Urinary crystals and bladder stones are serious conditions that can affect cats, leading to significant health complications if left untreated. These solid formations develop within a cat’s urinary tract when waste materials become concentrated in the urine. While crystals are microscopic, they can grow and aggregate over time to form stones, some of which can become as large as the bladder itself. These formations can obstruct urine flow, potentially causing kidney damage or a complete urinary blockage, which can be fatal for cats.
The Difference Between Crystals and Stones
Essentially, crystals are the foundational building blocks of bladder stones. The type of crystals and stones that form depends on various factors, including the acidity and concentration of the urine, a cat’s genetic predisposition, their diet, and other underlying health conditions. It’s also common for a stone to be composed of more than one type of crystal.
Common Types of Urinary Crystals and Stones in Cats
There are two primary types of crystals and stones frequently found in cats:
Struvite Crystals and Stones
Also known as magnesium ammonium phosphate stones, struvite formations are among the most common in cats. Their prevalence is influenced by a combination of factors such as breed, sex, and diet. They are particularly common in cats that primarily consume dry food, as the mineral content, often referred to as “ash” in pet foods, can contribute to their formation. While struvite crystals can cause severe disease, especially in male cats, females are also susceptible. In some cases, these can be dissolved with a specific prescription diet, but surgery may occasionally be necessary. Preventing struvite formation can often be achieved by feeding cats an exclusively canned food diet.
Calcium Oxalate Crystals and Stones
These stones form from the combination of calcium and oxalate waste products in the urine. They are most frequently observed in middle-aged to older, neutered male cats, as well as certain breeds like Persians and Himalayans. Calcium oxalate stones are generally more resistant to dissolution compared to struvites and often require surgical removal. Post-surgery, management typically involves feeding a prescription diet formulated to control the levels of calcium and oxalate byproducts in the urine. As with struvites, a wet food diet is preferred over dry food for managing calcium oxalate issues.
Symptoms of Urinary Crystals and Bladder Stones
Cats experiencing urinary crystals or bladder stones may exhibit several symptoms, which can vary in intensity and duration. Signs of a potential urinary emergency, particularly in male cats, include trouble urinating. While symptoms for both crystals and stones can overlap, those associated with stones tend to persist longer.
Causes of Urinary Crystals and Bladder Stones
Several factors can contribute to the development of urinary crystals and stones in cats, including underlying health conditions, breed, and age. However, a dry food diet is a significant contributing factor in the majority of cases, especially for common struvite crystals and stones. The exact causes of calcium oxalate crystals and stones are less precise, but diet remains a major influence. Some cats are more prone to crystal formation when their urine is heavily saturated with calcium and/or oxalate. Long-term management often involves specially designed therapeutic urinary diets, which are only available via prescription. These diets work by adjusting the levels of waste products in the urine to below the threshold for crystal formation.
A contributing factor for both types of crystals and stones is that most cats do not drink sufficient water, leading to chronic dehydration. This is why a diet rich in moisture, such as wet food, is highly recommended.
Veterinary Diagnosis
Veterinarians employ a range of diagnostic tests to identify stones, crystals, or blockages in cats:
- Bloodwork: This helps identify underlying health issues that might contribute to crystal formation or assess the severity of a blockage.
- Urinalysis: This analysis evaluates the urine’s concentration, acidity, and the presence of infection or crystals.
- Imaging: X-rays or ultrasounds are used to visually detect the presence and location of stones.
Treatment Options
The treatment approach for urinary crystals and stones depends on the type, size, and location of the stone, as well as the cat’s overall health. Female cats can often pass small stones naturally or with the aid of a procedure called voiding urohydropropulsion. However, male cats face a higher risk of urinary blockage, even with small stones, due to the narrow passage of their urethra.
Some stones can be dissolved within two to four weeks by starting a therapeutic urinary diet, which requires veterinary approval. Larger stones, however, may need surgical removal, especially if they pose a risk of blockage even as they dissolve. Most calcium oxalate stones do not dissolve with prescription diets and necessitate surgical intervention.
A urinary blockage is a medical emergency that typically requires several days of hospitalization for stabilization and one to two weeks for full recovery. If a stone obstructs urine flow, a veterinarian will insert a catheter to flush the stone back into the bladder. The stone must then be either dissolved or surgically removed to prevent recurrence.
Recovery and Management
A cat’s recovery from urinary crystals and bladder stones is contingent upon the stone type and their medical history. Diet is the primary management strategy, with various commercial diets available to treat and prevent common crystal and stone types. Increasing water intake is crucial, as concentrated urine increases the likelihood of crystal and stone formation. Feeding canned food is an effective method for boosting a cat’s water consumption.
Prevention Strategies
It’s important to recognize that urinary crystals and stones can recur in cats. If your cat has a history of these issues, prioritize increasing their water intake and adhering strictly to the veterinarian-recommended diet. Deviating from this diet with other foods, treats, or snacks can jeopardize the carefully balanced urine concentration required for prevention. Regular recheck urinalysis can help detect emerging problems before symptoms appear.
For cats without a history of urinary issues, feeding a high-quality, all-canned diet is the most effective preventative measure. Encouraging increased water consumption can also be achieved through various methods, such as using water fountains, leaving a faucet dripping, or adding a small amount of tuna juice to their water.
