Addison's Disease in Dogs: Symptoms, Diagnosis & Treatment

Addison's disease, when diagnosed and treated correctly, means your four-legged friend can lead an active and normal life much like any other dog, even with the condition. But what exactly is this disease? Also known as adrenal insufficiency or hypoadrenocorticism, Addison's disease presents with symptoms commonly seen in other ailments, making it challenging for vets to diagnose.

Vets often have to use a process of elimination before diagnosing Addison's disease. Once your dog is on the correct medication, they can enjoy a full, normal life, though lifelong medication is required.

What Causes Addison's Disease?

Your dog has an adrenal gland above each kidney, made up of two parts: the cortex (outer layer) and the medulla (inner layer). The cortex normally produces corticosteroid hormones, mainly cortisol and aldosterone, vital for many body functions. Addison's disease affects the cortex, reducing hormone production, while the medulla usually remains unaffected.

Types of Addison's Disease

There are three types: primary, secondary, and atypical Addison's disease:

• Primary and atypical Addison's disease: Usually caused by damage to the adrenal glands due to an autoimmune reaction where the immune system attacks them.
• Secondary Addison's disease: Results from pituitary gland failure to stimulate the adrenal glands with ACTH (adrenocorticotropic hormone).

It is crucial to understand which type your dog has, as treatment approaches may vary.

Why is Addison's Disease Hard to Diagnose?

Symptoms are often vague and overlap with many other health problems. Early signs include listlessness, seeming depressed, or 'off colour'. Loss of appetite in a normally healthy eater is a red flag requiring prompt veterinary evaluation.

Recognising Symptoms of Addison's Disease

Alongside behavioural changes, common physical symptoms include vomiting, diarrhoea, muscle weakness, hind quarter pain, shivering, and tremors. Symptoms may disappear and return intermittently, complicating diagnosis. Over months or years, adrenal function worsens, potentially leading to an Addisonian crisis.

What Happens in an Addisonian Crisis?

An Addisonian crisis is a medical emergency where potassium levels rise, causing heart rhythm disturbances (arrhythmia) and dangerously low blood pressure. Kidney function deteriorates, leading to renal failure. Prompt intravenous fluid therapy is critical and often successful in recovery. Diagnosis is often confirmed during treatment for this crisis.

How Do Vets Confirm Addison's Disease?

Vets monitor electrolyte levels, especially sodium and potassium, and the ratio between them. While changes often indicate Addison's, secondary and atypical forms may not affect electrolytes. The definitive ACTH stimulation test involves measuring cortisol before and after injection with ACTH to assess adrenal gland function.

Mention any glucocorticoids your dog is taking (like prednisone) to your vet before testing, as this can affect results. Dexamethasone does not interfere with the test.

Treatment Options for Addison's Disease

Treatment typically includes replacing mineralocorticoids (to maintain electrolyte balance) administered orally or by injection. Glucocorticoids like hydrocortisone replace cortisol deficiencies. Secondary or atypical Addison's generally require only glucocorticoids, as electrolytes remain normal.

Can Dogs Live Normal Lives with Addison's Disease?

With appropriate lifelong medication and close monitoring, dogs with Addison's can enjoy happy, active lives. Owners become skilled at recognising early signs of change, helping vets adjust treatment promptly. Your pet can continue to enjoy all the activities and love you share.

Responsible pet ownership includes regular veterinary check-ups and medication adherence to manage this condition effectively.

For those considering adding a dog to their family, always seek reputable breeders or look into adoption options to make responsible choices in pet acquisition.