Struvite Crystals in Cats: Symptoms, Causes, Diagnosis and Treatment

Struvite crystals are microscopic mineral crystals that can form in a cat's urine. They are made from magnesium, ammonium and phosphate, and it is not unusual for a small amount of these crystals to be present in a cat's urine.

Causes for concern are when the crystals become excessive, clump together and form bladder stones that block the urinary tract. Struvite crystals are among the most common types of urinary crystals or stones seen in cats, alongside calcium oxalate.

In this guide, we look at struvite crystals in cats, how they can contribute to stone formation, and when to be concerned.

What Do Struvite Crystals Mean for a Cat?

Struvite crystals can sometimes irritate the bladder and urinary tract. They are a common contributing factor to feline lower urinary tract disease (FLUTD). This is actually an umbrella term for conditions affecting the bladder and urethra.

It's important to note that urinary signs are not always caused by struvite. Other common causes of these issues include:

• Stress-related cystitis
• Infection
• Calcium oxalate stones
• Other related conditions

Veterinary diagnosis of urinary problems is essential because the correct treatment depends on the type of crystal or stone in question. Struvite stones may be dissolvable through a special diet, but calcium oxalate stones usually cannot be dealt with this way.

Many cats recover well with the right veterinary care, diet and monitoring. The key is noticing the problem and getting it diagnosed.

How Struvite Crystals Affect Cat Urine

Struvite crystals are more likely to form when urine conditions cause mineral precipitation. Here are the key urinary factors:

• Urine pH: Struvite tends to form more readily in alkaline urine.
• Urine concentration: Concentrated urine increases mineral build-up.
• Urine volume: Low urine volume means minerals sit in the bladder for longer.
• Hydration: Cats that do not drink much or eat mostly dry food may produce more concentrated urine.

When you take your cat to the vet, they may assess urine pH, urine specific gravity, the presence of crystals, and any other abnormal presences in urine.

You may have heard that dry food "causes" struvite. This is not entirely accurate — it may contribute to more concentrated urine in some cats if their total water intake is low.

Is There a Way to Monitor Urine at Home?

It can be difficult to keep an eye on urine quality in the home, but we have something that can help. Litter Sense cat litter is an innovative silica crystal-based litter that can give you an early warning sign that something isn't right with your cat's urine.

Thanks to its smart design, our cat litter changes colour when it comes into contact with irregular cat urine. The presence of blood or an abnormal pH level triggers the colour change, giving you the first indication that something might not be as it should be.

This is not a diagnosis of anything in particular, but it can help you get your cat assessed and catch issues relating to urine at the earliest possible opportunity, maximising the likelihood of a good outcome.

Symptoms of Struvite Crystals or Bladder Stones in Cats

If your cat has struvite crystals in their urine, there are various symptoms that could tell you. Litter Sense cat litter provides you with a clear sign, but here are some behavioural symptoms to look out for:

• Frequent trips to the litter tray
• Passing only small amounts of urine
• Straining to wee
• Crying or showing discomfort when urinating
• Excessive licking around the genitals
• Restlessness or hiding
• Reduced appetite or lethargy
• Urinating outside the litter tray

It's important to note that these things can also be signs of something else. You might also want to look out for visible blood in the urine or strong-smelling, cloudy urine. These are all signs that you should book an appointment with your vet as quickly as possible.

Some cats will show very few obvious symptoms until the problem becomes more severe, which is why Litter Sense can be so helpful. Other possible conditions associated with these symptoms include cystitis, urinary tract infection, stress-related urinary disease and other bladder conditions.

Sudden litter tray changes are often among the first signs of urinary discomfort.

When Is It an Emergency?

If you spot your cat straining and/or crying but passing very little or no urine, that cat needs urgent veterinary attention. Urinary blockage is particularly dangerous for male cats because they have a narrower urethra.

A blocked bladder can quickly become life-threatening for cats, so it should be treated as an emergency. Look for the following emergency signs alongside the ones listed previously:

• Repeatedly trying to wee with little or nothing coming out
• Crying in the litter tray
• A swollen or painful belly
• Vomiting
• Collapse
• Severe lethargy
• Refusing food

Don't ignore these signs — act fast to get treatment for your cat.

What Causes Struvite Crystals in Cats?

Struvite formation is usually linked to urine chemistry rather than one single cause. Here are the most common contributing factors to struvite crystals in cats:

• Alkaline urine
• Concentrated urine
• Low water intake
• Diet composition
• Infrequent urination
• Stress and environmental changes
• Being overweight or inactive
• Some urinary tract infections (though bacterial UTIs are less common in younger cats than in dogs)

Indoor cats may be at higher risk of urinary problems if they have issues like limited enrichment or stress from other cats. Indoor cats are sometimes more likely to drink too little. As the owner, you should create an environment that encourages dilute urine, regular urination and a healthy urinary pH.

How Are Struvite Crystals Diagnosed?

A proper diagnosis of this problem should be made by a vet — it isn't something you can diagnose by symptoms alone. A vet will usually start with a physical examination, checking pain, bladder size and overall condition.

From here, diagnostic methods might include:

• Urinalysis: Checking pH, concentration, blood, crystals, proteins and signs of infection.
• Microscopy: Identifying the type and appearance of crystals.
• Urine culture: Used if infection is suspected.
• Blood tests: Checking kidney function, hydration and general health.
• X-rays or ultrasound: Used to look for bladder stones or obstruction.
• Stone analysis: If stones are surgically removed or passed.

The type of crystals involved must be identified as different stones need different types of treatment. The wrong diet or supplement could actually make some urinary issues worse. Struvite crystals in a urine sample don't necessarily prove that stones are present.

How Are Struvite Crystals and Stones Treated?

Once the presence of struvite is confirmed, the treatment depends on whether there are only crystals or larger stones, infection, pain, inflammation or blockage. A prescription diet aimed at dissolving struvite stones is a common treatment option, alongside increased water intake.

Hydration may be improved through wet food or mixed feeding where suitable. In the meantime, a cat may be prescribed pain relief or anti-inflammatory medication. Antibiotics are only relevant if bacterial infection is confirmed. If stones can't be dissolved, they may need to be removed through surgery.

If the cat's urinary tract is blocked, emergency catheterisation may be needed. Struvite stones tend to be more diet-responsive than some other stone types. However, owners shouldn't try to acidify urine or change to a prescription diet without guidance from their vet.

Can Diet Dissolve Struvite Stones?

Some prescription urinary diets can help dissolve struvite stones by encouraging the right urine pH and controlling magnesium, phosphorus and other minerals. They might also increase thirst or urine volume, depending on the formula.

These diets are therapeutic — it isn't a case of simply switching to ordinary "urinary health" foods. A vet may recommend feeding the diet exclusively for a set period, which may mean some discipline and extra effort on your part to avoid mixing in treats or supplements.

Follow-up urine checks or imaging may be needed to confirm improvement. Diet can be powerful, but only when the diagnosis is correct.

How to Help Prevent Struvite Crystals Coming Back

If you want to prevent a recurrence of struvite crystals in your cat, you will need to focus on hydration, diet, stress reduction and ongoing monitoring. Here are some practical prevention points that should help:

• Feed the vet-recommended urinary diet if prescribed
• Encourage wet food where appropriate
• Provide multiple fresh water bowls around the home
• Try a cat water fountain
• Keep water away from food bowls and litter trays if the cat prefers it
• Keep litter trays clean and accessible
• Encourage regular play and movement
• Help overweight cats lose weight gradually under vet guidance
• Reduce stress from other pets, house moves, loud noises or poor litter tray placement

As part of your monitoring, keep an eye on litter tray habits. Watch for things like blood, straining or repeated visits, and always attend follow-up vet checks. Litter Sense cat litter will provide you with a visual aid to see if there is anything abnormal about your cat's urine.

Remember, cats often hide discomfort. Small changes in toileting behaviour are important.

Frequently Asked Questions About Struvite Crystals in Cats

Are struvite crystals in cats dangerous?

Not always, but they can become dangerous if they form stones or contribute to a blockage.

Can struvite crystals go away?

They usually improve with the correct diet, hydration and treatment, but the cause needs veterinary assessment.

Can struvite crystals cause blood in cat urine?

Yes, crystals or stones may irritate the bladder, but blood can also be caused by cystitis, infection or other urinary problems.

Are male cats more at risk?

Male cats are more at risk of dangerous urinary blockage because their urethra is narrower.

Should I change my cat's food if they have struvite crystals?

Only after speaking to a vet. Different urinary problems need different dietary management, so it is important to get it right.