Cat Urinary Crystals: Causes, Diagnosis, and Veterinary Management

For veterinarians and veterinary students, knowledge of the causes and symptoms of cat urinary tract crystals is important. It will enable them to use effective diagnostic and treatment procedures for the disease. Effective management will eliminate the occurrence of acute emergencies. 

While this article covers the basics of what causes urinary crystals in cats and why diagnosis matters, the actual diagnosis is in the details.  Watch the full video of our webinar on it to see Dr. Joseph Bartges (DACVIM, DACVN) demonstrate real imaging, urinalysis techniques, and case-based clinical decision-making that text alone cannot show.

Before we study diagnostics, it’s essential to understand why urinary crystals form in cats.

Why Urinary Crystals Form in Cats

Supersaturation of urinary minerals leads to the formation of urinary crystals. The tiny crystals could accumulate and evolve into stones within the bladder and/or clogs in the urethra.

Many factors govern the formation of the crystals. A few of them are: 

• Urine pH
• Mineral concentration
• Hydration status
• Existing metabolic
• Dietary problems

It becomes easier to classify the particular kinds of crystals and also to choose the optimum treatment if these factors are known.

Types of Crystals in Cats

Urinary crystals in cats are solid formations that develop from minerals in the urine. They can vary in composition, each type forming under specific conditions and potentially leading to discomfort or urinary complications. 

• Struvite Crystals: Made of magnesium ammonium phosphate. Struvite crystals are usually formed when urine is alkaline or neutral in pH. Struvite crystals may not be associated with urinary infection. However, when present persistently, they can cause irritation to the lower urinary system.
• Calcium oxalate crystals: These crystals form in an acidic urine environment. These crystals are typically found in middle-aged and older cats. Unlike struvite stones, these stones\ crystals do not often dissolve by changing a cat's diet. Surgery is often necessary in cases of obstruction.

There are also other forms of crystals that can be found, such as cystine crystals or urate crystals. Such forms of crystals can be rare in domestic cats. By knowing the form of crystals, it becomes easier to explain symptoms that cats can develop.

Identifying Urinary Crystals in Felines Through Clinical Signs

Cats with urinary crystals may have subtle or quite evident symptoms. Main symptoms include:

• Straining during urination, often with little or no urine output
• Frequent visits to the litter box
• Urination outside the litter box
• Blood in urine
• Vocalization or Discomfort

Male cats are especially prone to urinary tract blockages due to their narrower urethras. This anatomical difference makes it easier for crystals or stones to obstruct the urinary flow. If not treated promptly, urinary tract blockages in cats can quickly become a life-threatening condition.

Not all cats with urinary crystals will have symptoms. Cats might have crystals in the urine discovered incidentally during routine urinalyses. In other instances, symptoms should receive immediate attention. 

Monitoring for symptoms will help veterinarians identify the best test for a cat with crystals in the urine.

Diagnostic Protocols for Cat Urinary Crystals

To make an appropriate diagnosis, the healthcare provider relies on the patient's history, examination, laboratory testing, and imaging.  Each step builds a clearer picture of urinary tract health.

1. Urinalysis and Sediment Exam

New urinalysis results confirm the presence of crystals in the urine. It also tests pH levels, specific gravity, and the presence of inflammation and infection. 

Standard urinalysis is critical, but technique matters. In the webinar, Dr. Bartges demonstrates his specific “line smear” method for differentiating true bacteria from background sediment artifacts.

2. Urine Culture When Needed

UTIs in cats aren’t very frequent. However, a culture and sensitivity test should be performed in case of infection. This helps determine whether a urinary tract infection is present, as infection may alter urine characteristics, but it is not a common primary cause of crystalluria in cats.

A confirmed infection can complicate existing lower urinary tract disease. Infection may alter urine pH and inflammatory status, which can contribute to lower urinary tract infection signs, although it is not a typical primary driver of crystal formation in cats.

3. Imaging

Radiographs or ultrasound studies are used to confirm the presence of stones. Obstruction and urinary tract morphology can be identified at this point. While ultrasounds are useful, Dr. Bartges explains in the webinar why a lateral radiograph is often the superior first step for identifying specific stone densities that ultrasounds might miss.

Veterinarians seeking more in-depth guidance about urinary crystals in cats can explore our Diagnosis and Management of FLUTD webinar. The webinar includes case studies, stepwise diagnostic protocols, and imaging interpretation strategies.

Treatment Strategies for Cats with Crystals

Once the type and severity of the crystal are identified, treatment can be tailored specifically to the patient’s condition. There are many approaches for the treatment of cats with urinary tract crystals, depending on the severity of the condition.

Here we will discuss a few of them:

Acute Management:

Obstructed cats will need emergency catheterization and fluid support. Hospitalization is necessary to stabilize the kidneys. Furthermore, the electrolytes and the pain will also be relieved. It is important to take prompt action to prevent renal failure and other serious outcomes. 

Medical Dissolution and Diet:

Struvite stones may dissolve with specially formulated prescription diets that alter urine pH and limit mineral availability. Consistent and strict adherence to these diets is essential for success. In contrast, calcium oxalate stones do not respond to dietary changes and typically require surgical removal.

Hydration and Monitoring:

Promoting hydration is among the simplest and most effective methods. Use of water fountains or feeding your cat damp food will help the cat increase the amount of fluid it consumes. In return, this will help dilute the urine, hence preventing the formation of crystals.

Emphasis on hydration is important for treatment. Moreover, this has laid the groundwork for the overall well-being of the urinary tract. Keeping this point in mind, effective cat care has to go beyond relief methods for urinary infections.

Effective treatment naturally transitions to long-term prevention, which is crucial in cats with prior urinary issues.

Long-Term Management and Prevention

To prevent recurring crystals in the urinary system, the following are required, starting with dietary changes:

• Prescriptive diets: Aims to help control minerals and pH. This will help prevent the formation of crystals.

• Since stress is a major factor in idiopathic cystitis, the webinar details specific 'multimodal environmental modifications' that have been clinically shown to reduce recurrence.
• Monitoring high-risk cats: Male cats with prior obstruction remain at elevated risk for lower UTD episodes.

Regular follow-ups make it possible to notice early occurrences of recurrent obstruction. Through preventive care practices, veterinarians can improve prognoses for cats' quality of life. As a result, timely treatment of urinary tract crystals in cats is possible.

Final Thoughts

Conclusively, urinary crystals in cats should be interpreted alongside clinical signs, as crystalluria may be incidental in asymptomatic patients. Together with symptoms, they require thorough evaluation and prompt treatment. 

A timely diagnosis, along with appropriate care tailored to urinary crystals, will help avoid complications like obstruction, which can be fatal. However, when it comes to veterinarians, the key to success is a planned approach that incorporates diagnosis, dietary care, hydration plans, and patient follow-up. 

With effective prevention and follow-up, pet owners and veterinary professionals can maintain their urinary health. Effective management not only leads to improvement but also increases the quality of life for the cat.

FAQs

What is FLUTD in cats?

FLUTD in cats refers to a group of disorders affecting the lower urinary tract. It is crucial to pinpoint the exact cause as it will directly influence the selection of therapies and preventive measures.

How do you treat urinary crystals in cats?

Treatment depends on the crystal type, clinical severity, and risk of obstruction. Struvite crystals may dissolve with prescription diets and increased water intake. Calcium oxalate crystals typically require physical removal. 

Can a UTI cause crystals in urine in cats?

In rare cases, it is possible. Bacterial infection may alter urinary characteristics; however, UTIs are uncommon in cats and are not a typical primary cause of urinary crystal formation