Tumor or cystitis?

Dr. Marie replied:

I'm sorry to hear the bad news about Smokey.

I'll comment on what you have written and hopefully I can help in understanding Smokey's situation a little better.

There are only a few things that can cause blood in the urine of a cat. The most common is a condition called interstitial cystitis. We don't know what causes interstitial cystitis. Cats that have it have bleeding from the bladder wall but no signs of infections or stones or crystals. An infection can cause blood, but there would be other obvious findings on the urinalysis that would tell us if there was an infection. Crystals or bladder stones can cause bleeding but again, should show up on tests well. A tumor can cause bleeding because it can make the bladder wall very irritated and it can bleed periodically. The only other thing that I can think of that would cause blood in the urine would be if there was a clotting problem (such as in an animal that ate rat poison), but this is very unlikely in your situation.

There is not a whole lot that we can diagnose from a bladder xray other than stones. Most bladder stones are very easy to see on xray. But, if there is a tumor then it is pretty rare that you can see something on xray. Similarly, there is not much that could be determined by blood work when we are looking for bladder issues. There is no blood test for cancers (although I have heard of some promising research that may allow us to find cancer markers in the blood, but this is not available right now.)

An ultrasound is very difficult to interpret. Even as a vet, when I first started looking at ultrasound photos I had a hard time seeing what was going on. A few years ago I took some courses on interpreting ultrasounds. One of the easiest parts of the body to ultrasound for me is the bladder. A bladder stone is very easy to see. A bladder tumor is usually relatively easy to diagnose, but you can't diagnose one with 100% accuracy.

What you see when you look at the bladder on an ultrasound is that the wall of the bladder is a certain density. The fluid inside of the bladder is a different density. You can follow the wall and look at it from every angle to see if the wall is thickened in any spot. If the wall seems to be very thickened in one particular area or if there is the same type of density as the wall that extends from the wall and into the bladder then this is very suspicious for a tumor. The most common area for a tumor of the bladder is the trigone which is the part where the bladder empties into the urethra. But, they can appear anywhere in the bladder.

I wouldn't say that bladder tumors are rare. I have seen many of them. I don't see them often, but I may see a couple of them a year.

Now, let's address the diagnosis of cystitis. There really isn't a conclusive test for cystitis. But, if we do a urinalysis and all we see is blood with no evidence of crystals or infection then cystitis is extremely likely. So, I can see why Smokey initially had this diagnosis.

At this point, if there hasn't been blood for 3 weeks then there are two possibilities. The first is that there is a tumor there which is no longer bleeding as tumors can just go through periods where they are not as inflamed. The second is that this could indeed be cystitis. Cats with intersitial cystitis can have symptoms that come and go.

So, how do we tell the difference? Unfortunately there are only two ways to say with more accuracy if this is a tumor. One would be to have an MRI done but this is very expensive. The second would be to have surgery done to open up the bladder. This does not make sense to do. There is a small chance that surgery could be done to remove a tumor, but usually if there is a tumor in the bladder wall it is not one that can be cured by surgery.

There are a few factors that make me think this is more likely to be tumor than cystitis. The first is Smokey's age. Usually cats who get interstitial cystitis struggle with it throughout their life. It would be unusual to get a first bout of it at 17 years of age. The other factor to consider is the vet's findings. If the vet feels that the bladder feels thickened and they really do feel like there is evidence on the ultrasound that supports a tumor then this really does add up to bad news.

But, what do you do? If Smokey is doing well, you can continue to do nothing. It may be a tumor that just bleeds from time to time. Eventually if it gets to the point where it is bothering him and it can't be fixed medically then the hard decision of euthanasia may need to be made. You may also want to talk to your vet about trying Smokey on Metacam. This is an arthritis drug that sometimes can help to reduce the size of bladder tumors.

It really does sound like your vet is doing all of the same things that I would do.

Please let me know if you have more questions.


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Dr. Marie replied:

Good questions!

1. Sometimes we can see abnormal cancer cells in the urine when there is a tumor, but not always. The most common type of bladder tumor is a transitional cell carcinoma and these tumors can shed sheets of cells. But...not always. So, if they happened to get a urine sample where the tumor just happened to have shed some cells then yes, it could be seen. But other types of bladder tumors don't shed cells. Or, they may have gotten a sample when it just wasn't shedding.

2. Don't worry about the "side effects" related to Metacam. There is some concern with the injectable form where in rare cases it has caused serious problems. But the oral form is actually very safe. There is more information here on my thoughts on Metacam in cats. I don't have literature in front of me on what advances there have been on chemotherapy agents for bladder cancers, but if I remember, the last time I researched for a case there was no therapeutic agent that was able to cure any type of bladder cancer. A drug called Piroxicam is our best bet at slowing down the growth (if it is a transitional cell carcinoma). But Piroxicam is hard on the kidneys. Meloxicam (Metacam) is very similar and we believe that it can help with these types of tumors but no studies have been done.

3. No, I am not aware of any holistic treatments. You will likely read of some on the internet, but they are mostly scams. If there was something natural that worked for cancers, in particular bladder cancers, we would be using and recommending it.

4. No, not really. The bladder is pretty protected. I suppose that if a fall happened and the kidney was damaged you could see a temporary bout of blood in the urine, but then there would also be a number of other symptoms. Plus, the type of injury that would be able to cause a kidney to bleed would have to be catastrophic like being hit by a car or kicked severely. There would be other evidence such as severe bruising that would have to be present as well.

Dr. Marie replied:

Yes, a bladder thickening can be caused by chronic cystitis. It all depends on whether it was generalized (i.e. the whole bladder wall was thick) or localized to just one area. If there is just one area that is thick then this makes a tumor more likely.

I think I answered #2 in my first answer - infection, stones, crystals or a clotting problem could all cause the symptoms but would have other methods of being detected.