If you share your life with a cat, you might know that litter box problems aren't uncommon. However, the particular affliction of bladder stones in cats doesn't receive the attention that it should. Read on to learn about the most common types of feline bladder stones — calcium oxalate and struvite — including how to prevent and treat them.

Basic Facts About Bladder Stones in Cats

Bladder stones, or uroliths, are simply organized accumulations of hardened minerals that are found in urine. They can occur anywhere along the urinary tract, from the kidneys all the way to the urethra — the narrow tube that carries urine from the bladder to the outside of the body.

Stones range in size. Your cat could have a tiny stone or one the size of their bladder. Stones also range in shape and color. They can be smooth or have jagged edges. Stones pose problems because they can damage the surrounding tissue, cause inflammation, scar tissue and predispose a cat to infection, especially if they have rough or jagged edges.

Crystals vs. Stones

If you've heard of urine crystals, you might be wondering how they differ from bladder stones. According to the Merck Veterinary Manual, when crystals clump together and grow, becoming visible to the naked eye, the result is called a stone. However, it should be noted that crystals may be present in certain urinary environments that favor the formation of a stone but is not a definitive precursor.

Clinical Signs of Bladder Stones in Cats

The signs that cats with bladder stones display differ depending on where the stones are located in the urinary tract. Many times, cats with bladder stones exhibit no signs at all. Other times, the stones may cause bladder irritation or infections, which may present as frequent trips to the litter box, frequent urination, blood in the urine, vocalizing while urinating, urinary accidents and decreased urination.

If a urinary stone becomes stuck, it may cause urinary obstruction also known as a blocked urethra so the cat cannot urinate at all. This is a life-threatening condition that requires prompt intervention. This is most often seen in male cats. If you notice your cat trying to urinate, but doing so unsuccessfully, you should see your veterinarian promptly. It's also important to consider that a cat with urinary obstruction may act like they're constipated. While the behavior may look similar, the results can be drastic — if you notice this behavior, it is likely a good idea to call your local vet to get their recommendation.

Striped grey tabby standing alongside a plastic covered litter box and garbage bin in a house.

Types of Bladder Stones in Cats

The two most common types of bladder stones in cats are struvite stones and calcium oxalate stones. According to the American College of Veterinary Surgeons, while the development of these stones is complex, a cat's food may play a role. They also rarely form secondary to bladder infections in cats.

Radiographs and a microscopic exam of urine sediment may provide indications as to what type of stone your cat has. However, the identity of a stone cannot be determined unless it is collected and analyzed.

Calcium Oxalate Stones

Calcium oxalate stones are the most common urinary stone in cats, according to the Merck Veterinary Manual. They're most often seen in middle-aged to older cats. Breeds most likely to develop calcium oxalate stones include the Ragdoll, British shorthair, exotic shorthair, Himalayan, Persian and Scottish fold. Calcium oxalate stones can form in overly acidic urine. They may be seen in cats with elevated blood and urine calcium levels secondary to a condition called idiopathic hypercalcemia or in cats with chronic kidney disease.

This type of stone requires surgical removal. Infections and underlying conditions must also be treated. Once the stones have been removed, switching your cat to a therapeutic food formulated to reduce urine mineral content and increasing their water intake — by switching them to wet food, for example — may help prevent a recurrence. It's necessary to have your cat adhere to your veterinarian's recommended meal plan.

Struvite Stones

Struvite stones are typically found in younger cats who've been neutered. Unlike calcium oxalate stones, struvite stones in cats tend to form in highly concentrated alkaline urine. While any breed can be affected, those most at risk are the domestic shorthair, exotic shorthair, Ragdoll and Himalayan. Cats who consume high amounts of magnesium, phosphorus, calcium, chloride and fiber are also more likely to develop struvite stones.

A special therapeutic food, such as Hill's Prescription Diet, can help dissolve struvite stones. Therapeutic urinary foods come in a variety of flavors and forms and therapeutic treats may be available so your cat will not be deprived. In many cases struvite stones can be dissolved quickly. One study showed that stones were, on average, 50% smaller in just 2 weeks and the average time to completely dissolve stones in about a month. In most cases, it's recommended that a cat remain on a therapeutic food to prevent stones from returning. This is becase while a cat that may no longer be symptomatic of urinary issues, recurrence is possible if the cat resumes eating a food that contributed to stone formation in the first place. Keeping your cat on a pet food formulated for urinary health may help extend the time between urinary problems.

While bladder stones in cats have a high recurrence rate, they can be successfully treated. Together you and your veterinarian can determine the right therapy or combination of therapies to keep the stones at bay.

Dr. Laci Schaible Dr. Laci Schaible

Dr. Laci Schaible is a small animal veterinarian, veterinary journalist, and a thought leader in the industry. She received her Doctor of Veterinary Medicine from Texas A&M University and her Masters in Legal Studies from Wake Forest University.

Related articles

Your Cat is Always Hungry: What Should You Do?

Learn why your cat might show signs of being overly hungry, if there could be an underlying medical concern, and options to help them control their hunger.

Differences Between Male and Female Cats

Consider these behavior and appearance differences between male and female cats before choosing a forever friend.

Changing Cat Food: How to Do It Safely

Cat's nutritional needs change as they age, so it is important to know when to change their food to keep them healthy and active.

Managing Clingy Cats: Do I Have a Velcro Kitty?

Learn reasons why some cats are excessively clingy, how you can help curtail this behavior, and considerations when potentially adopting a Velcro kitty.

A Guide to Trimming Cat Claws

Learn helpful tips for trimming your cat's claws, including nail clippers you'll need and how short you should trim her claws.

What Is Heartworm in Cats? Symptoms, Diagnosis & Prevention

Heartworm in cats is a serious disease that can affect outdoor and indoor pets — but it's also totally preventable. Learn what pet parents need to know.

How to Tell If Your Cat Is Lonely

Do cats get lonely? What can you do to help? Learn some common signs to tell if your cat is lonely and steps you can take to try and cheer them up.

Coccidia in Cats: Symptoms, Treatment & Prevention

While coccidia in cats is a common infection, it's good to know the common symptoms, how it's treated and what you can do to prevent it. Learn more.

Cat Aggression: How to Calm Them Down

Learn how to identify causes of aggression in your cat, how you can help calm them down or diffuse an aggressive situation, and when a vet visit is needed.

Why Is My Cat Eating Litter?

Learn if your cat's peculiar behavior of eating litter or feces is something to be concerned about, why they do it, and when you should consult a vet.

Kitten's Development Milestones: First Weeks & Months

Follow this timeline to learn the weekly & monthly progression of your kitten's development, including when to expect her to start walking & needing vaccines.

Cat Play: How to Keep Your Kitty Engaged

Keep your cat both mentally and physically active with these fun tips for play and exercise even when you're not home.

All About Your Cat's Sleeping Habits

Learn all about your cat's sleep schedule, why she seems to be most active during twilight hours and what it means to be a crepuscular kitty.

Why Adopting a Free Kitten Isn't Always a Good Idea

If you're considering adopting a free kitten, learn some of the things to keep in mind, from potential health problems to socialization issues.

Do Cats Like to Be Petted?

Petting & picking up a cat can be tricky, but she'll give you signs to show she's ready. Learn her favorite spots to be petted and handling techniques.

The Science Behind Your Cat's Traits

Curious to know more about your cat? From how fast she runs to how high she can jump, learn what science has found out about your cat's distinct traits.

How to Care for an Injured Cat

Cat injuries require special attention—earn how to recognize a cat injury, details about cat wound care and recommendations for helping cats heal at home.

Weight Gain in Your Cat & How You Can Help

Learn the different factors that might be contributing to your cat's weight gain, and how bigger doesn't always mean better.

Explaining Your Cat's Greeting

Learn about the different types of greetings cats can show you, such as head butting or slow blinking, and how to interpret each of her signals.

Six Ways to Socialize Your New Cat

Socializing a cat into a new home takes patience and love. Discover these cat socialization tips to help an adopted cat adjust to her family.