FR
ENWhat is Addison's disease?
The adrenal glands, located above each kidney, produce two hormones essential to survival. In Addison's disease, these glands stop working correctly and hormone production becomes insufficient. The result: a serious mineral imbalance and an inability to respond to physical stress.
Manages stress, supports metabolism and the immune system. Without cortisol, the dog cannot cope with physical challenges, even minor ones.
Regulates the sodium/potassium balance in the blood. Without aldosterone, electrolytes become dangerously imbalanced and the heart, kidneys, and muscles suffer quickly.
Two forms of the disease
Combined deficiency of both aldosterone AND cortisol. The most common form, with electrolyte imbalance (low sodium, high potassium) on top of metabolic disruption.
Cortisol deficiency only, without electrolyte abnormalities. Often harder to detect because routine bloodwork can appear normal. Treated with prednisone alone.
Known causes
Autoimmune
The immune system attacks and destroys the adrenal cortex. This is the most common cause.
Cushing's over-treatment
Excessive dosing of Trilostane or Mitotane can permanently suppress adrenal function.
Other causes
Trauma, infections, adrenal tumors, pituitary disorders, or unknown causes (idiopathic).
Breed predisposition
Labrador Retrievers, Great Danes, Portuguese Water Dogs, and Standard Poodles are more commonly affected.
Diagnosis is often delayed by months, sometimes over a year, because symptoms disappear between episodes. That is why it is called the "great pretender": the dog seems fine, then crashes again.
Signs and symptoms
Addison's symptoms are typically intermittent: the dog is fine, then declines, then recovers, sometimes spontaneously. This "roller coaster" pattern is exactly what makes the diagnosis so difficult and so often delayed.
Early stage
- •Variable energy (good days, bad days)
- •Intermittent diarrhea
- •Intermittent vomiting
- •Sporadic weight loss
- •Clingy behavior, seeking comfort
Intermediate stage
- •Increased thirst and urination
- •Shivering or trembling episodes
- •Frequent appetite fluctuations
- •Occasional collapse
- •Intermittent anorexia
Advanced stage
- •Severe muscle weakness
- •Irregular heart rhythm
- •Inability to maintain normal weight
- •Sudden crisis with little warning
- •Coma
Between episodes, the dog may appear completely normal. This does not mean they are well: it means their remaining hormonal reserves are just barely compensating, until the next trigger.
The Addisonian crisis
An Addisonian crisis occurs when a stressful event (illness, anesthesia, travel, sudden routine change) overwhelms the body's ability to compensate. Without cortisol or aldosterone, the dog goes into shock.
- Severe weakness, inability to stand
- Generalized trembling
- Collapse
- Seizures
- Extreme lethargy, no response
- Hypersalivation, uncontrollable vomiting and diarrhea
- Coma
Stress dosing: what you need to know
If your dog is already diagnosed and must undergo surgery, anesthesia, or is going through a severe illness, your vet will temporarily increase the glucocorticoid dose. This protocol, called a "stress dose," is essential to prevent a crisis. Discuss it with your veterinarian before any planned procedure.
How is the diagnosis made?
Addison's disease mimics many other conditions: gastroenteritis, kidney failure, hypothyroidism, neurological disorders. Diagnosis is often reached after several visits, when the veterinarian notices the characteristic intermittent pattern or suggestive electrolyte abnormalities.
Clinical suspicion
The vet notes the pattern of intermittent symptoms, episodes of weakness and vomiting, and bloodwork showing hyponatremia (low sodium) and hyperkalemia (high potassium). A Na/K ratio below 27 is strongly suggestive of Addison's.
ACTH stimulation test
This is the confirmatory test. The vet injects ACTH (the hormone that stimulates the adrenal glands) and then measures the cortisol response. If the adrenal glands do not respond, the diagnosis is confirmed. This test is simple, reliable, and can be performed even during a crisis.
Additional workup
Complete bloodwork (CBC, biochemistry, electrolytes), urinalysis, and sometimes abdominal ultrasound to visualize the adrenal glands (often small in autoimmune Addison's) or investigate an underlying cause.
Identifying the form
If electrolytes are normal despite an insufficient ACTH response, the vet diagnoses the atypical form. Follow-up and treatment differ slightly: prednisone alone, without a mineralocorticoid.
Treatment and management
Treatment replaces what the adrenal glands can no longer produce. Once the right dose is found, most dogs stabilize very quickly and return to normal quality of life. The treatment is lifelong but simple to manage day to day.
Percorten-V® (DOCP)
Desoxycorticosterone pivalate, injected every 3 to 4 weeks. Replaces aldosterone and restores the Na/K balance. Can be administered at home after training. Blood monitoring at each injection to adjust the dose.
Daily prednisone
Given at a low dose each day to replace the missing cortisol. The dose is adjusted to the dog's condition and temporarily increased during stressful situations (illness, surgery, travel).
Florinef® (fludrocortisone)
An oral option combining mineralocorticoid and glucocorticoid effects. An alternative when the injectable protocol is not suitable. Less common than DOCP + prednisone, but effective for some dogs.
Long-term monitoring
- Blood tests every 3 to 6 months (electrolytes, kidney function, cortisol)
- DOCP dose adjusted based on the Na/K ratio measured before each injection
- Prompt visit if digestive symptoms, unusual fatigue, or behavioral changes
- Stress dose protocol prepared in advance with the vet for planned situations
What to expect long-term?
Among chronic canine diseases, Addison's has one of the best prognoses once diagnosed. The disease does not shorten life if well managed.
Unlike many chronic diseases, well-managed Addison's is not a degenerative condition. The dog does not deteriorate over time; they remain stable as long as treatment is properly maintained.
Home management
Keep a health log
Essential actions
- Follow the DOCP injection schedule strictly (mark it on a calendar)
- Never miss the daily prednisone without veterinary guidance
- Refill medications in advance, never run out
- Designate one person responsible for giving medications to avoid missed doses
- Set up a stress-dose protocol with your vet for any planned stressful situations
- Minimize stress: avoid sudden routine changes, loud environments, anxiety-inducing situations
- Consult promptly if: repeated vomiting, marked lethargy, sudden loss of appetite
- Always inform any emergency or after-hours vet that your dog has Addison's disease
- Keep a copy of the treatment protocol in your dog's bag and as a photo on your phone
Never do
- Stop or change medication doses without consulting your vet
- Ignore unusual fatigue or a digestive episode assuming it will pass on its own
- Give extra prednisone without a pre-established protocol from your vet
- Forget to mention Addison's before any anesthesia or surgical procedure
Frequently asked questions
Why did the diagnosis take so long?
My dog will need medication for life. Is it really necessary?
What is a stress dose and how do I set it up?
Can my dog exercise, travel, and live normally?
How much does long-term treatment cost?
What if my dog vomits their prednisone?
This guide is provided for informational and educational purposes only. It does not constitute veterinary medical advice and is not a substitute for a consultation with a qualified veterinarian. Every animal is unique and their health must be evaluated individually. If you have concerns about your pet's health, contact our clinic or consult a veterinarian promptly.