Urine Crystals and Bladder Stones in Cats: Causes, Symptoms & Treatment

Optimizing hydration and diet helps ease discomfort and prevent blockages.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 10, 2025

Optimizing hydration and diet helps ease discomfort and prevent blockages.

Urine Crystals and Bladder Stones in Cats: Complete Guide

Cats are known for their unique and sometimes enigmatic behaviors, but when it comes to their health, issues like urine crystals and bladder stones can pose serious risks if left untreated. This article covers everything cat owners need to know about these urinary problems, including their causes, symptoms, diagnosis, treatments, and ongoing care. Understanding these conditions empowers caretakers to protect their feline companions from discomfort and potential emergencies.

What Are Urine Crystals and Bladder Stones in Cats?

Urine crystals (crystalluria) and bladder stones (uroliths, cystic calculi) are related but distinct urinary tract problems in cats:

Urine crystals are microscopic mineral precipitates that can sometimes be found in normal cat urine. At higher concentrations or under the right conditions, these crystals can fuse together and form stones.
Bladder stones are rock-like formations composed of minerals and organic material, ranging in size from tiny grains like sand to gravel and even larger masses. Stones may be solitary or multiple and can cause irritation, inflammation, and even obstruction within the bladder or urethra.

How Do Crystals Become Stones?

While low levels of crystals may not cause immediate harm, they can clump together over time, especially in the presence of dehydration, concentrated urine, or dietary imbalance. These agglomerates develop into larger stones capable of causing significant local damage or urinary blockage.

Symptoms of Urine Crystals and Bladder Stones in Cats

Cats may hide their discomfort, so it is crucial for owners to recognize early warning signs and act promptly. Common symptoms include:

Small, frequent urinations
Straining or taking a long time to urinate
Urinating outside the litterbox (sometimes in sinks, bathtubs, or laundry)
Blood in the urine (hematuria)
Painful urination â may vocalize, cry, or show signs of restlessness
Excessive licking of the genital area
Chronic or recurrent urinary tract infections
Urine spraying or passing urine in unusual places

Signs of a urinary emergency (especially in male cats):

Multiple unsuccessful attempts to urinate, with little or no urine produced
Straining with almost no urine output
Restlessness, crying out in pain, or hiding
Distended, painful abdomen

Note: Bladder stones often produce symptoms lasting longer than those of crystals alone. Blockages are much more common and life-threatening in male cats due to their longer, narrower urethra. A complete blockage is a medical emergency requiring immediate veterinary intervention.

Causes of Urine Crystals and Bladder Stones

Several interrelated factors contribute to the formation of crystals and stones in cats:

Diet: Diets high in certain minerals (magnesium, phosphorus, calcium, chloride, fiber) or those that promote highly concentrated urine are major contributors. Dry food, in particular, increases the risk by providing less moisture and promoting chronic dehydration.
Dehydration: Cats evolved to obtain most of their water from prey, so many cats drinking from bowls consume less water than needed, resulting in concentrated urine which increases the risk of crystal and stone formation.
Urine pH: High pH (alkaline urine) favors the formation of struvite crystals/stones, while low pH (acidic urine) favors calcium oxalate types.
Infection: Some bladder stones, especially struvite, can form in response to urinary tract infections that alter urine pH and composition. However, many cats develop stones without infection.
Breed Predisposition: Some purebred cats, such as Siamese, show genetic susceptibility to certain types of stones.
Age & Sex: Middle-aged to older cats (5-14 years) have a higher incidence of calcium oxalate stones. Male cats are at greater risk for dangerous urethral blockages.
Underlying Health Conditions: Liver shunts, chronic kidney disease, and medications can disrupt mineral balance in urine.

Types of Crystals and Stones

Type	Mineral Composition	Common Risk Factors	Usual Age Range
Struvite	Magnesium ammonium phosphate	Alkaline urine, high mineral diet, sometimes infection	Any age; younger to middle-aged cats
Calcium Oxalate	Calcium and oxalate	Acidic urine, high calcium, chronic kidney disease	5â14 years
Other Types (rare)	Urate, cystine, mixed	Breed, genetic, metabolic disease	Varies

Struvite and calcium oxalate stones account for most feline urinary stones, with struvite being the most common.

Diagnosis of Crystals and Stones in Cats

Diagnosis involves a combination of clinical evaluation, laboratory tests, and imaging:

Physical Exam: Palpation of the bladder may reveal thickening, discomfort, or even detect large stones.
Urinalysis: Reveals presence of crystals, blood, infection indicators, and urine pH.
Urine Culture: Determines whether a urinary infection exists and identifies bacteria if present.
Imaging: X-rays (radiographs) and ultrasound are used to visualize stones, determine their size, number, and assess if there is obstruction or bladder wall damage.
Blood Tests: Assess overall health, kidney function, electrolyte imbalances caused by urinary blockage.

In male cats with frequent straining and little or no urine produced, rapid diagnosis is essential to avoid complications such as bladder rupture or life-threatening electrolyte imbalances.

Treatment of Crystals and Bladder Stones

Treatment depends on the type and severity of the condition, the type of stones present, and the presence of obstruction or infection.

Medical Dissolution

Dietary Management: Special prescription diets can alter urine pH and reduce the minerals involved in stone formation, dissolving some types of stones (especially struvite). There are no over-the-counter diets proven effective for this purpose.
Increased Fluid Intake: Feeding canned or wet food increases water consumption and helps dilute the urine, reducing the risk of crystal and stone formation.
Treatment of Underlying Conditions: Controlling infections, metabolic disease, or correcting diets helps resolve and prevent further issues.

Note: Calcium oxalate stones cannot be dissolved by dietary means and will require surgical or other physical removal.

Surgical and Non-Surgical Procedures

Cystotomy: The surgical removal of bladder stones through an abdominal incision. This is required for stones not responsive to medical dissolution or causing severe symptoms or obstruction.
Urethral Catheterization: In the case of obstruction (blockage), immediate placement of a urinary catheter under anesthesia is necessary to restore urine flow.
Non-Surgical Removal: Under specific circumstances, some small stones may be flushed out using a technique called urohydropropulsion; however, this only applies to carefully selected cases.

Prevention and Long-term Management

Preventing recurrence after treatment is critical for lifelong urinary health in cats:

Canned Moist Food: Feeding a diet high in water content is one of the best ways to limit crystal and stone formation in predisposed cats. Wet foods dilute the urine and decrease mineral concentrations.
Urinary Prescription Diets: Cats with a history of stones require long-term dietary management. Therapeutic diets are designed to maintain urine pH, reduce mineral excess, and prevent crystal formation.
Fresh Water: Ensure multiple sources of clean, fresh water are always available to encourage drinking.
Regular Vet Exams: Monitor for early recurrence with routine urine and blood testing, especially in cats with a previous history.
Reduce Stress: Environmental stress can contribute to urinary issues. Provide plenty of litterboxes, a calm environment, and stress reduction strategies.

Discuss your cat’s specific prevention plan with your veterinarian, especially for breeds or individuals known to be at high risk.

Frequently Asked Questions (FAQs)

Q: Are urine crystals in cats always dangerous?

A: Not all crystals in cat urine are a problem, but in high concentrations or when accompanied by other risk factors, they can lead to stone formation, irritation, or urinary blockage. Always consult your vet if crystals are found, especially if symptoms are present.

Q: Can I treat my catâs bladder stones at home?

A: Home remedies are not recommended, as improper management can lead to complications or life-threatening obstructions. Always seek veterinary care to determine the type of crystal or stone and proper treatment.

Q: How can I tell if my male cat has a urinary blockage?

A: Signs include repeated visits to the litterbox with little or no urine produced, straining, crying, restlessness, and a swollen, painful abdomen. This is a medical emergencyâseek immediate veterinary attention.

Q: What is the difference between a urinary tract infection and bladder stones?

A: Both can cause similar symptoms, such as straining and blood in the urine. However, bladder stones are physical obstructions or irritants, while infections are caused by bacteria. Sometimes, stones and infections occur together.

Q: Are certain cat breeds more susceptible to urinary stones?

A: Yes, some breeds, such as Siamese, are predisposed to specific types of stones due to genetic factors.

Key Takeaways

Urine crystals and bladder stones in cats are common and potentially serious urinary tract conditions.
Symptoms include frequent urination, straining, accidents outside the litterbox, and blood in the urine.
High-mineral dry diets, dehydration, genetic predisposition, and urinary pH changes are leading causes.
Diagnosis relies on urinalysis, imaging, and laboratory work to determine type and extent of condition.
Treatment involves a combination of prescription diets, increased water intake, medication, and sometimes surgery.
Prevention relies heavily on appropriate diet, ample water intake, and ongoing veterinary monitoring.

When to Seek Emergency Veterinary Care

If you ever notice your cat straining to urinate, producing little or no urine, crying out, or suddenly hiding and acting withdrawn, assume an emergency until proven otherwise. Immediate veterinary attention can be life-saving, particularly for male cats prone to life-threatening blockages.

References

Author

Sneha TeteBeauty & Lifestyle Writer

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to thebridalbox, crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living.

Read full bio of Sneha Tete