing for normal appetite and feeling of well-being. Doses in excess of normal production (pharmacological doses) cause excessive thirst, urination, hunger and immunosuppression and are avoided. Slightly higher doses of glucocorticoids are required during periods of stress (travel, boarding, etc.) or illness/surgery.
Prognosis of Addison’s Disease in the Dog
After management of the acute phase is accomplished, dogs with chronic treatment may live totally normal lives. This disease should not be a limiting factor in the long-term survival if properly monitored and treated. It is therefore critical that you work and communicate closely with your veterinarian at all stages of your pet’s life.