Adrenal Gland Disease – Addison’s

Many people have heard of organs such as the kidneys or liver, but there is a smaller organ that can be very problematic if it is not functioning properly; the adrenal glands.

Adrenal glands are a pair of glands situated somewhat above the kidneys. They are responsible for producing hormones to help regulate blood pressure, responses to stress, metabolism, and the immune system. Among their multiple functions, the adrenal glands produce hormones called corticosteroids. A type of corticosteroids, glucocorticoids (cortisol), act on sugar, fat, and protein metabolism to allow the body to burn (rather than store), so they are ready for a fight or flight situation. Another type of corticosteroid, mineralocorticoids, helps regulate electrolytes sodium and potassium to support blood pressure.

If the adrenal glands do not produce enough corticosteroids, the body can have life-threatening consequences. This is called hypoadrenocorticism, also known as Addison’s (a disease which the 35^th U.S. President, John F. Kennedy was known to have). Most of the time, both the mineralocorticoids and glucocorticoids are not being produced; but sometimes, only the glucocorticoids are deficient. We do not always know why this happens, but the most common reason is an immune-mediated destruction of the adrenal glands. Other possible causes include trauma, infection, cancer, and medications to treat the “opposite” disease, hyperadrenocorticism, also known as Cushing’s disease.

Most pets will present as if they are in shock – they are often weak and dehydrated and will often have some degree of GI upset (vomiting, diarrhea, poor appetite). They can act painful and have high or low heart rates. Sometimes, signs can be more chronic and vague – they simply are “not doing well,” but often they present as a crisis. Dogs are often relatively young (around 4-5 years of age) and female, but it is important to note that any dog can be affected. Certain breeds are more prone than others as well. This disease is very rare in cats, but typically will occur in those younger than 5 years old.

Diagnosing is not always straightforward and will require a special lab test to confirm. Depending on how much of the adrenal gland is affected and how low the hormone levels are, the baseline lab work can have vague changes. Often the kidney values are elevated and the blood sugar can be low. The electrolytes are often in disarray. A classic finding is very high potassium and very low sodium, however, if only the glucocorticoids are deficient, the electrolytes can be normal. In addition, a heavy whipworm infection can cause the same electrolyte changes and clinical signs. Therefore, a confirmatory to measure the amount of cortisol is used – this test will be normal in dogs with whipworm infections.

The treatment is replacing the hormones that the adrenal glands are not producing. The most common way to do this involves giving an injection every 25-30 days to replace the mineralocorticoids as well as a low dose of daily steroids to replace the glucocorticoids. Electrolytes are monitored often at first until the proper dose and frequency of medicine is achieved. Treatment is lifelong.

Prognosis with treatment is typically excellent. It is important to note that some stressful situations (either concurrent medical illnesses or psychological stress) could require a temporary increase in supplementation as the body will require more glucocorticoids to maintain normal functions.