When Stones Become Catastrophic: Severe Urolithiasis and Acute Kidney Failure
Dr. Geoff Carullo, DVM, FPCCP, DPCVSCA
- Articles
- 4 min read
Urolithiasis in cats is something most small-animal veterinarians encounter regularly. But every once in a while, a case appears that reminds us how devastating this condition can become when obstruction is severe, delayed, or complicated by infection.
This case involved one of the largest uroliths I have personally diagnosed. The stone was so radiographically obvious that it could not be ignored. More concerning, however, was its location. The urolith lodged at the trigone of the urinary bladder, effectively obstructing urinary outflow. The result was acute urinary blockage, pus-laden urine, gross hematuria, and rapid progression to acute kidney failure.
This is urolithiasis at its worst.
In cats, urinary obstruction is already a medical emergency. When the obstruction occurs near the trigone, it compromises both ureteral outflow and bladder emptying. Pressure rapidly builds within the urinary system, leading to:
In this case, the presence of pus and blood suggested a complicated obstruction, likely involving secondary bacterial cystitis on top of the mechanical blockage.
Yes. And in some practices, it feels more common than ever.
While we have improved diets, diagnostics, and owner awareness, we are also seeing:
All of these contribute to an environment where crystals can form, aggregate, and eventually develop into stones.
Although stone composition varies, the most common types seen in cats include:
Large stones like the one in this case are often calcium oxalate, which explains why they can grow silently over time until obstruction suddenly occurs.
Urolithiasis is rarely caused by one factor alone. It is usually multifactorial.
Key contributors include:
In obstructive cases complicated by infection, stagnant urine allows bacteria to flourish, producing pus and worsening inflammation.
Once urine cannot exit the bladder, pressure transmits backward to the kidneys. Glomerular filtration rate drops rapidly. Toxins accumulate. Within hours to days, the cat can progress from stable to critical.
This is why urinary obstruction is not a “wait and see” condition. It is a race against time.
Prevention is far more effective than emergency intervention.
Key preventive strategies include:
For cats with a history of stones, long-term dietary and lifestyle management is non-negotiable.
This case is a reminder that urolithiasis is not always benign. Stones can grow silently. Obstruction can occur suddenly. And once kidney failure develops, the stakes are life-and-death.
Radiographs don’t just show stones. They show missed time.
Early detection, owner education, and preventive care remain our strongest weapons against cases like this.
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