Calcium Tartrate Tetrahydrate Stones in Dogs: What Every Pet Parent and Vet Needs to Know

Introduction: New Insights into Canine Urolithiasis

A recent study from the Journal of Veterinary Internal Medicine (May–June 2025) reports a newly recognized form of urinary stone, calcium tartrate tetrahydrate (CTT), found in dogs. This emerging discovery highlights important links between diet, supplements, and stone formation. It also underscores the need for heightened vigilance among pet owners and veterinary teams alike.

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What Are CTT Stones, and Why the Buzz?

CTT uroliths have only recently been documented in canine patients, marking an important expansion in our understanding of stone types in dogs. Unlike the more familiar calcium oxalate or struvite stones, CTT stones appear to have a distinct source: tartaric acid salts, particularly choline bitartrate.

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Who Is Affected?

The study examined 63 dogs with confirmed CTT stones. Key characteristics:

• 84% were male (53 out of 63 dogs)
• 76% were small purebred breeds (48 out of 63)
  These demographics suggest that small male purebreds may be at highest risk

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Root Cause: Diet, Supplements & Choline Bitartrate

In a subset of 33 cases where dietary and supplement histories were available, 76% (25 dogs) had exposure to ingredients containing tartaric acid Strikingly, among those 25 cases, 96% (24 dogs) had consumed choline bitartrate specifically.
Choline bitartrate, commonly added to pet diets and supplements for its cognitive and metabolic benefits, appears to be the most likely dietary source of this new stone type.

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Pathophysiology Made Clear

Here’s a simplified breakdown of how CTT stones may develop:

1. Ingestion of choline bitartrate (a tartaric acid salt) via food, vitamins, or medications.
2. Renal excretion of tartrate anions—possibly combining with calcium in the urinary tract.
3. Precipitation of calcium tartrate tetrahydrate (CTT) crystals, which aggregate into uroliths under favorable urinary conditions.
4. Stone formation, especially in susceptible dogs (male, small-breed), leading to urinary issues such as pain, obstruction, or recurrent UTIs.

This mechanism reminds us of other chemically induced uroliths seen historically in rodents and other animals, but this is among the first documented in canines associated with choline bitartrate.

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Implications & Recommendations

For Pet Owners:

• Awareness is key: Check ingredient lists (both pet food and supplements) for choline bitartrate.
• Ask your vet if your dog has a history of stones or recurrent UTIs, especially if they’re on supplements or medications that include choline bitartrate.
• Watch for symptoms: Hesitation to urinate, frequent attempts, bloody urine, or pain.

For Veterinarians:

• Include CTT in your differential when analyzing uroliths, especially in small male breeds.
• Thoroughly review your patient’s diet, supplements, and medications for choline bitartrate or other tartaric acid derivatives.
• Educate clients on the potential risks of supplements—even commonly recommended ones.
• Promote stone analysis: Always send uroliths for compositional testing—now more than ever, new stone types can emerge!

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Conclusion: Knowledge Is Prevention

The identification of CTT stones in dogs and the clear association with choline bitartrate underscores the evolving nature of veterinary science. Both pet owners and veterinary professionals must stay informed about emerging risks, even from widely used supplements. As this knowledge spreads, we can better detect, manage, and prevent this newly recognized form of urolithiasis.

Let’s work together to ensure our furry friends stay healthy…one awareness post at a time.