I want to tell you about the eighteen months I spent explaining away Cooper’s symptoms.
He started drinking more water around age nine. “He’s always been a drinker,” I told myself. He developed a pot belly that made him look almost pregnant, while his limbs stayed lean. “He’s just aging into a different shape,” I said. His coat started thinning on his sides — symmetrically, in a way that should have been a red flag. “Labs shed. It’s fine.” He started having occasional accidents indoors overnight. “He’s getting older. Bladder control changes.”
All of those things, every single one of them, were textbook signs of Cushing’s disease. And I spent a year and a half seeing them and not connecting them, not because I was negligent, but because each symptom had a reasonable “just aging” explanation when viewed in isolation. It was only when his vet looked at the full picture at his annual exam that she said: “I want to run a test. I think this might be Cushing’s.”
She was right.
What Is Cushing’s Disease?
Cushing’s disease (hyperadrenocorticism) occurs when the body produces too much cortisol — the primary stress hormone. In dogs, this is almost always caused by one of two things: a small, usually benign tumor on the pituitary gland at the base of the brain (pituitary-dependent Cushing’s, the most common form, accounting for roughly 80–85% of cases), or a tumor on one of the adrenal glands (adrenal-dependent Cushing’s).
The pituitary tumor causes the pituitary to overstimulate the adrenal glands, which then produce excess cortisol continuously. The result is a body swimming in cortisol 24 hours a day — and cortisol does a lot of damage when it’s chronically elevated.
Cushing’s is most common in middle-aged to older dogs, typically appearing between ages 6 and 12. Certain breeds are predisposed: Poodles, Dachshunds, Boxers, Beagles, and yes — Labrador Retrievers.
The Symptoms: The Full List I Wish I’d Seen Sooner
Here’s the complete picture. If you’re seeing three or more of these together in a middle-aged or senior dog, Cushing’s should be on your radar:
- Excessive water consumption (polydipsia) — drinking significantly more than usual, often dramatically so
- Frequent urination (polyuria) — sometimes with indoor accidents in previously house-trained dogs
- Increased appetite — often described as sudden ravenous hunger in a dog that was previously a normal eater
- Pot belly / pendulous abdomen — from muscle weakness and fat redistribution; the dog may look pregnant or bloated even with weight loss elsewhere
- Hair loss (alopecia) — typically bilateral and symmetric, appearing on the flanks and abdomen; the skin beneath may appear thin and darkened
- Thin, fragile skin — bruises easily, heals slowly, may develop “blackheads” (comedones)
- Muscle weakness and exercise intolerance — gets tired faster, reluctant to climb stairs, may seem generally weak
- Panting — excessive panting, especially at rest, often at night
- Recurrent skin and urinary tract infections — cortisol suppresses the immune system, making infections more common and harder to resolve
- Lethargy — less interested in play, less energetic overall
Cooper had: excessive drinking, pot belly, hair thinning, muscle weakness, increased appetite, and recurrent skin infections. Six out of the ten. I had attributed each one separately to aging, diet, stress, the season.
Diagnosis: Why It Takes So Long
Cushing’s is notoriously difficult to diagnose. The symptoms mimic normal aging so closely that many vets — especially in non-specialist settings — don’t think to test for it until the presentation becomes obvious. And the diagnostic tests themselves are imperfect.
The two main screening tests are:
- LDDS (Low-Dose Dexamethasone Suppression) test: The dog receives a low dose of a synthetic steroid; in a normal dog, this suppresses cortisol production. In a Cushing’s dog, cortisol stays elevated. Blood is drawn at 4 and 8 hours. This is generally considered the most sensitive test for pituitary-dependent Cushing’s.
- UCCR (Urine Cortisol:Creatinine Ratio): A first-morning urine sample measured at home (less stress-influenced). A high ratio suggests Cushing’s but isn’t definitive — false positives occur with any condition causing stress.
If a dog tests positive on screening, an HDDS (high-dose dexamethasone) test or abdominal ultrasound is usually done to differentiate pituitary-dependent from adrenal-dependent Cushing’s, as the treatment differs.
Treatment
For pituitary-dependent Cushing’s — which Cooper had — the most common treatment is oral trilostane (brand name Vetoryl) or mitotane (brand name Lysodren). These medications reduce cortisol production. Trilostane has largely replaced mitotane as the preferred option because it has a more controlled mechanism of action, though it requires careful dose titration and regular monitoring with ACTH stimulation tests.
Cooper started on trilostane at age ten. The improvement within the first eight weeks was significant — his thirst reduced, his energy increased, his skin improved. We monitored his cortisol levels every three months. He did well on the medication until his cancer diagnosis complicated everything.
I’ll be honest with you: I have anger and grief mixed together when I think about those eighteen months I spent dismissing his symptoms. Would earlier diagnosis have changed his outcome? The Cushing’s was likely not directly related to his cancer. But he spent a year and a half feeling worse than he should have, with symptoms that could have been managed, because I kept saying “he’s just getting old.”
What I Want You to Take Away
If your dog is middle-aged to older and you’re seeing a cluster of symptoms — especially the combination of increased thirst/urination + pot belly + hair loss — bring it up with your vet specifically. Don’t wait for it to be raised at the next annual wellness exam. Say: “I’ve read about Cushing’s disease and I think we should test for it.”
You might be wrong. The test might come back normal. That’s fine — that’s what tests are for. But if you’re right, earlier treatment means a better quality of life for your dog and fewer months of cortisol-driven damage to their body.
With Birch, I track her water intake, her weight, and her coat condition in a simple notebook. It sounds excessive. I’d rather be excessive than spend another year dismissing what I’m seeing.
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