At the Animal Hospital at Thorndale, we do not like to see our patients in pain. Bladder infections are a common cause of pain during urination. They also cause a sense of urgency to go. Accidents in the house in a previously house trained dog warrant a trip to our hospital.
Bladder Infections
The term “cystitis” literally means inflammation of the urinary bladder. This term is rather general and applies to any disease that inflames the urinary bladder.
Causes of Cystitis
The most common cause of cystitis in dogs is an infection due to bacteria. However, other common causes include bladder stones, tumors or polyps in the bladder, and diverticula, or an out pouching in the bladder wall.
Clinical Signs
The most common signs seen by most owners is hematuria (blood in the urine) and straining to urinate. Many dogs with cystitis have discomfort when urinating; they will spend several minutes passing only a small amount of urine, and they may urinate more frequently than normal.
The signs will be determined by the specific cause of cystitis. Bacterial infections usually cause hematuria and dysuria (straining to urinate.) Bladder stones are often very rough; they cause irritation as they rub against the bladder wall which creates hematuria and dysuria. Tumors or polyps are usually not highly irritating to the dog’s bladder, but they can cause bleeding and mild straining to urinate. If the tumor is obstructing the urine outflow tract, the dog will urinate in a small stream over a long time period. A diverticulum is a small pouch in the wall of the bladder that usually causes hematuria and dysuria secondary to the chronic bacterial infection that occurs. Bacteria often reside deep in the diverticulum and are nearly impossible to eliminate without surgery.
Diagnosis
A history of hematuria, dysuria, and increased frequency of urination is strong evidence of some form of cystitis. When these are seen, several tests are appropriate.
The first group of tests includes urinalysis, urine culture, and bladder palpation (feeling with the fingers). A urinalysis consists of several tests to detect abnormalities in the urine, such as glucose and blood. It also includes a microscopic evaluation of the cells in the urine These are generally adequate to confirm cystitis, but they are usually not adequate to determine the exact cause. Many cystitis patients are treated with a course of antibiotics commonly effective against the major groups of bacteria likely to be involved in a bladder infection. A urine culture determines if bacteria are truly present and what antibiotics are most likely to be effective in killing them. This is appropriate because most cases of cystitis are caused by bacteria that may be eliminated easily with appropriate antibiotics. Bladder palpation is the first “test” for bladder stones, since some are large enough to be felt by experienced fingers.
The Negative Culture, Recurrence, or Failure to Respond to Antibiotics
Dogs may fail to respond to antibiotics for a variety of reasons. About 20% of the time the culture will be negative for bacteria and stones cannot be felt. In some cases, the response to appropriate antibiotics is excellent, but the problem reoccurs shortly after the antibiotic treatment course is complete. In other cases, the dog continues to have signs despite being on appropriate antibiotics. When any of these things happen, it is important that more tests be performed so that a diagnosis can be achieved. Things that can cause any and all of these results are tumors, diverticula, and bladder stones.
Plain radiographs (X-rays) are taken to further evaluate the bladder because many stones can be seen with this technique. However, the mineral composition of other stones requires that special radiographs, using contrast materials, or ultrasound be utilized. Plain radiographs are usually not able to visualize bladder tumors, polyps, or diverticula. A plain radiograph can be made without sedation or anesthesia in a cooperative dog.
An ultrasound examination is very useful in evaluating the bladder and the kidneys. This technique uses sound waves to visualize stones and some tumors and polyps. It may also identify other abnormalities of the bladder wall, including wall thickening. It, too, can be performed without sedation or anesthesia in a cooperative dog.
Occasionally, contrast radiographs are taken when plain radiographs and an ultrasound examination do not render the diagnosis. The bladder is filled with a negative contrast material (usually air), a positive contrast material (a special radiographic dye), and then a little positive contrast material with a negative contrast material (double contrast study). A radiograph is taken each time. These three procedures permit visualization of otherwise unseen bladder stones, tumors and polyps, diverticula, and wall thickening. It is necessary to pass a catheter into the bladder and to distend it with the contrast materials; therefore, general anesthesia is required.
Not all causes of hematuria originate in the bladder.
Dogs showing other signs of illness, such as fever, poor appetite, or lethargy, should also be evaluated for systemic diseases and bleeding disorders that may be causing hematuria. For these dogs, a chemistry profile and complete blood count (CBC) should be performed. If a clotting problem is suspected, a bleeding profile is appropriate as well.
Another cause of blood in the urine is kidney disease. Urinalysis, radiographs, and ultrasound, as well as a complete blood count and chemistry can help evaluate the kidneys.
Treatment of Cystitis
Treatment depends on the cause. Bacterial infections are generally treated rather easily with antibiotics. Some bladder stones can be dissolved with special diets; others require surgical removal. A bladder diverticulum should be removed surgically. Benign bladder polyps can usually be surgically removed. Malignant bladder tumors are difficult to treat successfully. Pain relief medications, such as Piroxicam, have been shown to not only help with discomfort, but also to have some activity in shrinking transitional cell tumors in the bladder of dogs.