Stones in the urinary tract are as
common in dogs and cats as they are in people. Even though dogs and
cats do get kidney stones, it is bladder stones that causes them more
problems. The medical term for bladder stone is urolithiasis.
Typical symptoms include straining to urinate (stranguria), blood in the urine (hematuria) , or urinating small amounts frequently (pollakiuria). There might also be excess urination (polyuria), pain in the rear quarters, reluctance to jump or play, or even lethargy. Some pets can have bladder stones without any apparent symptoms.
A urinalysis is helpful in making a diagnosis. The pH of the urine, mineral content, and the presence of bacteria or crystals all provide valuable information.
One of the best methods to make a diagnosis is radiography. Many stones are radiopaque, which means they show up vividly on an x-ray. Some stones are radioulucent, and do not show up on a regular x-ray. These stones are diagnosed by injecting air, dye, or a combination of both, into the bladder to outline any suspected stone.
This is the side view of a dog with a very large radiopaque stone in its urinary bladder.
Ultrasound is a very precise method to diagnose stones in the urinary bladder. It is particularly helpful for radiolucent stones and anatomical defects of the bladder wall.
There are many different causes to bladder stones. Some are due to diet, others are due to abnormal metabolism by the liver, and in some the cause is unknown. The pH of the urine and the amount of bacteria present are predisposing factors.
This is a picture of the stone that was in the x-ray above.
Bladder stones can be treated medically if they are of a certain mineral composition called struvite. The urinalysis gives us an idea of the composition of the stone. A food called S/D can actually dissolve these stones in the bladder, and prevent the need for surgery.
Stones can also be removed by lithotropy just like in people. This procedure is performed at Purdue University on very select cases.
The surgical removal of a stone in the urinary bladder is called a cystotomy. It involves making an incision into the abdomen, exteriorizing the urinary bladder, removing the stone(s), and resuturing the bladder. The following surgeries demonstrate the removal of two different types of bladder stones.
This next section contains graphic pictures of actual surgical procedures performed at the hospital. If you don't want to see them, click here to pass up these pictures and learn about prevention.
An incision is made into the pets abdomen and the bladder is brought out through the opening. After the bladder is exteriorized two stay sutures are placed. The stay sutures hold the bladder in place while the surgery proceeds. They are much gentler than holding the bladder with instruments that might damage this delicate tissue.
This bladder is particularly thick, due to the large size of the stone and the chronic nature of the problem.
An incision is made in the bladder just big enough to gently squeeze the stone through. We want to make this incision as small as possible to minimize anesthetic time, decrease discomfort post-opertatively, and prevent a healing bladder from rupturing when it gets distended with urine.
The lining of the urinary bladder is examined, and cultures and biopsies are taken if necessary.
The bladder is gently flushed if necessary, and a urinary catheter is sometimes placed. This catheter will prevent the bladder from over distending and rupturing in the first day postoperatively.
It is critical that the bladder is sutured back together properly. This is especially important with an incision this large and with a bladder that has had a large stone irritating it for a long period of time. The sutures need to be placed strong enough to hold the bladder together, yet gentle enough to allow the irritated bladder to heal.
Some dogs have multiple small stones as opposed to one large one. How many stones do you see in this urinary bladder?
The small size of these stones allow a much smaller incision. The time it takes to suture this bladder is significantly less than the large stone above. The tradeoff is much more time is spent in removing these small stones.
Stones this small tend to locate at the junction of the bladder and urethra. Not all of them can be removed by reaching in with a hemostat and removing them. A urinary catheter needs to be placed and the stones are flushed up so they can be grabbed with the hemostat.
Here are the culprits-did you find all 17 on the x-ray?
Seven sutures were put in this urinary bladder to seal it. They will slowly dissolve over the course of several months.
Removal of the bladder stone is the first step in the process. The next and just as important step is the prevention of the stone's recurrence. Some of these stones will require a diet change only, while others might require long term medication. Some breeds are predisposed to forming stones in spite of what we do to prevent them. Our doctors will set up a specific protocol for your pet based on the breed and type of stone removed.
Long term follow up is important. Your pet will have to return periodically to recheck a urinalysis, culture the urine for bacteria, and x-ray the bladder. Many stones recur because owners forget the importance of long term prevention.