A Primer on Bladder Infections In Dogs

A dog with a bladder infection is a dog at risk for bladder stones. 

A dog’s urinary bladder is a sac-like organ for storing urine. 

It is found within the abdomen in the area between the rear legs.  When the muscles in the dog’s bladder wall contract, the urine then flows through the urethra. The urethra is the narrow tube that carries the urine outside the body.  A ring or “donut” of muscle—sphincter—surrounds the urethra near the bladder. The sphincter closes off the flow of urine until it’s time to go.

A Primer on Bladder Infections In Dogs

How does it happen?

Normally, urine is sterile, which means that it doesn’t contain any bacteria or other microorganisms.

However, bacteria can sometimes travel up the urethra into the dog’s bladder, causing your dog to have a bladder infection.

What does it look like?

The infection leads to irritation, which causes the muscles in the bladder wall to spasm. That leads to the urge to urinate more often than usual.  

Dogs with a bladder infection typically strain to urinate frequently, often passing only a small amount of cloudy or bloody urine.  If your pet needs to urinate more frequently than usual or starts having accidents, these are signals to see your veterinarian for evaluation and treatment.

Bladder stones

In some bladder infections, minerals in the urine crystallize and form bladder stones, which can be as small as grains of sand or larger than marbles or small rocks.

A Primer on Bladder Infections In Dogs
X-ray of bladder stones. Image: Little Critters Vet

Bladder stones can also create areas where bacteria can hide from antibiotics, leading to long-term infections that are difficult to treat.

Your veterinarian may be able to feel stones by palpating the bladder (ie, feeling it through the abdominal wall), but an x-ray or ultrasound is usually needed for a definite diagnosis.

In some cases, the stones can be dissolved by feeding your pet a special diet that changes the mineral content of the urine.  In other cases, your pet may need surgery to remove the stones or treatment with sonic vibrations that “crushes” the stones.

Related articles:
What Causes Bladder Infections in Dogs?

Further reading:
Canine Bladder Infections

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