Hypoadrenocorticism, or adrenal insufficiency, more commonly known as Addison’s Disease, isn’t common in dogs, but it can occur. Addison’s disease in dogs can be a difficult condition to diagnose and treat because the symptoms are so similar to other conditions and they’re also very easy to go unnoticed, and at first they might not seem that serious. It’s for this reason that it’s very important that dog owners keep an eye on their pet, have the capability to see when something is “off” or different about their pet, and take their dog to the vet at the first sign of sickness. Doing so can assure your dog of a long, happy life.
What is Addison’s Disease?
Addison’s disease is a condition that affects the adrenal glands, which are located on top of the kidneys. The cortex is the outer area of these glands and is responsible for secreting corticosteroid hormones known as cortisol and aldosterone. When there is either too much or too little of these hormones being secreted, Addison’s disease can develop and become a serious health problem if it’s not taken care of quickly.
There are three main forms of Addison’s disease that exist. These are primary, secondary, and atypical. When the adrenal glands have been damaged, this is known as either primary or atypical Addison’s disease, while secondary Addison’s disease is caused by the pituitary gland failing to stimulate the adrenals with a certain type of hormone known as adrenocorticotropic. If a vet suspects the presence of Addison’s disease, the first thing they will do is try to determine the type of Addison’s disease the dog suffers from so that proper treatment can be administered.
Causes of Addison’s Disease
There are three main causes of Addison’s disease. These are:
- A deficiency in the adrenocorticotropic hormone
- Metastatic tumors (tumors that have spread from another area of the body)
- A withdrawal of the glucocorticoid hormone which occurs over a long period of time
In addition to the symptoms of Addison’s disease being vague, they can also come and go over time, making it even more difficult to diagnose. One of the most telling symptoms, and unfortunately also one of the scariest, is when the adrenal glands become so damaged that the dog has an acute episode of Addisonian crisis. When this happens potassium levels will increase, which will in turn disrupt the normal functions of the heart and can even cause arrhythmia. Over time the kidneys can also start to fail.
Diagnosing Addison’s Disease
When you take your dog into the vet suspecting Addison’s disease, the first thing they will likely test is the dog’s electrolyte levels, mainly for sodium and potassium. A dog that has Addison’s disease will likely have high sodium levels while their potassium levels will be very low.
Testing for electrolyte levels is important, but these levels alone will not definitively diagnose Addison’s disease. Sometimes, especially if the dog is suffering from secondary or atypical Addison’s, the electrolyte levels won’t show any difference in their levels at all.
In order to be certain that it’s Addison’s disease your dog is suffering from, the vet will need to perform an ACTH stimulation or response test. This test will determine how capable the adrenal glands are of producing the corticosteroid hormone cortisol. With this test, one blood sample will be taken first to see where the dog’s cortisol levels currently sit. Then the dog will be injected with a pituitary hormone that will send the signal to the adrenal glands to produce cortisol. This injection needs an hour to fully work and once that time is over, another blood sample will be given to once again test the cortisol levels to determine if they have increased at all. When the cortisol levels haven’t changed or still remain relatively low, a diagnosis of Addison’s disease will then be conclusive.
While these blood tests are typically enough to diagnose Addison’s disease, there are steps that will be completed beforehand to try and make it as comfortable and non-invasive as possible for your dog. These steps will include a complete medical history as well as the symptoms that your dog has been experiencing, so it’s important to write them down as they occur so you don’t forget any. Urine tests and a physical exam will most likely also be done before the cortisol test. If your vet is still unsure of the diagnosis, x-rays and ultrasounds may also be done to verify whether the adrenal glands have enlarged or shrunk from their normal size.
Treatment of Addison’s Disease
The treatment of Addison’s disease will depend on how greatly your pet has been affected. If the condition has become severe, hospitalization and intensive therapy may be initially required. If the dog is severely dehydrated, fluids given intravenously may also be part of the treatment.
Once the most severe symptoms have been addressed, a regular and consistent treatment will need to be administered to ensure that the dog doesn’t suffer anymore and that the symptoms subside. The only way to ensure that happens is to treat the underlying condition, the deficiency of hormones in the adrenal glands. In order to do this, hormone replacement therapy will be required, and these will need to be administered also via IV for the remainder of their lives.
Hormone replacement therapy will be very intensive at first. For the first four weeks the dog will need to be taken to the vet to have their hormone levels regularly checked. Only this way can the vet properly record, maintain, and adjust the amount of hormones your dog needs. Once this initial therapy is complete and the correct hormone dosage has been determined, injections can usually be given monthly or every three weeks. During hormone replacement therapy, both during initial and on-going treatment, the electrolyte levels will also be regularly checked to ensure that they too are at adequate levels and that the disease is being maintained properly.
Addison’s disease in dogs can be a very serious condition, but it’s definitely not a fatal one. Though it takes great vigilance and compliance on the part of the owner, dogs who suffer from Addison’s disease can still continue on to live a very happy and healthy life, just as they did before the presence of Addison’s disease.