Snow Leopard

Snow Leopard
Snow Leopard cub (7 mos old) - Cape May County Zoo

Wednesday, August 10, 2011

The Value of Ultrasound

It's amazing what an radiograph (x-ray) will NOT show that an ultrasound will. 

Today we had a case that illustrates this point.

An 11 yr old pit bull mix had been showing signs of a urinary tract infection starting approximately 1 month ago. The signs included frequent urination and loss of house training. He had no other signs. The urinalysis run at that time showed signs of a mild infection. Another vet put him on a standard first line antibiotic. He didn't show any response to that.

 He was sent to me to do a radiograph. Anytime we have recurrent or non responsive urinary issues we need to rule out bladder (or sometimes kidney) stones. Bladder stones require surgery and antibiotics will NOT solve the problem. This dog's abdominal radiograph was essentially non-remarkable. We put him on a stronger antibiotic. After 4 or 5 days he was not only still having the same problem with NO improvement but now the owners saw swelling in his back end. 

They brought him back to me yesterday and we examined the area - which seemed to be a soft tissue swelling not associated with anything in particular. 

Since he was a neutered male, his prostate was not likely the problem of his increasingly difficult urinations but, of course, I confirmed this with a rectal exam. Neutered and un-neutered dogs can have prostatic cancers but un-neutered dogs frequently have benign prostatic enlargement that can start to clamp off the urethra and cause major problems. 

Male dog urinary anatomy

Side note: neuter your dog!

Anyhow, I also passed a urinary catheter to assess the if the patency (or opening) of the urethra through it's entire length. The catheter passed with little difficulty, however, it went in farther than usual until I got urine to start flowing and there were small blood clots in it that have never been seen in the urine samples we've seen from him.

I also palpated a mass like lesion behind where his bladder sits in his abdomen - again in un-neutered dogs this is frequently the prostate. Not in his case. I told them my primary concern was cancer - notably a bladder cancer called transitional cell carcinoma (TCC). This cancer often grows at the outlet of the bladder (called the trigone) and eventually the animal becomes obstructed. We needed to get him an ultrasound to truly know what was going on.

So today, my colleague did a complete abdominal ultrasound.

Another side note: Even though we are focused on a specific area, we always ultrasound the entire abdomen. Why? Well, you never know what else you will find. Why not? You are already there. It costs the client the same. It's not painful or invasive. I say this because in my own personal experience I received several ultrasounds that were focused on one "quadrant" of my abdomen which really - excuse me - pissed me off - since I know full well that pain in one area can be from another. NOT good medicine! That's another story though. 

What did we find on this dog? His bladder was pushed forward. There was a large mass extending from the trigone and beyond. His sub lumbar lymph nodes (under the spine) were enlarged, abnormal and pushing on his bladder. In a normal dog you don't even "see" these on ultrasound. He only had a very small portion of "normal" bladder remaining. And oh, his spleen had lesions too. It appeared he had cancer throughout his abdomen. 

This is not OUR dog but those rounded objects in the center of the screen represent TCC.

This is not surgically fixable, even temporarily. In fact, even when it's just involving the bladder it often isn't because of the location of where it typically grows. It does frequently respond to an NSAID called piroxicam. The problem is we don't know if this dog has that type of cancer, another type or even more than one. The owners will give it a try and we'll see how the dog does clinically. Ultimately though they are going to have to make a decision soon. 

A good article from DVM magazine on Transitional Cell Carcinoma


  1. Hi,
    I was wondering how you measure TCC mostly localized in the prostate in ultrasounds. Do you measure all of the prostate, including hypo and hyperechoic areas or only the hyperechoic mass entering the trigone? Thank you!

  2. Hi Laura,
    I don't perform the diagnostic ultrasounds at my practice however, I'd say that when my boss does this, she measures the entire prostate. It may be hard to distinguish the borders on an ultrasound so we can compare normal size to abnormal size in many organs.