고양이 요관 결석·요관 폐색 증상과 원인, 진단·치료와 관리 포인트 총정리

Cat Suddenly Unable to Urinate — Emergency Signs of Ureteral Obstruction and How to Respond

KidneyDiseasesMeongsiljang Veterinary Advisory Board

Feline ureteral calculi and ureteral obstruction are serious conditions that can severely impair kidney function due to blockage of the urinary tract. Early detection and appropriate treatment are key to improving survival rates.

What Are Feline Ureteral Stones and Ureteral Obstruction?

Diagram of a cat’s urinary tract blocked by urethral stones

Feline ureteral stones and ureteral obstruction are conditions in which the ureter, the tube connecting the kidney to the bladder, is blocked by a stone, impairing normal urine flow. Ureteral obstruction can also result from hardened blood clots, strictures, tumors, or external compression, not just stones. If this condition persists, the renal pelvis dilates, causing the kidney to swell (hydronephrosis), and in severe cases, it can lead to kidney damage or kidney failure. - Ureteral obstruction: A condition in which the ureter is blocked, preventing urine from flowing into the bladder, requiring prompt evaluation and treatment. - Causes of stone formation: When urine becomes supersaturated with minerals, crystals form. In cats, calcium oxalate and struvite stones are the most common. - Risk of kidney damage: The extent of damage depends on whether the obstruction is unilateral or bilateral, partial or complete, its duration, and the presence of underlying kidney disease. - Importance of early detection: If only one ureter is blocked, early symptoms may be subtle, so it is important to visit the clinic promptly if you suspect an issue.

Main Causes and Pathogenesis

Feline ureteral stones form when urine becomes supersaturated with minerals, leading to crystal formation. The most common types of stones in cats are calcium oxalate and struvite. - Insufficient water intake: When cats don’t drink enough water, their urine becomes concentrated, increasing the risk of stone formation. That’s why encouraging adequate water consumption is so important. - Dietary factors: To help prevent calcium oxalate stones, it’s recommended to avoid foods that are excessively high in protein, calcium, oxalate, or sodium. - Urinary tract infections: Bacterial infections are associated with struvite crystal formation and can contribute to stone development. - Other causes of ureteral obstruction: Ureteral blockages can result not only from stones but also from hardened blood clots, strictures, inflammatory debris, or tumors. - Mechanism of ureteral obstruction: When stones or other materials block the ureter, urine cannot drain properly, causing the renal pelvis to dilate and the kidneys to swell, which can lead to pain and kidney damage.

The microscopic structure of feline urinary stones

Main Symptoms and Signs

Feline ureteral stones and ureteral obstruction may not always present with obvious symptoms, but if you notice any of the following signs, a veterinary visit is necessary.

Changes in urination: Your cat may visit the litter box frequently, strain to urinate, pass only small amounts of urine, or show blood in the urine.

Signs of abdominal pain: Your cat may show discomfort, vocalize, or be reluctant to move when its abdomen is touched.

Vomiting and loss of appetite: As kidney function declines, waste products (uremic toxins) can build up, leading to vomiting or reduced food intake.

Lethargy and signs of shock: In severe cases, your cat may appear weak and limp, with abnormal breathing or heart rate. If both ureters are blocked or the urethra is obstructed, hyperkalemia can develop, creating a life-threatening emergency.

Decreased urine output or anuria: If only one ureter is blocked, the unaffected kidney may still produce urine, so the total volume may not drop significantly. However, if both ureters are blocked or the urethra is obstructed, urine output may be minimal or absent.

Behavioral signs of cats suffering from urethral obstruction

Emergency Situations Requiring Immediate Veterinary Visit

If both ureters are blocked or the urethra is obstructed, resulting in little to no urine output, and your pet shows signs of severe pain or shock—such as lethargy, weakness, or abnormal breathing and heart rate—seek veterinary care immediately. The extent of kidney damage caused by obstruction depends on the scope of the blockage (unilateral or bilateral, partial or complete), its duration, and whether there is pre-existing kidney disease, so prompt treatment is crucial.

Accurate Diagnostic Methods

Diagnosing feline ureteral stones and ureteral obstruction requires a combination of tests, as relying on a single method can lead to missed diagnoses. Therefore, it is recommended to use both ultrasound and radiography together. - Ultrasound: This is useful for diagnosing obstruction by identifying hydronephrosis (dilation of the renal pelvis) and ureteral dilation. However, stones may be missed if there is no ureteral dilation. - Radiography (Abdominal X-ray): This helps confirm the presence of stones, but radiolucent lesions, such as organized blood clots, may not be clearly visible. - Urinalysis and Culture: These tests check for hematuria (blood in the urine) and signs of inflammation or infection. For patients with azotemia, urine culture and antibiotic susceptibility testing are recommended. - Blood Tests: These assess kidney function indicators (creatinine and BUN) to evaluate the extent of renal damage. - Additional Imaging: If necessary, further examinations such as intravenous urography or retrograde pyelography may be considered.

A cat undergoing ultrasound to diagnose ureteral stones

Treatment Methods and Step-by-Step Management

Treatment focuses on relieving pressure in the obstructed ureter and restoring urine flow. - Medical stabilization: Intravenous fluids correct dehydration and uremia, while pain relievers and diuretics help increase urine production and excretion. - Ureteral stent placement: A double-J stent or similar device is inserted to bypass the blockage and allow urine to flow. - Subcutaneous ureteral bypass (SUB): An artificial bypass tube is surgically implanted to divert urine from the kidney to the bladder. - Surgical removal (e.g., ureteroneocystostomy): Surgery may be required to directly remove stones or reimplant the ureter into the bladder. - Follow-up dietary management: Long-term management with a prescription diet tailored to the stone composition is essential. Medical treatment alone does not always resolve the issue, so surgical intervention is often necessary.

A scene of a cat undergoing ureteral stent insertion surgery

Home Care and Recovery Points

Consistent aftercare is key to preventing recurrence. - Increase water intake: Place water bowls in multiple locations and incorporate wet (canned) food to encourage your pet to drink more. - Use prescription diets as directed: Consistently feed the special therapeutic diet, such as one formulated to prevent calcium oxalate stones, as recommended by your veterinarian. - Monitor urination: Keep a daily record of the frequency and volume of urination, as well as any signs of pain. - Schedule regular check-ups: Follow your veterinarian’s recommended schedule for urine tests and ultrasounds to check for recurrence. Regular imaging is especially helpful for senior cats, who are more prone to stones. - Adhere to medication instructions: Ensure your pet takes all prescribed medications exactly as directed.

An environment where cats drink plenty of water

Preventing Recurrence and Breed-Specific Precautions

Urinary tract stones and urethral obstructions are conditions that tend to recur. If your cat has experienced these issues before, it’s a good idea to work with your veterinarian to develop a long-term plan that includes increasing water intake and dietary management. Stones are also not uncommon in senior cats, so we recommend regular urine tests and ultrasound exams at intervals recommended by your vet.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

What causes urinary tract stones in cats?

When urine becomes oversaturated with minerals, crystals can form. In cats, calcium oxalate and struvite stones are the most common. Factors such as insufficient water intake, diet, and urinary tract infections can contribute to their development. In particular, the risk increases when cats don't drink enough water, leading to concentrated urine.

How long can a pet survive with a ureteral obstruction?

The rate of tissue damage depends on whether the obstruction is unilateral or bilateral, partial or complete, how long it has persisted, and whether there is any underlying kidney disease. Because there’s no fixed timeframe and earlier intervention yields better outcomes, you should visit a veterinary clinic immediately if you suspect an issue.

If a stone forms, can it be treated without surgery?

Internal medicine treatments, such as intravenous fluids, pain relievers, and diuretics, can help increase urine output, but a single approach doesn’t always resolve the issue. In cases of urethral obstruction, interventions like stent placement, subcutaneous ureteral bypass (SUB), or surgery are often necessary, with the specific treatment determined by the veterinarian’s assessment.

What kind of diet should I feed to prevent recurrence?

It’s important to consistently feed your pet a special diet recommended by your veterinarian. A calcium oxalate prevention diet is formulated to avoid excessive protein, calcium, oxalate, and sodium while encouraging increased water intake, which helps reduce the risk of stone formation.

Can a cat experience a recurrence of urethral obstruction after having had one?

Since this condition tends to recur, it’s important to work with your veterinarian to develop a long-term management plan. Regular check-ups, along with ensuring adequate hydration and dietary adjustments, are key.

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References

[1] Boyd LM, Langston C, Thompson K, et al. Survival in cats with naturally occurring chronic kidney disease (2000-2002). J Vet Intern Med. 2008;22:1111–1117.

[2] Specht AJ, Kruger JM, Fitzgerlad SD, et al. Light microscopic features of chronic feline idiopathic cystitis (abstract). J Vet Intern Med. 2003;17(3):436.

[3] Adams LG, Williams Jr. JC, McAteer JA, et al. In vitro evaluation of canine and feline calcium oxalate urolith fragility via shock wave lithotripsy. Am J Vet Res. 2005;66(9):1651–1654.