Addison's Disease--Hypoadrenocorticism

Frankie, a two year old West Highland White Terrier, stood on the exam table shaking, head down, and looking miserable. The reason for his visit was listed as the dreaded ADR (for “Ain’t Doin’ Right”) Normally he would be racing around the room with terrier level intensity, and at the moment it was clear that ADR was a good description. He had been eating and drinking, with no vomiting, diarrhea, coughing, or sneezing, but clearly he felt rotten. His physical exam showed no fever, pain, or other abnormalities outside of fairly significant dehydration, but in spite of the lack of obvious findings it was clear that this dog was in trouble.

Blood work was the clincher that saved this dog’s life. Frankie’s potassium levels were very high and his sodium levels were very low. When considered with his symptoms, his age, and his breed it was strongly suggestive of Addison’s disease. We drew some more blood for a special test to confirm the diagnosis, and started him immediately on fluids and medication to get him stabilized. By the next morning you couldn’t tell that anything had been wrong with him. Without the blood work to lead to the diagnosis and treatment, however, he probably wouldn’t have survived the night.

Addison’s disease, or hypoadrenocortisism as it is officially called, was brought into the limelight by President Kennedy, who suffered from the disease, and it happens at roughly the same rate in people as it does in dogs. Problems start when, for unknown reasons, the immune system attacks and destroys parts of the adrenal glands that make hormones that regulate several important body system functions. The hormones that are affected are Aldosterone, which balances the body’s sodium and potassium levels, and Cortisone, which helps the body deal with stress. Once those areas of the adrenal gland don’t work the body gradually becomes so unbalanced that death is inevitable. Addison’s disease has been reported in cats, but it is extremely rare. It is much more common in dogs, especially Westies, Standard Poodles.

Signs of Addison’s disease are notoriously non-specific. Many dogs will be drinking and urinating more than usual, and sometimes they seem less energetic, but often they look and act quite normal until they have a crisis where they often become quite ill and shocky for no apparent reason.

Results of regular blood work can also be notoriously non-specific. A high potassium and low sodium are a big tip-off, but are not always obvious. Often kidney values are elevated. It is common for Addisonian dogs to be misdiagnosed as having kidney disease at first. Because the onset of Addison’s disease usually happens around two to three years of age, veterinarians should always have it in mind as a possibility in any young dog that has blood work suggestive of kidney problems. Definitive diagnosis requires a two-part blood test called an ACTH stimulation test that measures the function of the adrenal glands specifically.

Treatment is straightforward. Affected dogs need to have the hormones that they are not making given to them from outside. We replace the cortisone with very small doses of oral prednisone. We replace the Aldosterone with an injection of a drug called DOCP. The injection releases the hormone slowly over the course of a month and must be faithfully repeated on a monthly basis. People with Addison’s disease often take an oral medication called Florinef. It replaces both hormones with one pill, and humans can usually be treated with one pill once or twice per day. Although dogs can take Florinef, they don’t metabolize it quite the same way people do, so a golden retriever may require five pills twice daily, and still not be very well controlled. The DOCP is not cheap--a big dog could cost more than $100 per month to treat-- but it works very well and dogs that get treated can be expected to live completely normal lives. The biggest problem we have with treating Addisonian patients is that owners see their dog doing so well that they may be tempted to think that he seems just fine, so why do they need to continue with that expensive shot. After the first skipped injection the dog may continue to act normally for a while, but it won’t be long before collapse and crisis occur. A dog in Addisonian crisis is on the razor’s edge between living and dying, and sometimes we can’t treat them in time to save them.