The adrenal glands are vital for survival. An individual cannot live without a properly functioning adrenal. Improperly functioning adrenals can cause severe illness.
Adrenal secretions help the body respond to and cope with stress. They affect immune responses and inflammation. Body sodium and potassium levels are regulated. Water balance is managed, and metabolism is affected.
The adrenals in the dog are small and shaped like an unshelled peanut. One adrenal is located near each kidney. Each adrenal has two parts with distinct functions.
The inner medulla produces substances like adrenaline, which is an important part of the response to stress. These substances cause an increase in heart rate and blood flow to muscles and brain, and help promote glucose production in the liver.
The outer cortex secretions include steroids like cortisol, regulators of electrolytes and water balance like aldosterone, and low levels of sex hormones.
Adrenal steroids like cortisol affect the metabolism of proteins, carbohydrates and fats, promotes liver glucose production, and suppresses inflammation and the immune response. They can also be an important part of the reaction to stress. Drugs like prednisone have similar effects.
Secretions like aldosterone are involved with regulation of electrolytes like sodium and potassium. They also help with body water balance through their effect on the kidney. Sodium and potassium are essential for proper function of cells including the heart.
With the critical role of adrenal secretions, it is no surprise that there is an intricate regulation process. There are signals from brain areas including the pituitary that trigger secretions from the adrenals. This is based on physiological need and the level of these secretions in the blood allowing for tight control.
Health problems occur when cortisol levels become too high as with Cushing’s disease or when aldosterone and/or cortisol are too low as with Addison’s disease. Excess cortisol is more common and can be caused by a tumor in the pituitary or in the adrenal. The pituitary tumor signals for too much cortisol while the adrenal tumor independently produces cortisol in an uncontrolled way.
Signs of Cushing’s include increased appetite and thirst, increased urination, muscle weakness and wasting, liver problems, pot-bellied appearance and hair loss depending on how high the cortisol becomes and the length of time the problem is present.
Diagnosis is based on a combination of the history, clinical signs, routine blood and urine testing, and specialized adrenal testing. Abdominal ultrasound may be of benefit in diagnosis. Treatment depends on if the problem is in the adrenal or the pituitary. Side effects of drugs like prednisone and dexamethasone when used in excess can cause the same signs as excess cortisol from the adrenals.
When adrenal cells die spontaneously or are destroyed by an autoimmune reaction, adrenal function can become dangerously low. This is known as Addison’s disease. Aldosterone levels may drop too low to adequately regulate electrolytes and water balance. Cortisol levels may also be affected.
Clinical signs are vague and could be attributed to many different diseases making diagnosis challenging. The signs include a waxing and waning weakness, lethargy, vomiting and poor appetite.
Diagnosis involves history, clinical signs, routine blood testing and specialized adrenal testing. Diseases affecting the pituitary can result in low adrenal activity causing signs that look like Addison’s.
Treatment depends on the cause of the low adrenal function. If the problem is adrenal in origin, drugs that have aldosterone like activity and cortisol activity (if needed) are used.
More difficult to recognize are situations where there is adrenal fatigue caused by issues like chronic stress or inflammation. Some dogs with adrenal fatigue have tendencies to be more anxious and are prone to allergies. Adrenal fatigue can be difficult to diagnose.
Integrative support for adrenal problems depends on the specific issue and can range from support with nutritional supplements and herbs to specific medications.
If you have questions or concerns about your dog’s adrenals, contact your veterinarian.
Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. He is also the founder of Colorado Animal Rescue (CARE). In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs.