Understanding Addison's Disease in Dogs: Symptoms and Treatment

Addison's disease, or hypoadrenocorticism, is a rare but serious condition in dogs where the adrenal glands fail to produce enough essential steroid hormones, mainly cortisol and aldosterone. These hormones regulate vital functions such as stress response and electrolyte balance. Early signs can be subtle, making the disease difficult to spot until an Addisonian Crisis—a life-threatening emergency—occurs.

What Causes Addison's Disease in Dogs?

Addison's disease typically results from damage to the adrenal glands. The most common cause is an autoimmune response where the dog's immune system mistakenly attacks the glands, reducing hormone production. Other causes include tumours, physical injury, or prolonged use of steroid medications that suppress natural hormone production.

This condition can affect any dog breed, but some breeds such as Standard Poodles, West Highland White Terriers, and Great Danes have a predisposition. It is most frequently diagnosed in young to middle-aged dogs, particularly females aged 4 to 7 years.

Recognising the Signs: Symptoms to Watch For

The early symptoms of Addison's disease can be vague and intermittent, making them easy to miss. Common signs include:

• Lethargy and weakness
• Occasional vomiting and diarrhoea
• Loss of appetite and weight loss
• Muscle tremors and shaking
• Increased thirst and urination

These signs may improve temporarily, causing owners to delay veterinary advice. However, without treatment, dogs risk developing an Addisonian Crisis characterised by severe vomiting, diarrhoea, dehydration, collapse, shock, and potentially death.

Types of Addison's Disease

There are three recognised forms of Addison's:

• Primary Addison's: Damage directly to the adrenal glands, most often autoimmune.
• Secondary Addison's: Caused by pituitary gland issues leading to insufficient stimulation of the adrenals.
• Iatrogenic Addison's: Due to abrupt withdrawal or prolonged use of steroid medications suppressing adrenal function.

Diagnosis: How Your Vet Confirms Addison's Disease

Diagnosing Addison's is complex, as symptoms overlap with other illnesses. Blood tests check electrolyte levels—particularly sodium and potassium—and evaluate white cell counts. A sodium to potassium ratio below 25:1 can indicate Addison's.

The definitive diagnosis is made using the ACTH Stimulation Test. Blood samples are taken before and after administering synthetic ACTH. Normally, ACTH stimulates cortisol production from adrenal glands. If cortisol levels remain low after stimulation, Addison's disease is confirmed.

Treating Addison's Disease: What to Expect

While Addison's is incurable, current treatments effectively manage the condition and allow affected dogs to live well with proper care and monitoring.

Emergency Management of Addisonian Crisis

If your dog suffers an Addisonian Crisis, immediate veterinary care is critical. Treatment includes intravenous fluids to correct dehydration and electrolyte imbalances and intravenous corticosteroids such as dexamethasone to replace missing cortisol rapidly.

Long-Term Hormone Replacement Therapy

Chronic management involves replacing deficient hormones through:

• Tablet therapy: Fludrocortisone tablets to replace aldosterone and daily steroids like prednisolone for cortisol.
• Injection therapy: Desoxycorticosterone pivalate (DOCP) injections every 3 to 6 weeks, which have become a preferred method for mineralocorticoid replacement due to effective control and reduced side effects.

Regular blood testing is essential to adjust medication doses and monitor your dog's health. Stress minimisation, a consistent medication routine, and routine veterinary check-ups are key.

FAQs about Addison's Disease in Dogs

What is an Addisonian Crisis?

Quick Answer: An Addisonian Crisis is a sudden, severe worsening of Addison's disease causing collapse, shock, and potentially death without emergency treatment.

This crisis happens when hormone levels drop critically low, leading to dangerous dehydration, electrolyte imbalances, and cardiovascular collapse. Immediate veterinary intervention with fluids and corticosteroids can save your dog's life.

Can any dog breed get Addison's disease?

Quick Answer: Yes, Addison's disease can affect any breed, although certain breeds are more prone.

Breeds with higher risk include Standard Poodles, West Highland White Terriers, Portuguese Water Dogs, Great Danes, and Saint Bernards. Responsible breeding practices are important to reduce inherited risks.

What should I do if I suspect my dog has Addison's disease?

Quick Answer: If your dog shows symptoms like unexplained vomiting, lethargy, or shaking, seek veterinary advice promptly.

Early diagnosis and treatment improve outcomes. Your vet can perform diagnostic tests including the ACTH stimulation test to confirm Addison's and recommend appropriate therapy.

Can dogs with Addison's live normal lives?

Quick Answer: Yes, with lifelong treatment and regular vet monitoring, dogs with Addison's disease can lead happy, active lives.

Owner education on recognising signs of crisis and adherence to medication schedules are crucial. Many dogs enjoy years of good quality life following diagnosis and treatment.

Conclusion

Addison's disease in dogs is a complex but manageable endocrine disorder. Awareness of symptoms, timely diagnosis, and committed long-term hormone replacement can significantly improve your dog's quality of life. Never delay veterinary attention if you notice concerning signs, especially because an Addisonian Crisis can be fatal without emergency care.

For those considering getting a dog, always seek puppies from reputable breeders who prioritise health and genetic screening to minimise risk of inherited diseases like Addison's.