Crystals in the Urine in Cats

Cats who present with crystalluria need to be seen by a veterinarian in order to properly identify the crystals and diagnose any underlying conditions that may be causing them to form.

The development of crystals in the urine, or crystalluria, occurs when normal minerals that float in the urine bind to each other. Crystalluria often occurs as part of another condition. The microscopic crystals have the appearance of fine sand. Though crystalluria isn't always indicative of an accompanying condition or illness, such as a urinary tract infection or kidney stones, the formation of crystals puts the cat at an increased risk of these problems. A urinary blockage due to crystals in the urine is an emergency, and the cat needs to see a veterinarian immediately.  

Though the main symptom of crystalluria is the appearance of fine crystals in freshly-expelled urine, other symptoms from accompanying conditions may also occur. Because crystals in the urine that are passed in the litter box may be missed by pet owners, other symptoms may help pet owners discover something is wrong with their cat. These symptoms may include:

• Blood in the urine
• Straining to urinate
• Passing only small amounts of urine
• Frequent licking of the genitalia
• Urinating outside of the litter box, such as on the bed or carpet
• Depression
• Irritation
• Passing no urine, which is a medical emergency. 

Since many of these signs can indicate a problem, it is best to have your cat seen right away if they are displaying any of them.  

Crystalluria may be caused by the following:

• Oversaturation of minerals in the urine
• High concentration of crystallogenic substances in urine
• Dehydration
• Off-balance urine pH that is too acidic or alkaline
• Urinary tract infection
• Breed disposition, such as Persian, Burmese or Himalayan
• Medications
• Radiology diagnostic agents, such as radiopaque contrast agents
• Improper diet

The veterinarian will ask for the cat's health history, which will include any recent symptoms of urinary problems. The veterinarian will examine the cat and look for any irritation in the genital area. Because crystalluria may indicate the presence of bladder or kidney stones, the veterinarian will also gently feel the cat's abdomen, feeling for the presence of any large stones.

A urinalysis is the best test in order to identify crystalluria. The four most common types of crystals, calcium oxalate, uric acid, struvite, and cystine, can be isolated and identified with a urinalysis. The urinalysis will also test the urine pH, look for the presence of any white blood cells, bacteria, and protein in the urine.

If the veterinarian wants to take a sterile urine sample, this is done with a procedure called cystocentesis. During cystocentesis, a needle will be inserted through the cat's skin into the bladder. The veterinarian will take a sample of the urine before withdrawing the needle. A sterile urine sample allows the veterinarian to look at the urine without any contamination from the cat's urethra or genitals.

An ultrasound and x-ray may also be performed. These tests will help identify any abnormalities in the bladder, kidneys or urinary tract and look for the presence of any larger stones that could pose a medical emergency.

Fluid Therapy

If the cat is severely dehydrated, it may be necessary for the veterinarian to give the cat fluids intravenously. If the cat is just mildly dehydrated, increasing fluids orally is essential. These extra fluids will help flush out the cat's bladder, improving its concentration. It's important that the cat is given fresh water several times a day as cats may reject water that is too old or has debris in it.

Modified Diet

Cats should be fed a diet that consists of both wet and dry food. The veterinarian may also place the cat on a prescription diet aimed at correcting the cat's pH levels. It is important to keep the cat well-hydrated to prevent additional crystals from forming.

Medications

Because crystals can irritate the cat's bladder and cause an infection, the cat may be prescribed an antibiotic in order to prevent an infection from occurring. Pain relievers may also be prescribed if the crystals are causing the cat significant pain.

The veterinarian will want to see the cat every three to six months in order to perform a urinalysis to ensure that crystals are no longer present in the urine and that the urine pH has returned to normal. Any other accompanying conditions, such as a urinary tract infection or bladder stones, will also need to be monitored. If symptoms don't improve or worsen, the cat should immediately be seen by a veterinarian in order to determine if stones have formed that may be stopping the flow of urine.