In my very first newsletter of January 2023, I collaborated with my husband, Dr. Gregory M. Kuhlman, DVM, DACVIM on an article about treating our cat, Rosie, for osteoarthritis pain using SolensiaⓇ. That article has been a big hit with cat owners who have been wondering if SolensiaⓇ really works.
I asked my audience to submit any questions they might have about the health of their pets. Dr. Greg is a veterinary internal medicine specialist and has agreed to answer some questions. He absolutely cannot diagnose anything without a physical exam of the pet in question, but he can make general recommendations on what to have your veterinarian investigate.
Whitney, Dekker's mom, was the first to take us up on answering a question. She asked,
I do have a Dekker-specific issue I’ve been trying to sort out 😅 He’s always had trouble putting on weight (diva poodle problems 😅 and too much fat makes him barf/get pancreatitis). His vet says he’s healthy, but she does think he needs to build muscle. I’ve been playing with different food toppers and satin balls to add an extra boost of protein and help him put on some weight, but I’d be eager to hear if y’all have any recipes for food toppers or other suggestions to help a dog bulk up and get some extra nutrients without breaking the bank!
Whitney also related that she often gets remarks about how thin Dekker is. In fact, I probably remarked on it myself when they came to the studio for their session. Just because you think someone's pet is too thin or too heavy, you don't know the real reason(s) behind it unless you're a veterinarian. Please don't judge.
I asked Dr. Greg about Dekker's lack of muscle. He asked "what breed?" "Standard Poodle." "Then he might have Addison's. Ask her to have an ACTH-stimulation test to definitively diagnose it. How's his bloodwork?" I went back to Whitney who said Dekker's blood tests were "normal." Dr. Greg came back with, "Sometimes "normal" isn't normal. The cheaper resting cortisol test will rule it out." "Also, nix the satin balls. They are literally a recipe for pancreatitis." (Many online recipes for "satin balls" contain raw meat and tons of fat. ALWAYS check with your veterinarian before introducing a raw diet for your pet.)
Veterinarians often call Addison's disease, "the Great Pretender" or "Great Imitator" because its signs can often be vague or resemble something else. In a guest post for Dr. Buzby's Toe Grips, Dr. Kathryn Williams, DVM relates the story of Annie, a Border Collie Mix who was in excellent health until she got hold of a piece of bacon. Her bloodwork was normal, just like Dekker's. While Dr. Williams still suspected pancreatitis or severe gastroenteritis thanks to the bacon, she ran a baseline cortisol test, which was quite low. She asked Annie's parents to run additional tests as I describe below, which positively confirmed the Addisonian diagnosis. Dr. Williams started treating Annie for Addison's even before the tests came back because it would do more harm than good to wait. Good thing she did, and Annie was feeling like herself in no time.
What is Addison's Disease?
Addison’s disease in dogs and cats is a disease of the adrenal gland that is life-threatening if not treated. It’s a disease in which cortisol levels drop to dangerously low levels. Specifically, it is a condition resulting from a deficiency of adrenal hormones, also known as hypoadrenocorticism. Cats can also have Addison's disease, but it is rare.
The disease’s cause is unknown, but it is thought to be autoimmune in nature and may be triggered by a viral infection or stress. In pets with Addison’s disease, the adrenal gland does not produce enough cortisol to meet their body’s needs. Symptoms of adrenal gland disease may include vomiting, diarrhea, weight loss, lethargy, low blood pressure, a slow heart rate, and a dull coat. Additional symptoms may include a dark-hued skin coloration due to lack of cortisol production, weakness, irritability, and a decreased appetite. If left untreated, dogs and cats with Addison’s can develop a life-threatening crisis known as an Addisonian crisis characterized by severe dehydration and electrolyte imbalances.
This article discusses what Addison's disease is and how it is diagnosed and treated by veterinarians. We’ve also included references/links to help you understand more about treatment options for pets with this disease.
What Causes Hypoadrenocorticism?
Specifically, the adrenal glands produce cortisol, a steroid hormone that regulates blood glucose levels and electrolyte balance. In Addison’s disease, the adrenal glands do not produce enough cortisol, and sometimes not enough aldosterone, to function normally. The lack of cortisol and aldosterone leads to electrolyte imbalances, hypokalemia (low potassium), hyperpolarization (i.e., impaired ability to regulate heart rate), dehydration, hypercalcemia (i.e., high levels of calcium in the blood), hypoglycemia (low blood glucose levels), and hypoadrenocorticism (i.e., adrenal gland failure).
What are the adrenal glands and what do they do?
The adrenal glands are small organs located on top of the kidneys that produce hormones to regulate metabolism and other bodily functions. When the adrenal glands fail to produce a sufficient amount of cortisol, Addison’s Disease may develop. Destruction of the adrenal gland by a metastatic tumor, bleeding, infarction, granulomatous illness, or drugs like Mitotane or Trilostane that inhibits adrenal activity, may also induce Addison's disease.
Rendering of the anatomy of a male dog showing the location of the kidneys, adrenal glands and pituitary gland, which controls the adrenals. (Image credit: Modification of two images by decade3d on Adobe Stock).
Radiograph (X-ray) of a male cat's abdomen showing the location of the kidneys, diaphragm, intestines, and colon. The adrenal glands are too small and there is too much similar density tissue surrounding them to see them on an X-ray. The scale is in centimeters. (Image credit: Dr. Gregory M. Kuhlman, DVM, DACVIM).
The adrenal gland is made up of two components: the cortex and medulla.
Schematic drawing of an adrenal gland showing its internal structure and the various hormones produced with its layers. (Image credit: designua on Adobe Stock).
Each layer of the adrenal cortex produces a distinct set of steroid hormones, and it is divided into three layers. Mineralocorticoids are produced by the outer layer and help to regulate the body's sodium and potassium salt balance. Glucocorticoids, which help metabolize nutrients and lower inflammation and immune responses, are produced in the middle layer. Estrogen, progesterone, and androgens are all produced by the inner layer.
The adrenal medulla plays a crucial role in response to stress or low blood sugar (glucose). Epinephrine (sometimes called adrenline) and norepinephrine both increase heart performance, blood pressure, and blood glucose while delaying digestion.
What are the symptoms of Addison's Disease?
Addison’s disease is a condition that causes a decrease in energy or appetite, weight loss, depression, and vomiting in both dogs and cats. Other symptoms of Addison’s disease can include excessive drinking and urination, diarrhea, and muscle weakness. A veterinarian must conduct a thorough physical exam to diagnose Addison’s disease. Physical exams may test for signs of dehydration, hypo- or hyperthermia, and muscle weakness. In addition to a physical exam, blood tests and urine tests may also be used to help diagnose Addison’s disease. Symptoms of Addison's disease often do not become apparent until the adrenal glands are about 90% destroyed, according to Dr. John August, a veterinarian at Texas A&M University, where Dr. Greg did his residency in veterinary internal medicine.
Feline Symptoms
Addison's disease in cats is extremely rare, but it can happen. Repeated periods of lethargy, appetite loss, and weight loss are all common symptoms in cats with Addison's disease. A history of vomiting episodes may be seen in some cats. Unlike dogs with Addison's, diarrhea is an uncommon symptom in cats with the disease. Dehydration, weakness, an unusually sluggish heart beat, and a loss of body fat and muscle mass are all symptoms that your veterinarian may detect on a physical exam. Many cats have weak pulses, severe dehydration, and severe weakness, which are all symptoms of shock.
What's an Addisonian crisis?
An Addisonian crisis is a life-threatening complication that can occur when the disease is left untreated. The adrenal cortex produces aldosterone which is important for electrolyte regulation and blood pressure. An Addisonian crisis can occur when 90% or more of the adrenal cortex is not functioning. It requires immediate veterinary intervention to reverse the crisis and restore gland function. Early diagnosis and treatment of Addison’s disease are important to prevent an Addisonian crisis from occurring. If your dog exhibits any signs or symptoms of this condition, be sure to act quickly and consult a vet for help.
Breed susceptibility
Natural hypoadrenocorticism is uncommon in dogs. It is estimated to affect 0.06% to 0.28% of the general dog population. Several breeds, such as Bearded Collies, Standard Poodles, Portuguese Water Dogs, and Nova Scotia Duck Tolling Retrievers, have a higher reported incidence of Addison's disease. Their reported prevalence rates are reported in the table below.
| Breed of Dog | Percentage of Dogs with Addison's disease |
|---|---|
| Bearded Collie | 9.4% |
| Standard Poodle | 8.6% |
| Portuguese Water Dog | 1.5% |
| Nova Scotia Duck Tolling Retriever | 1.4% |
Scott-Moncrieff JC. Hypoadrenocorticism. In: Ettinger SJ, Feldman EC, editors. Textbook of Veterinary Internal Medicine. 7th ed. Vol. 2. St. Louis, Missouri: WB Saunders; 2010. pp. 1847–1857.
Several other breeds, including West Highland White Terriers (WHWT), Rottweilers, Jack Russell Terriers, Saint Bernards, Great Danes, Basset Hounds, Labrador Retrievers and Soft-coated Wheaten Terriers have also been reported to possibly have an increased risk of Addison's disease. Standard Poodles and Nova Scotia Duck Tolling Retrievers have also been shown to have an autosomal recessive inheritance. More recently, Great Pyrenees dogs have also been shown to have a higher risk of Addison's disease.
What is the life expectancy of a dog with Addison's Disease?
The prognosis for dogs with Addison’s disease is good if the disease is diagnosed early and treatment is started promptly. With treatment, pets can lead a normal life. Addison’s disease cannot be cured and requires long-term management. Therefore, it’s critical to take them to the veterinarian regularly for check-ups.
How Does a Veterinarian Diagnose Addison’s Disease?
Veterinarians typically use a medical history and physical examination to diagnose adrenal disease in dogs. A medical history of symptoms is important, as are blood tests to check electrolyte levels, kidney function, glucose levels, and other markers. Other tests, such as an electrocardiogram (ECG), may also be performed. A blood serum biochemistry profile can also be a helpful tool in making a diagnosis, as it can indicate adrenal gland disease. A complete blood count (CBC) may identify mild anemia or a higher than expected lymphocyte and/or eosinophil count.
Urine tests may also be used to detect any changes or abnormalities in the dog's urine, in addition to other tests. Electrolyte levels in the dog's system may be assessed using urinalysis, which may be used to detect Addison's disease. Ruling out any structural issues that may be creating symptoms with X-rays is beneficial. An abdominal ultrasound may be required when Addison's disease is suspected because it will give a clearer picture of what is occurring inside the dog's body.
Ultrasound images of the left and right adrenal glands of a male Australian Cattle Dog. The left adrenal gland is 5.1mm thick and the right adrenal gland is 4.6mm thick. (Image credit: Dr. Gregory M. Kuhlman, DVM, DACVIM).
Ultrasound image of the left adrenal gland of an Addisonian female Great Dane. The adrenal gland is only is 2.7mm across. A healthy Great Dane adrenal gland should be around 7mm across. (Image credit: Dr. Gregory M. Kuhlman, DVM, DACVIM).
Your veterinarian may also perform a resting cortisol level test or adrenocorticotropic hormone stimulation test (ACTH) to confirm the diagnosis. An ACTH-stimulation test is considered the gold standard test for diagnosing Addison’s disease in dogs and cats. This test monitors the function of the adrenal glands after introducing the synthetic hormone, ACTH. This test involves injecting a hormone into a dog’s vein or muscle to test for adrenal gland activity and inflammation. A standard resting cortisol test is considerably less expensive than an ACTH stimulation test, but can only rule out Addison's, not confirm it.
Thus, it is vital to consult a veterinarian whenever your dog develops clinical signs of adrenal disease.
How is Addison's Disease in Pets Treated?
Addison's disease in dogs and cats is characterized by a deficiency of the adrenal gland's hormone cortisol. This results in a range of symptoms, including hyperpigea, lethargy, loss of appetite, weight loss, and increased cortisol levels in the blood. Treatment typically involves lifelong supplementation with daily oral steroids (such as prednisone) to replace cortisol, and monthly injections of desoxycorticosterone pivalate (also known as DOCP) to replace aldosterone.
Percorten and Zycortal are the brand names for desoxycorticosterone pivalate, which substitutes aldosterone and is used as a mineralocorticoid replacement. Depending on the needs of the individual dog, it must be injected every 4 weeks. It is essential to maintain the schedule of DOCP. To maintain your dog's health and happiness, you must have your veterinarian monitor their bloodwork and electrolyte levels on a regular basis. Addison's Disease can be managed if it is correctly diagnosed and treated.
Conclusion
There are a variety of reasons why a veterinarian might suspect a dog’s adrenal gland disease, including a loss of appetite, lethargy, or chronic gastrointestinal signs. If you’re worried about your pet’s health or notice any abnormalities with their behavior or appetite, contact your veterinarian for a thorough examination. Early detection and treatment of adrenal gland disease can help dogs live longer and healthier lives.
I've set up a GoFundMe campaign to help get Dekker tested for Addison's disease and possible GI issues that are keeping him from gaining weight. Dr. Greg is donating his appointment fee and part of the ultrasound fee. Please help us keep Dekker doing his wonderful therapy work.
Content reviewed and approved by Dr. Gregory M. Kuhlman, DVM, DACVIM (SAIM)
Dr. Kuhlman earned his Doctor of Veterinary Medicine degree from the University of Wisconsin. Following an internship in small animal medicine and surgery at the VCA Animal Emergency and Referral Center of Arizona, he completed a residency in internal medicine at Texas A&M University. Dr. Kuhlman enjoys all aspects of internal medicine, but he has a special interest in gastrointestinal, hepatobiliary, immune-mediated and infectious diseases. He has a passion for the treatment and management of the canine athlete and has been competing in and judging English springer spaniel field trials for over 20 years. He has a special interest in treating the canine athlete. On his days off, he can usually be found out training his dogs for AKC field trials, hunting upland game with his dogs, fly fishing or training for Ironman triathlons.
