What Are Struvite Crystals? My Cat Taught Me on Veterans Day


I associate Veterans Day with a veterinary emergency. Last year, having the day off work proved to be a blessing for my cat Miko, who I had to rush to the vet because he had a urinary-tract disorder known as struvite crystals. It was my first experience with it. Today, one year later, I share what I learned, including an interview with Miko’s vet, Dr. Craig Meredith, who works at West Seattle Animal Hospital.

The story begins with Miko behaving oddly.

He has always been a bit of a loner. He’s kind of a recluse and doesn’t seek attention very often. Occasionally he will climb onto my lap and perch there for a bit. I have to be careful not to pet him too much or he will bite me.

So when I heard him meowing outside my bedroom door in the middle of the night, I knew something was wrong. The next morning, he joined me in my morning rituals, something he usually does not do. He meowed a lot and licked his genital area frequently. He kept visiting the litter box but it didn’t seem like anything was coming out. I called the vet and was told to bring him in right away. Suspecting a urinary blockage, veterinary staff kept him overnight to run tests and provide treatment.

It turned out Miko had struvite crystals, which is fairly common for male cats. He was hospitalized for a few days. Since then I’ve had to feed him a special prescription diet and will for the rest of his life to prevent the crystals from reforming.

Me with Miko shortly after he came to live with us.  Photo by Zinnia Willingham.
I hold Miko shortly after I adopted him. Photo by Zinnia Willingham

It all happened fast, but I learned that it’s good to listen to your cats when they are trying to tell you something. I was grateful I’d had Veterans Day off so I could observe Miko’s behavior, because he was obviously telling me something was wrong. Had it been a typical workday, I might not have gotten Miko to the vet in time. After the ordeal, I asked the vet a lot of questions about crystals in an effort to understand why they form and how to prevent them. Here are excerpts from my interview with Dr. Craig Meredith.

Kezia Willingham: Tell me about struvite crystals.

Dr Meredith: Struvite crystals and feline lower urinary tract disease is a complicated syndrome with a whole bunch of different factors playing a role in the development of the disease. … Struvite is composed of magnesium, ammonium and phosphate in the urine. With the right conditions the minerals can come out of solution and form crystals. The pH of the urine and how dilute the urine is both play a role in whether the crystals can form. The odd thing about struvite crystals is that they can be a normal finding. It is not unusual to see crystals in cats without any symptoms. They become a problem in male cats when they combine with mucus to form a urethral plug that prevents the cat from urinating.

When a male cat comes into the clinic with a urinary obstruction, the first goal is to relieve the obstruction. This is a medical emergency. If left untreated the cat will quickly go into kidney failure and die.

Miko with baby Luna.  Photo by Kezia Willingham.
Miko with baby Luna. Photo by Kezia Willingham

Can the crystals be prevented?

Yes, but how we do it really depends on which cats are you are talking about. Cats that have a history of struvite crystals are usually managed with a prescription food. These foods are designed to maintain the proper pH and urine concentration in order to prevent crystal formation. Cats with no history of crystals may benefit from being maintained on a wet food diet. Wet food has a higher moisture concentration and may help prevent crystal formation by diluting the urine.

How long do the crystals take to develop?

Crystals can form very quickly. Given the right conditions they can form in minutes. Larger stones usually take one to two weeks to form.

Is surgery the only option to treat them?

No, surgery is usually the last resort. … In Miko’s case we placed a urinary catheter (which required anesthesia) but didn’t perform any surgery. Most cats require surgery only if they have large stones in their bladders that need to be physically removed or are unmanageable with medical and dietary changes. Occasionally I will see a cat that blocks over and over. Sometimes I will recommend a procedure called a perineal urethrostomy. This is surgical reconstruction of the urethra and genitals to create a larger opening to the urethra. I usually refer these cases to surgeons, as there is significant risk for complications.

Miko and my son Justin in a homemade cat tree a few years ago.  Photo by Kezia Willingham.
Miko and my son Justin in a homemade cat tree. Photo by Kezia Willingham

Are there foods that can prevent the crystals from becoming an issue?

Possibly. In healthy cats with no history of crystals, I usually recommend wet foods that have high levels of moisture to dilute the urine. Cats that have a history of crystal problems are usually maintained on a prescription diet.

Do female as well as male cats get them?

Yes, but crystals are a much larger problem for male cats because of their smaller urethras.

Miko in 2015.  Photo by Kezia Willingham.
Miko earlier this year. Photo by Kezia Willingham

After the crystals are removed, what is the prognosis for long-term health?

The prognosis is usually pretty good as long as there isn’t any significant kidney damage resulting from the obstruction. However, recurrence is very common. Maintaining the cat on the appropriate diet is important to preventing crystal recurrence.

Any tips for managing urinary crystals in multicat households?

Make sure that the cat is receiving the appropriate diet, and to try and reduce feline stress in the household. It is important to make sure that all cats have access to food and water in places where they aren’t being challenged by other cats. It is important to make sure there are enough litter boxes for all of the cats in the household. I usually recommend one [litter box] per cat plus one additional.


As another Veterans Day rolls around, I am again grateful to have time off to appreciate those I love most in life, and to share the importance of listening to your cat. Has your cat alerted you to a health problem or other concern? Tell us in the comments.

About Kezia Willingham: Also known as the Breadwinning Laundry Queen, Kezia lives with her family, which includes a pack of rescued cats and dogs, in Seattle. A former high school dropout, she has a master’s degree in social work and a bachelor’s degree in human development. Kezia works as the Health Coordinator for an urban Head Start program and writes on weekends. She is a member of the Cat Writer’s Association. You can follow her on Twitter.

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