Cats, our beloved feline companions, can unfortunately suffer from the formation of solid waste particles in their urine, known as urine crystals and bladder stones. These conditions arise when waste materials become concentrated within the bladder, often exacerbated by dehydration or a diet consisting primarily of dry food. While crystals are microscopic, they can grow over time, eventually developing into stones that can fill the entire bladder. These formations can occur in the kidneys, ureters, bladder, or urethra, potentially obstructing urine flow and leading to severe consequences such as kidney damage or a life-threatening urinary blockage.
Crystals vs. Stones: What’s the Difference?
Essentially, urine crystals are the fundamental building blocks of bladder stones. The specific type of crystal or stone that forms depends on various factors, including urine acidity, concentration, genetics, diet, and other underlying health issues. Some stones may even be a combination of different crystal types.
Common Types of Feline Urinary Crystals and Stones
Struvite Crystals and Stones
Also known as magnesium ammonium phosphate stones, struvite is one of the two most prevalent types found in cats. Factors like breed, sex, and diet contribute to their formation. These are particularly common in cats fed mostly dry food, as magnesium ammonium phosphate, often referred to as “ash” in pet food, is a contributing factor. While the condition is often more severe in male cats, females can also be affected. Struvite stones can sometimes be dissolved with a prescription diet, though surgery may occasionally be necessary. Preventing their formation can often be achieved by feeding an exclusively wet 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, and specific breeds like Persians and Himalayans are more predisposed. Calcium oxalate stones are generally more challenging to manage than struvites and often necessitate surgical removal. Following surgical intervention, a prescription diet designed to regulate calcium and oxalate levels in the urine can help manage the condition, with canned food being the preferred option over dry kibble.
Recognizing the Symptoms
The symptoms associated with bladder crystals and stones in cats can vary, but often include:
- Straining to urinate
- Urinating in or around the litter box
- Blood in the urine
- Frequent urination of small amounts
- Lethargy
- Vocalization during urination
- Crying or pain when the abdomen is touched
- Reduced appetite
While symptoms for both crystals and stones can appear similar, stone-related issues tend to persist longer. Male cats experiencing a urinary emergency may exhibit signs such as extreme distress, repeated attempts to urinate with no success, and a swollen or painful abdomen.
Underlying Causes
Several factors can contribute to the development of urine crystals and bladder stones in cats, including pre-existing health conditions, breed predispositions, and age. However, a significant contributing factor, particularly for common struvite crystals and stones, is a diet high in dry food. The exact causes of calcium oxalate stones are less clear, but diet remains a major influence. Some cats are less tolerant of urine with high concentrations of calcium and/or oxalate, leading to crystal formation. Therefore, long-term management often involves specialized therapeutic urinary diets prescribed by a veterinarian to keep waste product levels below the threshold for crystal formation. Due to their naturally low water intake, many cats are chronically dehydrated, which further promotes the formation of both types of stones, highlighting the importance of wet food.
Veterinary Diagnosis
Veterinarians employ a range of diagnostic tests to identify stones, crystals, or blockages:
- Bloodwork: This helps identify any underlying health issues that might contribute to stone formation or assess the severity of a blockage.
- Urinalysis: This examination 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 Approaches
The treatment strategy for crystals and stones is tailored to the specific type, size, and location of the formation, as well as the cat’s overall health. Female cats can often pass small stones naturally or with the aid of a flushing procedure called voiding urohydropropulsion.
Male cats, however, face a higher risk of urinary blockage due to their narrower urethra, where even small stones can cause an obstruction. Some stones can be dissolved within two to four weeks by initiating a therapeutic urinary diet, which requires veterinary approval. It’s important to note that larger stones, even if partially dissolved, can still cause blockages. Surgical removal is necessary for stones that are too large to dissolve or pose an immediate risk. Most calcium oxalate stones do not respond to dietary dissolution and require surgical extraction. A urinary blockage typically necessitates several days of hospitalization for stabilization and a two-week recovery period. If a stone is causing a blockage, a veterinarian will insert a catheter to flush the stone back into the bladder, after which it must be either dissolved or surgically removed to prevent recurrence.
Recovery and Long-Term Management
A cat’s recovery from urine crystals and bladder stones hinges on the type of stone and their medical history. Diet is a cornerstone of management, with various commercial diets formulated to treat and prevent common crystal and stone types. Increasing water intake is another crucial strategy, as concentrated urine is more conducive to crystal formation. Feeding canned food is an effective method for boosting hydration.
Prevention Strategies
It’s vital to understand that crystals and stones can recur. If your cat has a history of these issues, prioritize increasing their water intake and adhering strictly to the diet recommended by your veterinarian. Deviating from prescribed therapeutic diets with other foods, treats, or snacks can jeopardize the carefully balanced urine concentration and lead to recurrence. Regular recheck urinalyses can help detect developing problems before symptoms arise. Ensure urine samples are fresh, as struvite crystals can form in samples left standing.
For cats without a history of urinary issues, feeding a high-quality, all-canned diet is the most effective preventive measure. Encourage water consumption through various means, such as providing water fountains, running water, or lightly flavoring their water with tuna juice.
