Feline Urinary Crystals: Signs, Symptoms, and Solutions

by | Jul 24, 2022

As amazing and resilient as cats are, they are susceptible to infections and illnesses just like any other animal. As pet parents we want our feline family members to be happy and healthy for as long as possible. A condition that doesn’t get a lot of air time is the formation of urinary crystals. This ailment can affect any domestic cat, and if not treated promptly, can have serious consequences.

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Cat urine is made up of the same basic components as our own, urea, ammonia, minerals, uric acid, and creatinine, but it’s more concentrated than most mammals. Small amounts of crystallized minerals are to be expected in most cat urine, but they are typically small enough to freely pass through the urinary tract. If not broken down by uric acid, these microscopic crystals can bind together, creating larger crystals known as uroliths that can irritate the lining of the bladder and urinary tract. In some cases, urinary crystals can even block the flow of urine entirely, a condition that can become fatal in just a few hours.

Why or when urinary crystals form is not clearly understood but there are some circumstances that we know can increase the chances of a particular cat developing them. Certain diseases, like diabetes and kidney disease, can encourage the formation of crystals. Specific breeds, such as Siamese, Persian, and Burmese cats, are also slightly more prone to developing urinary crystals. While both male and female cats develop these crystals, due to the narrowness of their urethra, male cats are more likely to develop crystals that block the flow of urine completely.


There are several varieties of crystals that can form in the urine. The urinary crystals that are most likely to affect cats include:

  • Struvite—Struvite crystals, made up of magnesium, ammonium, and phosphate, are the most commonly seen form of urinary crystals in feline patients. They are frequently seen in conjunction with urinary tract infections.
  • Calcium Oxalate—These are rarer than struvite stones but are becoming more common due to the higher acidic content found in modern cat foods.
  • Bilirubin—Bilirubin crystals are not commonly found in cats and usually indicate liver malfunction.
  • Ammonium Urate—Ammonium urate crystals are quite rare, and the reason for their formation is poorly understood. These large, irregularly shaped crystals are exceptionally difficult to dissolve, making them more likely to require surgical remedies.


, Feline Urinary Crystals: Signs, Symptoms, and Solutions, The Comforted Kitty

While some of the symptoms of crystalluria are easy for most pet parents to miss, such as the appearance of fine grains in the urine, most are more obvious. Indicators of urinary crystals can include:

  • Frequent urination
  • Straining to urinate
  • Mewling while using the litter box
  • Missing the litterbox
  • Excessive cleaning of genitals
  • Bloody urine
  • Refusal to eat or poor appetite
  • Extreme irritation
  • Lethargy and depression
  • Abdomen that is swollen or tender to the touch

Urinary crystals are a serious threat to the health of domestic cats. Cats that show signs of crystalluria should be taken to a veterinary professional without delay.

What to Expect at the Vet

There are several tests that your veterinarian may request to diagnose your cat’s urinary crystals. Some urinary crystals are large enough to feel when the abdomen is palpitated, but a radiograph or ultrasound imaging is often needed to detect uroliths. In most cases, a urinalysis will be obtained as well. The urinalysis can determine not only the presence of excess minerals in the urine but also which type of crystals are forming

, Feline Urinary Crystals: Signs, Symptoms, and Solutions, The Comforted Kitty

As urinary crystals are frequently an indicator of another illness, your veterinarian may request tests to check blood sugar levels, hydration, and liver function.

The treatment that your veterinarian recommends will depend on which type of stones are detected, how large they are, and the patient’s pain level. When caught early, many of these crystals can be dissolved by changing their diet. Prescription foods designed to control the urinary pH levels may be recommended to both dissolve crystals that have already formed and prevent new stones from forming. Stones that are too large, dense, or numerous to dissolve may need to be removed by mechanical means. This can include:

  • Cystotomy—The surgical removal of the mineral formation. This is typically a straightforward incision through the cat’s belly removing stone from the bladder by surgery. Recovery from this procedure is typically two to four weeks
  • Cystoscopy—Female cats with small stones may elect to use cystoscopy to remove the stones. Cystoscopy involves threading an extremely narrow tube through the urethra and into the bladder. This scope can also be used to remove stones that have become lodged in the urethra. This isn’t usually a viable way to remove stones from male cats because the urethra is too narrow. Recovery from this procedure is usually between one and seven days.
  • Voiding Urohydropropulsion—This means of removing urinary crystals requires a shorter sedation period than the others. The patient’s bladder is filled with fluid until it is distended and then manually expelled. While less invasive than cystoscopy or cystotomy, there is still a risk of inducing a urinary tract infection or causing trauma to the urethra. Patients usually recover from this procedure within just a day or two.

At Home Care

Cats who have developed urinary crystals in the past are more likely to develop them again in the future. To help prevent further episodes, cats who have experienced this condition usually continue with the new prescription diet. In most cases, cats who have previously developed urinary crystals are also required to avoid treats or supplements that are not part of the prescription diet.

, Feline Urinary Crystals: Signs, Symptoms, and Solutions, The Comforted Kitty

Hydration is especially important for these cats. Adding more water bowls throughout the house, investing in a fountain or waterfall-style watering bowl, or even just leaving the faucet running once in a while may help to encourage your cat to drink more water. You can also increase your cat’s fluid intake by switching to wet food instead of dry. Some cats may also have antibiotics prescribed to prevent infection and anti-inflammatory medications recommended to reduce pain and swelling.

When treated promptly, cats usually recover completely from this condition, but it is prone to reoccurring. Delaying treatment can lead to serious and sometimes permanent damage to your cat. If your cat is showing signs that urinary crystals may have formed, it’s imperative to seek treatment as quickly as possible.



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