Adrienne is a certified dog trainer, behavior consultant, former veterinarian assistant, and author of "Brain Training for Dogs."
Adrenal Gland Issues in Dogs
You may have never paid much attention to your dog's adrenal glands until they started to cause your dog trouble, making them feel under the weather and miserable.
In humans and dogs, the adrenal glands (also known as suprarenal glands because they sit on top of the kidneys) are responsible for many important functions essential for life. In particular, the adrenal glands produce mineralocorticoid aldosterone, which helps regulate blood pressure and electrolytes (salt, potassium, chloride), and glucocorticoid cortisol which is released during periods of stress and in response to episodes of low blood sugar.
When working well, your dog's adrenal glands ensure that everything is running smoothly. When the adrenal glands stop working as well as they should, too little adrenal gland hormone may be produced, leading to a medical condition known as Addison's disease, also known as hypoadrenocorticism.
The underlying reason why the adrenal glands may no longer work as they may stem from several factors:
- Autoimmune conditions (immune system mistakenly destroys some of its own adrenal tissues)
- Certain forms of cancer
- Abrupt discontinuation of steroids (hence, why it's so important weaning dogs off prednisone)
When the adrenal glands are damaged, a cascading chain of events may occur which may lead to several symptoms. These symptoms are often not readily recognized until they worsen over time and lead to what is known as an Addisonian crisis.
Addison's Disease: "The Great Pretender"
In the medical field, the term pathognomonic is used to describe a symptom that is specifically characteristic of a particular disease or condition. For instance, among humans, a sharp pain migrating to the right lower quadrant of the abdomen is often pathognomonic of appendicitis.
When it comes to Addison's disease, this disease is often far from producing symptoms that are pathognomonic. Addison's disease in humans and dogs is known for causing vague symptoms which may mimic the clinical signs associated with several other diseases, and is befittingly nicknamed "the great pretender."
Signs seen in dogs suffering from Addison's disease include:
- Weight loss
- Loss of appetite
- Intermittent vomiting and diarrhea
- Increased drinking and increased urination
- Episodes of weakness
Due to the vague symptoms and the fact that there are several more common disorders causing these symptoms, many vets fail to promptly diagnose Addison's disease in dogs assuming it's something else more common.
Dogs suffering from Addison's disease are often mistakenly diagnosed as suffering from inflammatory bowel disease, hemorrhagic gastroenteritis, pancreatitis, and acute or chronic kidney failure. This leads to dog owners spending lots of money on the wrong diagnostic tests and treatments while also losing precious time.
Owner Complaints With Percentage Based on Frequency
Loss of appetite
Signs of an Addisonian Crisis in Dogs
The symptoms of Addison's disease in dogs tend to be vague, waxing and waning, and progress slowly; they are often ignored until a stressful event takes place (such as boarding the dog in a kennel or moving) which will cause the disease to finally "come to a head."
At that breaking point, symptoms progress and become much worse leading to what is called an Addisonian crisis, or acute adrenal insufficiency. The signs of an Addisonian crisis tend to be prominent and often lead to an emergency vet visit or a trip to the emergency hospital. Typically, affected dogs will develop the following symptoms:
Loss of Appetite
Affected dogs will refuse to eat. This lack of appetite may take place hours or days prior to the time things progress and dog owners seek veterinary intervention.
Severe Vomiting and Diarrhea
Dogs suffering from an Addisonian crisis may develop severe abdominal pain along with vomiting and diarrhea. Dogs may vomit several times. Vomiting was witnessed in 68 percent of dog owners when their dogs developed a crisis, according to the above chart by Feldman and Nelson referenced above.
Diarrhea may be severe as well with dogs presenting with bright red, fresh blood in dog stool (hematochezia) or digested blood in the stool (melena), typically presenting as dark, tarry diarrhea.
Dehydration (Loss of Fluids)
When the dog's adrenal glands no longer work as they should, there will be a deficiency in aldosterone which, as we have seen previously, is responsible for keeping the dog's electrolytes in check.
With less aldosterone, therefore, the body excretes large amounts of sodium while potassium is retained. Affected dogs develop low sodium (hyponatremia) and high potassium (hyperkalemia). When too much sodium is lost and the dog vomits a lot and has diarrhea, the dog becomes dehydrated.
Dehydration may be recognized in dogs by lifting the skin over the neck and/or shoulders. In well-hydrated dogs, the skin will spring back quickly; in a dehydrated dog, it will be slow to go down or even worse, remains lifted. Dehydrated dogs may also develop sunken eyes.
Profound Muscle Weakness
Potassium plays a big role in the correct functioning of many muscles including skeletal muscles and the muscles of the heart. When potassium levels are impacted, this may lead to suppression of the electrical activity of the muscles which causes muscle cramps and muscle weakness.
Shaking is a symptom that is reported by some dog owners witnessing an Addisonian crisis in their dogs. The dog may shake as if feeling cold. Shaking can be triggered by low blood glucose levels.
Slow Heart Rate
A slow heart rate, medically known as bradycardia, is a symptom associated with an Addisonian crisis in dogs and it is due to the increased levels of potassium. Correct levels of potassium are important for maintaining a healthy heart rhythm. When the levels of potassium spike to a dangerous level, the electrical activity of the heart muscles can be severely impacted and may lead to a slow, weak or irregular pulse and even cardiac arrest.
Low Blood Pressure
Sodium plays the important role of helping maintain normal blood pressure. With lower sodium levels, dogs may develop low blood pressure due to renal sodium wasting and potassium retention.
Because good circulation allows oxygen-rich blood to reach a dog's tissues, when a dog develops low blood pressure, the gums may become pale which signals an emergency situation.
Low Blood Sugar
Cortisol plays a role in the regulation of blood sugar; in a dog suffering from Addison disease, the blood glucose may get too low. This can cause a cascading chain of events. In atypical hypoadrenocorticism, dogs may develop weakness and even seizures as a result of low glucose levels.
As a consequence of muscle weakness and potential dizziness which can take place during an adrenal crisis, dogs may stumble, stagger, and appear confused. Slow, uncoordinated movements may also result and further complications affecting the entire body may cause a dog to eventually collapse.
A drop in sodium levels in the body can lead to devastating hypovolemic shock. Hypovolemic shock means that the fluids in your dog's body drop decreasing the dog's overall blood volume.
Emergency Treatment for Addisonian Crisis in Dogs
If your dog ever develops symptoms of an Addisonian crisis, see your vet immediately. If left untreated, this condition can quickly turn lethal. Upon presentation, your vet will work on treating the hypovolemic shock and other signs of illness as soon as possible. The primary goal is treating the shock, and treatment typically takes precedence even before performing an ACTH stimulation test to confirm a diagnosis of underlying Addison's disease.
- Treatment primarily involves fluid therapy so to correct the dog's dehydration and low sodium and high potassium levels.
- Glucocorticoid therapy will include often the intravenous administration of dexamethasone sodium phosphate, and once the dog is stable, dog owners can administer steroids orally.
- Mineralocorticoid therapy may include fludrocortisone acetate (Florinef) may be administered. Another treatment option is desoxycorticosterone pivalate (DOCP), also known as Percorten, given subcutaneously or intramuscularly every 21 to 28 days.
- Routine checks of the dog's electrolyte levels should be scheduled to monitor any electrolyte changes that may suggest changes in therapy.
Therapy for Addison's disease in dogs is long-term, meaning for the rest of the dog's life. Although Addison's disease along with Addisonian crisis in dogs can be very scary, the good news is that once the dog is stabilized, the prognosis can be good to excellent. This also depends on the dog owner's compliance and education along with a willingness to follow the recommended therapy, explains veterinarian Dr. Marie E. Kerl a board-certified veterinarian specializing in internal medicine.
- Feldman EC and Nelson RW Canine and Feline Endocrinology and Reproduction. Philadelphia WB Saunders 1987
- Veterinary Partner: Addison's Disease (Hypoadrenocorticism)
- Textbook of Veterinary Internal Medicine, by Stephen J. Ettinger, DVM, DACVIM, Edward C.Feldman, DVM, DACVIM and Etienne Cote, DVM, DACVIM
© 2018 Adrienne Farricelli
Casey on June 11, 2018:
My 6 year old dog was in addisionain crisis on Friday and was put on fluids all weekend they we took him home with his meds but he hasn't eaten yet. I've been given him puppy milk water and force feeding him chicken. Is this common for him to still be off his food and still very weak
Adrienne Farricelli (author) on April 08, 2018:
Thanks Larry, with my dogs getting older, I need to be on the lookout for conditions as such. My dog is suffering from bouts of irritable bowel syndrome according to my vet, but I think Addison should be screened out with a baseline cortisol test just to be safe.
Larry W Fish from Raleigh on April 08, 2018:
Thanks for such an informative article, Adrienne. There is so much that a dog owner has to look out for that they have no idea about.I love reading about articles such as this to keep me informed.
What is Addison's disease?
The opposite of hyperadrenocorticism, or CushingвЂ™s disease, is called hypoadrenocorticism, or AddisonвЂ™s disease. In AddisonвЂ™s disease, the adrenal glands do not produce enough cortisol. In some cases, the affected dog has been treated with medications that suppress the production of cortisol, like some of the drugs used to treat CushingвЂ™s disease. In these cases, there is a clear reason for the cortisol deficiency, but in most cases, we just donвЂ™t know.
Dogs and Addison’s Disease
Certain diseases in pets are tricksters because they can mimic other health conditions. Addison’s disease mimics so well that it’s nicknamed ‘The Great Imitator” 6 .
Addison’s disease is another name for hypoadrenocorticism, which is the decreased production of hormones in the adrenal glands. It is less common than Cushing’s Disease (hyperadrenocorticism), which is the overproduction of adrenal hormones 7 .
The adrenal glands sit on top of the kidneys and have two major parts—the outer cortex and the inner medulla—that produce hormones. The cortex is affected by Addison’s disease. The cortex produces corticosteroids, which are categorized into glucocorticoids and mineralocorticoids 8 . Cortisol, aka the stress hormone, is a well-known glucocorticoid that controls the ‘fight or flight’ response. Aldosterone is a mineralocorticoid that regulates the body’s sodium and potassium levels.
In most cases of Addison’s disease, the cause remains unknown. Some potential causes are listed below:
- Autoimmune disorder that destroys adrenal tissue
- Overzealous treatment of Cushing’s disease
- Tumor that has spread to the adrenal glands
Addison’s disease occurs most commonly in dogs, mainly young, middle-aged female dogs. Certain dog breeds, such as standard poodles and Great Danes, are more susceptible to the disease 6 .
Clinical signs of Addison’s disease become apparent only when nearly all of the adrenal cortex has to be destroyed 8 . However, these clinical signs, which are listed below, are vague and resemble clinical signs of other diseases 7 :
- Vomiting and diarrhea
- Increased thirst and urination
- Weight loss
- Intermittent shaking
- Reduced appetite
These clinical signs can appear suddenly and wax & wane. They can worsen with stress because the adrenal glands aren’t producing enough cortisol to manage the stress.
Sometimes, the disease is severe enough to cause an Addisonian Crisis, which is a medical emergency 8 . During an Addisonian Crisis, a dog’s body goes into shock because it cannot respond adequately to stress. Immediate hospitalization and veterinary treatment are needed if this takes place.
Because Addison’s disease is ‘The Great Imitator,” clinical signs won’t be enough to make a diagnosis. A veterinarian will need to rely on the history provided by the pet parent, routine bloodwork, and a test called the ACTH Stimulation Test.
Bloodwork will show decreased sodium and increased potassium levels, which indicate an aldosterone deficiency.
The ACTH stimulation test is used to definitively diagnose Addison’s disease. To perform this test, a veterinarian will measure blood cortisol levels before and two hours after ACTH administration. ACTH is naturally produced by the pituitary gland and stimulates the adrenal glands to produce cortisol.
Cortisol levels that are low before ACTH stimulation and barely budge afterward indicate Addison’s disease 6 . A pet in an Addisonian Crisis receives immediate treatment performed before diagnostic testing.
Treatment and Prognosis
Severe cases of Addison’s disease require several treatments, including fluid therapy to restore normal sodium and potassium levels. Minimizing stress is another aspect of managing this disease.
Addison’s disease require lifelong replacement of glucocorticoids and mineralocorticoids in dogs. This treatment can either be done with an injectable medication every 3-4 weeks or a daily pill 7 .
Dogs with Addison’s disease do quite well and can live and happy lives, provided that their condition is well-managed 6 .
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6 Merck Veterinary Manual, Addison Disease.
7 Washington State University Pet Health Topics, Addison’s Disease.
8 Veterinary Partner, Addison’s Disease (Hypoadrenocorticism).
Can Addison's Disease be Prevented?
There is no way to prevent a dog from developing primary Addison's disease. Secondary Addison's may be avoidable by making sure your dog is carefully regulated while on any medications. Routine examinations can also help your veterinarian determine risk factors for Secondary Addison's.
Early detection can make it easier to manage Addison's disease. Follow your vet's advice for routine lab work. Mild abnormalities may allow your vet to discover Addison's before your dog actually gets sick. Preventing an Addisonian crisis is the best way to keep your dog safe.
Signs of an Addisonian Crisis in Dogs - pets
Addison’s disease (hypoadrenocorticism) is caused by a lower than normal production of hormones, such as cortisol, by the adrenal glands. The adrenals are small glands that are located near the kidneys. Adrenal hormones are necessary to control salt, sugar and water balance in the body.
Addison’s disease occurs less commonly than the opposite condition, Cushing’s disease (overproduction of cortisol) in dogs, and is rare in cats.
Addison’s disease occurs most commonly in young to middle-aged female dogs. The average age at diagnosis is about 4 years old. The signs of Addison’s disease may be severe and appear suddenly, or may occur intermittently and vary in severity. Signs may include weakness, depression, lack of appetite, vomiting, diarrhea, and occasionally increased thirst (polydipsia) and increased urine production (polyuria).
When a pet is stressed, their adrenal glands produce more cortisol, which helps them deal with the stress. Because dogs with Addison’s disease cannot make enough cortisol, they cannot deal with stress, so the signs may occur or worsen when stressed. What a dog finds stressful depends upon his/her temperament. For many dogs, any change in their day-to-day routine, such as being boarded or having house guests, is stressful and may precipitate or worsen signs of Addison’s disease.
On examination of dogs with Addison’s disease one may see depression, weakness, dehydration, weak pulses and sometimes a slow, irregular heart rate. Routine laboratory tests often show a low blood sodium and high blood potassium. Loss of water, in vomit and diarrhea, can lead to dehydration. Severe dehydration increases waste products in the blood (creatinine and blood urea nitrogen = BUN) that are normally eliminated by the kidneys. Addison’s disease can be confused with primary kidney disease. Some dogs with Addison’s disease have low blood sugar. See What Do Those Lab Tests Mean? for additional information about laboratory tests.
Sick dogs often show a pattern of changes in their white blood cells (WBCs) called a stress leukogram. This pattern of changes in the WBCs is caused by cortisol. The absence of a stress leukogram in a sick dog may be a clue to consider Addison’s disease. The urine is often dilute.
Increased blood potassium can cause life-threatening abnormalities in the heart rhythm. These abnormalities can cause the heart rate to be slow and irregular and can be seen on an electrocardiogram (ECG).
X-rays of dogs with Addison’s disease do not show any specific abnormalities. The heart may appear smaller than normal and rarely the esophagus (tube from mouth to stomach) can be enlarged.
The history, physical examination, and initial laboratory tests provide suspicion for Addison’s disease, but a more specific test, an ACTH challenge, should be performed to confirm the disease .
There are two stages of treatment for Addison’s disease in-hospital treatment and long term treatment. Very sick dogs with Addison’s disease require intravenous fluids, cortisol-like drugs and drugs to neutralize the effects of potassium on the heart.
Long-term treatment involves the administration of hormones in one of two forms either a daily pill or a shot that is given about every 25 days. Because dogs with Addison’s disease cannot produce more cortisol in response to stress, stress should be minimized whenever possible. It may be necessary to increase the amount of hormones given during periods of stress (e.g. boarding, surgery, travel, etc.).
With appropriate treatment for Addison’s disease, dogs can live a long and happy life.
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