Scientifically known as hypoadrenocorticism, Addison’s disease has serious consequences for dogs as most of the pooches that are not diagnosed in due time or receive proper treatment are not expected to have normal lifespans. Put simply, Addison’s disease is what occurs when the dog’s adrenal glands cannot produce the hormones they are in charge of.
The most important hormones secreted by these glands are by far steroids — cortisol and aldosterone, in particular. They play a large role in regulating your dog’s body systems and internal organs. Without them, the dog’s body eventually deteriorates, which means that your canine companion can suffer major complications and could even die.
But what are the causes of this disease? How can it be treated? Are some dogs more predisposed to it than others? Let’s find out the answer to all of these questions.
In the majority of cases, the causes of Addison’s disease remain unknown and while many veterinarians suspect that it is a result of an autoimmune process, it can also be caused by the actual destruction of the adrenal gland, hemorrhage, a metastatic tumor, as well as a variety of medications such as mitotane or trilostane.
While any dog can develop Addison’s disease, whether she is a purebred or mixed breed, there are some breeds that are apparently more predisposed to having it. These are West Highland White Terriers, Bearded Collies, Portuguese Water Dogs, Standard Poodles, Nova Scotia Duck Tolling Retrievers, as well as Soft Coated Wheaten Terriers.
However, this medical condition can occur regardless of gender, age, or the dog’s breed.
The reason why this disease can be so difficult to diagnose, especially in its progressing stage, is that it has a wide range of symptoms associated with it. Dogs that are affected by it can have anything from poor appetite to bouts of gastroenteritis, an inability to respond correctly to stress, as well as a generally slow loss of body condition.
When the production of aldosterone is decreased, it has a significant impact on your dog’s body. It leads to a variety of changes in serum levels of chloride, sodium, and potassium, and these all affect the dog’s kidneys. That’s how a dog with Addison’s disease can end up suffering from kidney issues and even pathologies of the heart and circulatory system.
Cortisol, another major steroid hormone secreted by the adrenal glands, plays an important part in most tissues of your pet’s body. It effectively regulates the metabolism, glucose production, blood pressure, and it also influences the breakdown of proteins and fat, and it stimulates the formation of red blood cells. Cortisol is also in charge of suppressing inflammation, and it is capable of counteracting stress.
A significant reduction in the production of both of these hormones causes symptoms such as lethargy, depression, weight loss, anorexia, diarrhea and/or vomting, alopecia, bloody stools, increased thirst and increased urination, shaking, dehydration, a weak pulse, a painful abdomen, hypoglycemia, irregular heart rate, or hyperpigmentation of the skin. Low temperature can also be seen in some dogs.
Diagnosing Addison’s disease in dogs
Once you bring your dog in for a checkup, your vet will perform a complete physical exam. Diagnostic tests are usually required to identify the cause of the illness, especially since the clinical signs are so diverse and can characterize a variety of medical conditions. Unfortunately, most cases of Addison’s disease are diagnosed during an Addisonian crisis where the condition reaches an acute stage, and the dogs experience symptoms such as shock or collapse.
Once the dog is brought in, some of the tests that could be performed are the following:
- Chemistry tests for evaluating liver, kidney, and pancreatic function
- Antibody tests to determine whether your pet was exposed to infectious diseases
- A complete blood cell count
- Electrolyte tests
- Urine tests to screen for urinary tract infections and the kidney’s ability to concentrate urine
- An ECG to screen for a potential abnormal heart rhythm
- A thyroid test to rule out whether or not the thyroid gland is malfunctioning and producing too little thyroid hormone
- An ACTH-stimulation test to determine the level of cortisol in your pet’s blood
Resolving the crisis is the most important course of action as it is an acute medical emergency. In such an event, your dog will be hospitalized, and he or she will undergo intensive therapy so as to best manage the symptoms of the crisis.
Once your canine companion is out of danger, and the diagnosis is clear, the vet will prescribe a replacement hormone medication which will help with dealing with the deficiency. More than one medication is typically prescribed – such as a daily steroid (prednisone) and a monthly injection of a mineralocorticoid. Annual or biannual blood work will be necessary for the future to make sure that the medication is working.
Your dog will need a lifelong replacement of both aldosterone and cortisol. Therefore, Addison’s disease is not curable. In some situations that cause stress (such as traveling, boarding, or surgery), your dog might receive increased doses of cortisol.
While the prognosis for the majority of dogs diagnosed with this disease is good to excellent, once the diagnosis is made, the medication regimen is chosen and stabilizes the pet’s hormone levels for the remainder of their lives.
Can Addison’s disease in dogs be prevented?
Since the causes of this medical condition are still unclear, it is not usually preventable. The exception is a medication-induced crisis. For example, if your dog is prescribed medications for Cushing’s disease (such as trilostane or mitotane), an accidental overdose can lead to an Addisonian crisis. What you can do, in this case, is to monitor your dog’s medication with care and keep the drugs out of your pet’s reach.