Bladder Stones in Cats: Causes, Symptoms & Treatment

Bladder Stones in Cats: Understanding a Common Urinary Condition

Bladder stones, also known as uroliths, are mineral deposits that form in the bladder of cats and can cause significant discomfort and health complications. These stones develop when excessive amounts of certain minerals in your cat’s urine begin to clump together with other substances found within the bladder. Understanding the causes, symptoms, and treatment options for bladder stones is essential for any cat owner concerned about their pet’s urinary health.

What Causes Bladder Stones in Cats?

Bladder stones can form due to various factors that contribute to an imbalance in your cat’s urinary chemistry. The development of these stones is rarely attributable to a single cause but rather results from a combination of factors that create an environment conducive to stone formation.

Several key factors can increase the likelihood of bladder stone development in cats:

• Poor diet lacking proper nutrition
• Chronic dehydration and insufficient water intake
• Bladder or urinary tract infections
• Bladder inflammation caused by crystal formation
• Extremes in urine pH levels (excessively alkaline or acidic)
• Breed predisposition to stone formation
• Congenital liver shunt conditions
• Certain medications or dietary supplements

Research indicates that overweight male cats face an increased risk of developing bladder stones compared to their female or leaner counterparts. Age also plays a role, with certain stone types being more prevalent in specific age groups.

Types of Bladder Stones in Cats

Veterinarians have identified several different types of bladder stones in cats, but two types are significantly more common than others: calcium oxalate and struvite stones. Understanding the differences between these stone types is crucial because each requires different treatment approaches.

Calcium Oxalate Stones

Calcium oxalate stones typically develop in cats with highly acidic urine. These stones are particularly common in felines with elevated urine and blood calcium levels and in cats suffering from chronic kidney disease. Calcium oxalate stones most frequently appear in cats between five and fourteen years of age, making them a concern for middle-aged and senior cats.

The formation of calcium oxalate stones is challenging to prevent once a cat has developed them, as the underlying metabolic factors that contribute to their development often persist throughout the cat’s lifetime.

Struvite Stones

Struvite stones are most common in cats with highly alkaline urine, which can result from urinary tract infections, though infections are not always present. These bladder stones frequently occur in cats who consume high amounts of magnesium, phosphorus, calcium, chloride, and fiber through their diet.

A genetic factor may also influence a cat’s risk of developing struvite stones. Siamese cats, in particular, appear to have a genetic predisposition to struvite stone formation, suggesting a hereditary component to this condition.

Clinical Signs of Bladder Stones

The most common signs indicating that your cat may be suffering from bladder stones include blood in the urine (hematuria) and straining to urinate (dysuria). Bleeding occurs because the stones rub against the bladder wall, irritating and damaging the delicate tissues. Straining happens due to inflammation and swelling of the bladder walls or the urethra, the tube connecting the bladder to the outside of the body. Straining may also result from muscle spasms triggered by irritation.

Additional clinical signs you should watch for include:

• Frequent urination in small amounts of urine
• Painful or difficult urination
• Urinating outside the litter box
• Straining to urinate without producing urine
• Abdominal pain or discomfort
• Lack of energy or lethargy
• Crying out in pain during urination
• Decreased appetite

Urinary Obstruction: A Medical Emergency

While many cats experience discomfort from bladder stones, the condition becomes a medical emergency when bladder stones cause a complete urinary obstruction. This occurs when your cat’s urethra becomes blocked with a stone, preventing your cat from urinating at all.

Signs of urinary obstruction include:

• Complete inability to urinate
• Vomiting and nausea
• Loss of appetite
• A firm, distended stomach
• Lethargy and depression
• Toxic buildup in the bloodstream

A complete urinary blockage is a life-threatening emergency. Urine can back up into the kidneys, and without treatment, death may occur in as little as two to three days as toxins build up in your cat’s body. If you suspect your cat has a urinary obstruction, seek immediate veterinary care.

Diagnosis of Bladder Stones

Diagnosing bladder stones involves a comprehensive approach combining physical examination, laboratory testing, and imaging studies. Your veterinarian will begin by obtaining a detailed history of your cat’s symptoms and performing a thorough physical examination.

Routine blood and urine tests are essential diagnostic tools that help veterinarians identify bladder stones and detect any resulting urinary tract infections. Urinalysis may reveal microscopic crystals, though it is important to note that some cats have stones without crystals, and conversely, some cats have crystals without stones.

Imaging studies such as radiography (X-rays) or ultrasound are often used to visualize and confirm the presence of stones in the bladder. These imaging techniques help determine the size, number, and location of stones, information that is crucial for determining the appropriate treatment approach.

Treatment Options for Bladder Stones

The best treatment for your cat’s bladder stones depends upon the type of stones that your cat has. Veterinarians have several options available to address this condition, ranging from non-surgical medical management to surgical intervention.

Surgical Treatment

The fastest solution for bladder stone removal is to perform a cystotomy, a surgical procedure to open the bladder and remove the stones. This routine surgery is a common choice and cats usually make a speedy postoperative recovery with an excellent success rate. However, it may not be the best option for patients with other health concerns or those for whom general anesthesia could be risky.

Cats with a complete urethral obstruction caused by large stones require immediate surgical intervention. In some cases, a cystotomy may not be necessary if the obstruction can be relieved by passing a catheter, especially if obstruction results from soft plugs of crystals and mucus or urethral spasms.

For calcium oxalate stones specifically, surgical removal is often necessary since these stones cannot be dissolved through dietary or medical management. In some cases, stones can be fragmented with a laser during cystoscopy, with fragments then being flushed out, though cystotomy remains the more common approach.

Medical Treatment with Therapeutic Diet

Another treatment option involves attempting to dissolve bladder stones with special therapeutic diets designed specifically for feline urinary health. Some types of bladder stones, particularly struvite stones, can often be dissolved with the help of therapeutic diet and medications.

Popular prescription diets used for this purpose include Hill’s Prescription Diet C/D, Purina UR/StOX, and Royal Canin Urinary SO. Struvite stones can be treated medically with specialized food formulations that create a urine undersaturated with the crystals responsible for stone formation. This undersaturation literally causes the urolith to dissolve in the urine and be urinated out, though this is a slow and gradual process.

The advantage of this approach is that it avoids surgery and can be a good choice for some cats. However, this method has several disadvantages:

• The dissolving process takes considerable time
• Some stone types cannot be dissolved through diet alone
• Requires strict adherence to the prescription diet
• Requires regular monitoring through urine analysis and imaging

Supportive Care

In cases of urinary obstruction, cats typically require several days of hospitalization to stabilize, with a full recovery typically taking one to two weeks. Supportive care may include fluid administration, catheterization, and pain management while awaiting definitive stone removal or dissolution.

Prevention of Bladder Stones

While not all bladder stones can be prevented, several strategies can help reduce the risk of stone formation in your cat:

• Ensure adequate hydration by providing fresh water and wet food
• Feed high-quality, balanced nutrition appropriate for your cat’s age and health status
• Maintain your cat at a healthy weight
• Address urinary tract infections promptly
• Regular veterinary check-ups to monitor urinary health
• Follow prescribed preventive diets if your cat has a history of stones

Frequently Asked Questions

Q: Can all bladder stones be dissolved with diet?

A: No. Calcium oxalate stones cannot be dissolved and require surgical removal. Struvite stones and some other types may respond to therapeutic diets, but calcium oxalate stones necessitate surgical intervention.

Q: How long does it take for bladder stones to dissolve with diet?

A: The timeline varies depending on the stone type and individual cat factors, but the process is generally slow and gradual. Most cats experience relief from symptoms relatively quickly after starting an appropriate diet.

Q: Is surgery necessary for all cats with bladder stones?

A: Not necessarily. Some stones, particularly struvite stones, may dissolve with appropriate diet and medication. However, calcium oxalate stones and cases of complete urinary obstruction typically require surgical intervention.

Q: What is the recovery time after cystotomy surgery?

A: Cats typically make a speedy postoperative recovery from cystotomy surgery, with most returning to normal activities relatively quickly. However, follow your veterinarian’s post-operative care instructions carefully.

Q: Can bladder stones recur in cats?

A: Yes, bladder stones can recur, which is why ongoing preventive measures, including dietary management and regular monitoring, are important for cats with a history of stone formation.

Q: Is urinary obstruction life-threatening?

A: Yes, complete urinary obstruction is a medical emergency. Without treatment, death can occur within two to three days as toxins accumulate in your cat’s body. Immediate veterinary intervention is essential.