Monday, June 15, 2015

Bladder stones: A Technician's Perspective

Can you tell which cat has bladder stones?

In light of the numerous cases of bladder stones, crystals and inappropriate urination issues we have seen in the last month, I thought that I would share my own experience with bladder stones, in the hopes that others will take away the same lessons that I learned.

For over a decade, I shared my life with two lovely cats who were brother and sister. Mina, the sister, is still with me, but I lost Marley to lung cancer in 2013. Both cats came from a rescue group in East Lansing, siblings from a litter of hand-raised kittens whose mother had died when they were 10 days old. Both cats were fairly healthy during their younger years - Marley had a congenital cataract, Mina had some foul diarrhea. Marley had chronic skin allergies. Both cats went through a period of time when they had adverse vaccine reactions. Mina occasionally has bouts of bronchitis. Together, they
kept my hands full!

In September of 2009, I noticed that Marley had stopped squatting to urinate. I was annoyed by the habit, because he would stand in the litterbox and a big stream of urine would splatter out onto the floor in front of the box. I watched this go on for two weeks, because he didn't seem to be in pain - he didn't vocalize or strain when he urinated, he didn't seem to be going all that frequently - maybe 2-3 times daily. He didn't seem to be drinking more water than usual, and the urine wasn't bloody. I wondered if he had developed some arthritis in his hips - after all he was 9 years old at the time. I brought him in to work with me and after a thorough exam, we took hip x-rays. Dr. Brooks looked at the x-ray and said, "Well, his hips are fine, but he has bladder stones." I thought she was teasing me. I couldn't believe it. I looked for myself. Sure enough, there they were - 7 stones (I would share the x-ray, but it is in attic storage, now, and I don't like attics). A few weeks later, I scheduled him for surgery - I forget now, why I waited. It might have been a busy surgery schedule. I might have been saving up money. Anyway, it was a dumb idea to wait, because I was on pins and needles the whole time, worrying that he might become obstructed with a stone. This was a little silly, not because it wasn't possible, but because it takes weeks to months for stones to form, so he could have become obstructed at any time prior to his diagnosis, and I had not been worried, before. Worrying wasn't going to help him. Surgery was the only option.

Calcium oxalate stones
Surgery went smoothly, and 7 large stones (and two smaller stones that were not visible on the x-ray) were removed. We sent off the stones for analysis at the Minnesota Urolith Center and the report stated that they were 70% Calcium Oxalate Monohydrate and 30% Ammonium Acid Urate stones. After surgery, Marley didn't like using the clay litter we use here in the hospital, so he urinated bloody urine on the floor and towel until we switched him back to scoopable clumping litter. At home, he resumed urinating in the box normally, squatting like a good boy.

After that, he switched to a canned stone-prevention diet. Calcium oxalate stones do not dissolve with a dietary change, but they can be prevented from re-forming in many cases. Marley had bladder radiographs and urine rechecks every 6 months until 2012. I had a baby and went on maternity leave around the time that he was due for a recheck. In retrospect, I should have brought him in for a recheck early, but I was caught up in my own medical issues at the end of my pregnancy, and I figured a few months' delay was not that important.

But it was. In May of 2012, four months after the birth of my daughter, I was scheduling Marley for a
One large stone that required surgery to remove, and the many smaller stones we expressed.
repeat cystotomy. He had a bladder full of stones again. They were smaller, this time, but one stone was large enough that it could not be expressed. Marley recovered well from his second cystotomy and continued to do well until July 2013, when cancer took its toll.

Shortly after I lost Marley, his biological sister, Mina, started vomiting. She has had occasional bouts of acute vomiting, and was empirically
diagnosed with inflammatory bowel disease in 2005. In August 2012, she had a bout of vomiting that lasted about a week, and I brought her in for abdominal x-rays. At that time, she was having no issues urinating in the litterbox. She did not have any intestinal abnormalities, but there was a shadow in her bladder, which turned out to be a "puddle" of small stones. Fortunately, since she is a female, we were able to express all the small stones out of her bladder, and surgery was avoided. We sent in the stones to the Minnesota Urolith Center and they were 100% Calcium Oxalate stones. She has also been eating a crystal prevention diet and so far, she has had no further sign of stones on any of her followup xrays or urine samples.

If I had taken my own advice, many years ago, and fed canned food to my cats more often, I might

Sometimes, a lot of small stones look like one large stone
never have had to deal with this issue, as their urine might have been more dilute and less likely to form stones. I was very fortunate that neither of my cats decided to start urinating outside the litterbox due to discomfort - in fact, they are both very good examples of the fact that cats hide their problems from their owners. As a technician, I should be more attuned to signs and symptoms of illness, and I was unaware of the issues my own cats had. They are also a good testament to the importance of follow-up. Even if your cat seems fine after a treatment or procedure, it is important to follow-up on schedule. If I had brought Marley back 3 months earlier for a recheck, he might have been able to avoid the second cystotomy surgery. It may be that Mina will be one of the lucky few cats that never re-forms stones after a cystotomy, but you can be sure that I will continue to check her every 6 months!
Mina would rather nap than have a bladder recheck