Health & Medical

He kept collapsing and nobody knew why. Not daily, not even weekly, but every so often the labrador would stand up from a rest, take two steps, and fold at the knees, then recover in minutes and act as if nothing had happened. Three vets, two blood panels, and a year of "probably just old age" later, an internist ran the test that named it: Addison's disease, the great imitator, because it looks like everything and confirms as almost nothing until you know to look.

Addison's, or hypoadrenocorticism, is failure of the adrenal glands to make enough of two hormones, cortisol and aldosterone. Cortisol is the stress hormone everyone knows; aldosterone controls salt and potassium balance, and without it the body cannot hold sodium or shed potassium. The result is a dog who intermittently wilts, vomits, goes off food, drinks oddly, and sometimes collapses, then bounces back, because the hormone shortage fluctuates rather than staying consistently low.

The classic crisis is the dangerous version. A dog in an "Addisonian crisis" is shocky: weak, cold, vomiting, with low blood pressure and dangerous electrolyte swings, and it can look like poisoning or a gut blockage. That acute form gets diagnosed fast because the dog is obviously dying. The slow, waxing-and-waning form is the one that evades everyone for months, because the dog is fine between episodes and the routine tests look boring.

Finding it, and living with it

The diagnosis is one specific test, an ACTH stimulation test, that measures the adrenal response directly, and it is the test a general vet may not reach for because the dog in front of them looks normal that day. If a young to middle-aged dog has vague, recurring episodes of lethargy, gut upset, and weakness that resolve on their own, and especially if routine bloods show a low sodium-to-potassium ratio, this is the test to ask for. I wish the first vet had been handed that sentence a year earlier.

Treatment is lifelong but manageable, which is the good news after the long confusion. The cornerstone is a monthly injection, given by the vet, that replaces the missing hormones in a slow-release form, and most dogs do beautifully on it. Some need additional oral steroids during stress, illness, or surgery, because the body cannot ramp cortisol up the way a healthy one does. Owners learn to dose up before a boarding stay or an operation, because that is when an Addisonian dog is most at risk.

The change in our neighbour's dog was immediate and strange to watch. The dog who had been a ghost of himself on bad days became, on the right medication, the bouncy labrador he had been at two. The collapses stopped. The vomiting stopped. The "old age" at five years old evaporated. It was not old age. It was a missing hormone, and a single monthly shot gave it back.

There are two forms worth knowing. The typical form, missing both cortisol and aldosterone, shows the full electrolyte disturbance and the dramatic crises. The atypical form, missing mainly cortisol, presents more subtly and is the one most often missed for months, because the dog is simply off, intermittently, without the scary chemistry. Both are managed with replacement hormones, but the atypical dog may need only steroid cover and not the monthly mineral injection, which is why the specific diagnosis matters for the rest of the dog's life.

Monitoring is light but necessary. Most dogs on the monthly injection do well for years with little intervention, but any illness, injury, or stressor means they need extra steroid, because a healthy dog ramps cortisol up for such moments and an Addisonian one cannot. Owners learn to dose before boarding, before surgery, during vomiting bugs, and to carry a note for vets who might otherwise miss the condition in an emergency. The monthly injection is given by the practice, which adds a small recurring cost, and the oral steroids are cheap. Compared with the cost of repeated crisis visits, which can run into thousands for a single bad episode, the maintenance is trivial. The change in our neighbour's dog was immediate once correctly treated: the collapses stopped, the appetite returned, and the "old age" at five evaporated, which is the part that still astonishes, that a missing hormone had mimicked the end of a life and a single shot gave it back.

The takeaway for any owner of a dog with mysterious, on-again-off-again weakness is to mention Addison's by name and ask for the ACTH stim test, especially if episodes follow stress or if the bloods show that sodium-potassium hint. It is rare enough that vets screen for it late, but treatable enough that finding it early changes everything. A dog who keeps collapsing and recovers may simply be waiting for someone to test the one thing that explains all of it.