Bladder Stones in Dogs

What are bladder stones?

Bladder stones (uroliths or cystic calculi) are rock-like formations of minerals that develop in the urinary bladder. There may be a large, single stone or a collection of stones that range in size from sand-like grains to gravel. It is common for a mixture of both small and large stones to be present.{{more}}

What other kinds of stones are there?

Gall stones form in the gall bladder and contain bile salts. Kidney stones are mineralized formations that develop in the kidney. Neither of these are directly related to bladder stones. Even though the kidneys and the urinary bladder are both part of the urinary system, the development of kidney stones is not usually linked to the development of bladder stones. All stones form as a result of disease or inflammation in the affected structure.

What are the clinical signs of bladder stones?

The most common signs that a dog has bladder stones are hematuria (blood in the urine) and dysuria (straining to urinate). Hematuria occurs because the stones rub against the bladder wall, irritating and damaging the tissue and causing bleeding. Dysuria may result from inflammation and swelling of the bladder walls or the urethra, from muscle spasms, or due to a physical obstruction to urine flow caused by the presence of the stones. Veterinarians assume that the condition is painful, because people with bladder stones experience pain, and because many clients remark about how much better and more active their dog becomes following surgical removal of bladder stones.

Large stones may act almost like a valve or stopcock, causing an intermittent or partial obstruction at the neck of the bladder, the point where the bladder attaches to the urethra. Small stones may flow with the urine into the urethra, where they can become lodged and cause an obstruction. If an obstruction occurs, the bladder cannot be emptied fully. This is extremely painful, especially when pressure is applied to the abdomen. If the obstruction is not relieved, the bladder may rupture. A complete obstruction is potentially life threatening and requires immediate emergency treatment.

How quickly can bladder stones form?

Bladder stones can develop in a period of weeks to months. Speed of growth will usually depend on the quantity of crystalline material present and the degree of infection present. Although it may take months for a large stone to grow, some sizeable stones have been documented to form in as little as two weeks.

How are bladder stones diagnosed?

The symptoms of bladder stones are similar to those of an uncomplicated bladder infection or cystitis. Most dogs that have a bladder infection do not have bladder stones. Therefore, we do not conclude that a dog has bladder stones based only on these common clinical signs.

Some bladder stones can be palpated (felt with the fingers) through the abdominal wall. However, failure to palpate them does not rule them out. Some stones are too small to be felt in this manner, or the bladder may be too inflamed and painful to allow palpation.

Most bladder stones are visible on radiographs (x-rays) or an ultrasonic bladder examination. These diagnostic imaging techniques are generally performed on dogs that show signs of abdominal pain or have recurrent episodes of cystitis.

How are bladder stones treated?

There are three options for treatment. The stones can be removed by cystotomy, or surgically opening the bladder. These dogs usually make a rapid post-operative recovery. Dogs with a complete urethral obstruction require immediate life-saving surgery. Surgery may not be the best option for patients that have other health concerns.

The second option is to attempt to dissolve the bladder stones with a special dissolution diet. This avoids surgery and can be a very good choice for some dogs. However, it has some disadvantages:

o It is not successful for all types of stones. Stone analysis is necessary to determine if it is the type of stone that can be successfully dissolved. This may not be possible in all cases.

o It is slow. It may take several weeks or a few months to dissolve a large stone so the dog may continue to have hematuria, dysuria, and recurrent infections during that time. The risk of urethral obstruction remains high during this period.

o Not all dogs will eat the special diet. These diets will not work unless they are fed exclusively.

I performed a cystotomy to surgically remove these two Stones from the bladder of a Poodle some years ago.

For further information, contact: Dr Collin Boyle
Unique Animal Care Co. Ltd. Tel: 456 4981
Website: www.uniqueanimalcare.com