Often called The Great Pretender, Addison’s disease is an uncommon but potentially life-threatening condition.
Addison’s, or hypoadrenocorticism, is a hormonal disease affecting dogs.
It causes a reduction in the steroid hormones, which affects the whole body in various ways.
It is most commonly seen in middle aged females, causing very vague signs which come and go.
Treatment is based on replacing the missing hormones with monthly injections and daily tablets.
What is Addison’s Disease?
Addison’s, or hypoadrenocorticism, is a disease which arises when the body (specifically the adrenal gland) stops producing normal amounts of the steroid hormones called cortisol and aldosterone. These hormones are needed by all the cells within the body in order to remain healthy. When a dog doesn’t produce enough of these hormones, they can become unwell and if these hormone levels become very low, it can be a life-threatening emergency.
What are the Adrenal Glands?
The Adrenal glands are two glands which are found at the top of each kidney. They produce a number of vital substances which are secreted into the bloodstream and travel around the body. These substances are known as hormones and they help regulate many important bodily functions, without which, your dog would not be able to survive. The most important hormones produced by the adrenal glands are the steroid hormones cortisol and aldosterone.
These two hormones are needed by every cell in your dog’s body in order to remain healthy. Addison’s disease occurs when there are too little of these steroid hormones being produced.
Cortisol has many functions, from helping your dog respond to stress and stimulating its appetite to regulating the body’s immune system which fights off infections.
Aldosterone is the hormone responsible for maintaining the body’s salt levels – sodium and potassium. Having too many or too little of these salts can have serious consequences for the body.
What Causes Addison’s?
There are a number of causes for Addison’s but the most common cause is the body’s own immune system accidentally attacking the adrenal glands. This leads to damage to the glands so they do not produce normal levels of cortisol and aldosterone. This is known as immune-mediated disease.
Other, less common conditions which can damage the adrenal glands and lead to Addison’s include:
Prescription drug side effects
Whilst Addison’s can be seen in any dog and at any age, it tends to be seen more frequently in:
Young - Middle aged, females
Standard Poodles, West Highland White Terriers, Great Danes, Bearded Collies, Nova Scotia Duck Tolling Retrievers, Portuguese Water Dogs
As cortisol and aldosterone have such a wide-ranging effect on bodily functions, the symptoms we see can be very varied.
Low energy and weakness
Lack of appetite (anorexia)
The symptoms are often vague, come and go and vary in intensity. Sometimes the only symptom is just that your dog is “not quite right”.
In severe cases, some dogs develop ‘shock-like’ symptoms and collapse. These signs come on suddenly and can become an emergency. This is known as an ‘Addisonian Crisis’.
How is Addison’s Disease diagnosed?
As the signs of Addison’s are so vague, further tests are needed to reach a diagnosis.
A general health blood test is usually performed first to check liver and kidney function and electrolyte level. If these initial tests are suspicious of Addison’s, more specific blood tests are then required to test the function of the adrenal gland and the production of the steroid hormones. Urine tests, an ultrasound scan and possibly and ECG are also often used to help in the diagnosis.
What treatments are there for Addison’s Disease?
Unfortunately, there is no cure for Addison’s. Treatment is lifelong and based on hormone replacement in the form of a monthly injection (to replace the hormone aldosterone) given by your vet and daily steroids (to replace cortisol) which are given at home.
What outlook can I expect for my dog?
It can take time to reach the correct dosage for your dog when starting treatment, so be prepared for multiple trips to the vet initially. The dosage required can change over time and may need to be adjusted, especially during times of stress.
If your dog responds well to treatment and does not have any other underlying diseases which may complicate the treatment, then the overall outlook can be good to excellent.
Problems can arise if your dog develops other conditions eg. Diabetes which can make treatment complicated, or if your dog does not respond to treatment.
If your dog has recently been diagnosed with Addison’s and you would like more time to discuss the condition, the friendly vets at MyDogDoc would be happy to see you!