Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

What Are Struvite Crystals in Cats? Our Vet Explains Causes & Treatments

Urine sediment showing Struvite crystals

If you notice any changes in your cat’s urination habits, this could be a sign of an issue with the urinary tract and could be struvite crystals. This problem could be resolved with a vet-developed diet or result in surgery. Let’s look at what you should know about preventing and treating struvite crystals.

divider 3 paws

What Are Struvite Crystals?

Struvite crystals form within the urinary tract. They are a combination of phosphate, magnesium, and ammonium. While you might find low numbers of struvite crystals in normal urine, they can also indicate or lead to bladder problems, such as bladder stones.

What Are the Signs of Struvite Crystals in Cats?

Struvite crystals can be an incidental finding on a urinalysis, but they can also be associated with urinary tract infections. As such, signs of struvite crystals include:

  • Increased frequency of urination (pollakiuria)
  • Blood in urine (hematuria)
  • Straining to urinate (stranguria)
  • Inappropriate urination
  • Crying, especially when trying to urinate

Some pets with urinary tract infections can be lethargic or have a decreased appetite. So, it’s always worth it for your veterinarian to check a urinalysis if your cat is acting “off.”

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

Struvite crystals can be associated with urinary blockages, particularly in male cats. They are at a higher risk for blockages because their urethra is longer and narrower, so it’s easier for crystal clumps, mucus, and even stones to block the passage of urine.

A urinary obstruction can be life-threatening. There are a few consequences of a urinary blockage. First, the bladder can distend and rupture. Cats can develop kidney failure. Electrolyte imbalances are possible, and if your cat can’t urinate, their potassium levels may increase. If they get too high, cardiac arrhythmias are possible, particularly bradycardia or low heart rate.

black and white cat peeing outdoor
Image Credit: nanniezwawa, Shutterstock

divider 3 paws

What Are the Causes of Struvite Crystals in Cats?

In dogs, struvite crystals are commonly associated with urinary tract infections. We don’t see that as commonly in cats, but it’s still possible. In these cases, bacteria produce urease, which decreases the pH of the urine and makes it more likely for struvite crystals to form.

Struvite crystals may form if the urine is very concentrated. Cats that don’t drink as much water tend to have more concentrated urine and may have a higher risk of struvite formation. Your cat’s diet may cause a more alkaline or basic urine pH, which might cause crystals. Your cat is also at a higher risk if their diet produces more magnesium or phosphorus in their urine.

Sick sad cat lying on the bed
Image Credit: Zhuravlev Andrey, Shutterstock

Diagnosing Struvite Crystals in Cats

Your veterinarian may perform a urinalysis as part of a routine physical exam before anesthesia or as a secondary to urinary or behavioral issues noted at home. Struvite crystals are readily seen under the microscope and may vary in size but have roughly the same basic shape as a coffin lid.

Your veterinarian might see other findings on the urinalysis, such as red blood cells, white blood cells, and bacteria.

They'll check for other things, as well, such as:
  • How well your cat is concentrating its urine
  • Protein levels
  • Other crystals

Your veterinarian may run the urinalysis in the hospital or send it to a lab for analysis. They may also recommend culturing the urine. Some hospitals even have automatic analyzers that scan the urine and spit out a report faster than humans.

Other tests to assess your cat's bladder health include:
  • Blood work, including a complete blood cell count and biochemistry
  • Ultrasound
  • Radiographs (X-rays)

divider 3 paws

How Do I Care for a Cat With Struvite Crystals?

If your cat has bladder stones associated with their struvite crystals, you and your veterinarian might decide to perform surgery, a cystotomy.

However, in many cases, you don’t have to resort to a cystotomy. Dissolving the crystals and stones is often an option. Your veterinarian will prescribe a specific diet, usually Hill’s c/d or Royal Canin SO, designed to support bladder health and dissolve stones. The important thing to bear in mind is that this diet is usually lifelong. Cats that develop struvite crystals are more likely to develop them again in the future, so dietary management is key. Your cat won’t be able to eat anything but the food, so everyone in the house will need to be on the same page.

Typically, struvite crystals will dissolve within a couple of months. Your veterinarian must monitor the dissolution process with repeat X-rays and urinalysis.

persian cat checked by vets
Image Credit: Beach Creatives, Shutterstock

If your cat has evidence of a urinary tract infection, your veterinarian will prescribe antibiotics. Some cats also need anti-inflammatory medications, such as Onsior.

If your cat stops urinating or is straining to urinate, they need to be evaluated by a veterinarian immediately. In the case of a urinary obstruction, your cat will usually be sedated and have a urinary catheter placed. They may be hospitalized for several days with fluid therapy and medications.

Some cats with an obstruction, especially if they obstruct more than once, may need a perineal urethrostomy, where a larger surgical opening is made to help unblock them.

divider 3 paws

Preventing Struvite Crystals in Cats

If your cat has had urinary crystals, your veterinarian is likely to recommend keeping them on a diet to dissolve struvite crystals. These diets tend to restrict the levels of magnesium and phosphorus. They also help acidify the urine, which decreases the pH, making the formation of struvite crystals less likely.

Some cats are prone to urinary issues when stressed or have anxiety. Your veterinarian might suggest Hill’s c/d MultiCare Stress to help with urinary and stress issues.

You’ll also want to make sure your kitty drinks plenty of water. The easiest way to do this is to give them canned food every day or add water to their food. You might also try using a water fountain, although not all cats will use them.

Your veterinarian will likely recommend regular urinalysis rechecks. If they ask you to collect a sample using non-absorbable litter at home, you’ll want to bring it in immediately for evaluation. Struvite crystals can spontaneously form when urine sits out for an extended period, so collect it and bring it right in, or keep it in the fridge until you bring it in.

cat eating wet tuna food
Image Credit: Svetlana Rey, Shutterstock

divider 3 paws

Frequently Asked Questions

Can Dry Food Cause Struvite Crystals in Cats?

Yes, dry food may increase the possibility of your cat developing struvite crystals because they may not be drinking enough water. Feeding canned food can help with that.

Can Tap Water Cause Struvite Crystals in Cats?

In some cases, tap water might be linked to forming crystals, especially if the water is high in magnesium. If the water is high in calcium, it could cause other crystals. That said, diet is the more likely reason for crystal formation.

divider 3 paws

Conclusion

Struvite crystals can form in cat urine for different reasons, including urinary tract infections and highly concentrated urine. Your veterinarian can help determine the crystals’ significance and recommend treatment, such as diet change.


Featured Image Credit: Pee Paew, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Does My Cat Have a Sense of Humor? The Surprising Vet-Approved Answer

As a cat owner, you may have often wondered whether your cat has a sense of humor. While it’s unlikely that your cat...

Referrals & Second Opinions For Your Cat: Everything to Know

Hi, I’m Dr. Lauren! Read my introduction to learn more about me and my two adventurous cats, Pancake and Tiller. Have you ever...

13 Cat Sleeping Positions Explained (With Pictures)

Are you interested in why your cat sleeps the way they do? You’re not alone. Many cat owners are intrigued by the unorthodox...

Persian Kittens for Sale in Indiana: Breeders List 2026

Catster advocates for adopting before shopping, though we fully understand there are many reasons for seeking a breeder. So, we encourage it to...

More related

Cat Butts: How They Provide Crucial Info About Your Kitty’s Health (Vet-Verified)

Your cat’s butthole may not be the most glamorous aspect of feline anatomy, but it can provide valuable information about your kitty’s health....

My Cat Killed a Mouse, What to Do? Our Vet Answers & Explains

Cats might seem like the perfect pet to have at home, but they’re hunters at heart. What happens when you come home to...

Cat Coin & Dog Dollar: The Changing Nature of Pet Terminology

Hi, I’m Dr. Lauren! Read my introduction to learn more about me and my two adventurous cats, Pancake and Tiller. A rose, by...

15 Free DIY Floor to Ceiling Cat Trees (With Pictures)

If you’ve been a cat parent for any length of time, you already know they love climbing, sleeping in high places, and playing...

Keep reading

9 Vet-Reviewed Signs Your Cat Is Bored & How to Fix It

Heaven forbid your cat should be short on entertainment. If they don’t have enough to do, you might notice a few different behaviors they’re using to communicate that they are bored to tears. Over time, boredom can lead to frustration...

A cat lying on bathroom floor

Will My Male Cat Be More Affectionate After Neutering? Vet-Reviewed Facts & FAQ

An unneutered male cat can be… a handful, to say the least. Otherwise known as tomcats, there are a multitude of reasons to have them neutered. To answer the question, yes—a male cat will most likely be more affectionate and...

cat playing with its owner

11 Best Cat Foods in Canada in 2026 – Reviews & Top Picks

Did you know that around 50%-60% of Canadian pets are considered obese?1 Obesity is a serious health concern for cats as it increases their risk of developing potentially life-threatening conditions like cancer and heart disease.2 The good news is that...

grey cat eating food

Can Cats Be Gay, Bisexual, or Lesbian? Vet Reviewed Feline Sexuality Facts

Some of the behaviors our pets exhibit mimic our own, but many of their quirks seem strange. It’s difficult to interpret a feline’s behavior when you relate their actions to those of humans. One of the most common questions people...

two gay cats

Do Cats Get Jealous of Dogs? Feline Emotions Explained (Vet-Reviewed)

Jealousy is a complex emotion that humans experience when they have feelings of insecurity or fear. While we don’t typically think of our cats as having similar feelings as we do, they appear to be capable of more than we...

Golden Retriever and British Shorthair accompany their owner

Why Do Cats Like Milk? 2 Vet-Approved Reasons & FAQ

A cat lapping at a bowl of milk is something that we all think of when it comes to felines. This perception comes from farm cats from bygone eras lapping at the fatty topping of unprocessed cow’s milk and popular...

two cats drinking milk from the same bowl

When Are a Cat’s Teenage Years? Vet-Reviewed Facts & Useful Tips

Just like humans, cats go through a stage that tends to correlate with “teenage” behavior. Some of it is cute and funny, and some of it is irritating and frustrating. Fortunately, the cat teenage years are not all bad, and...

Bengal kitten playing

Can a Neutered Male Cat Still Get a Female Pregnant? Vet-Verified Facts

Neutering or spaying your cat is a crucial part of responsible pet ownership. It prevents accidental litters, some behavioral problems, and reproductive conditions and ensures you don’t contribute to overpopulation. However, a neutered male cat can still get a female...

tabby cats walking and twisting their tail to a heart shape