Urinary tract infections are among the most common health issues seen in dogs. Is your dog suddenly peeing everywhere and drinking lots of water? Perhaps his urine has a strong odor or even contains blood. It could be a UTI.
Urinary Tract Infection
Your dog's urinary tract is comprised of the kidneys, ureters, bladder, and urethra. The kidneys make urine, which is then passed through small tubes called ureters that lead to the bladder. The urethra is the small tube that allows urine to exit the bladder and the body. A urinary tract infection is a bacterial infection in one or more of these areas of the urinary system.
When UTIs occur in dogs, they are most often bacterial bladder infections that may involve the urethra. Instead of saying "urinary tract infection," a more accurate term is "lower urinary tract infection." Less common are infections of the ureters and kidneys. A kidney infection is referred to as "pyelonephritis" and typically causes more major symptoms than the average lower UTI.
Cystitis is a term that means "inflammation of the bladder." Cystitis will accompany most lower UTIs, but can also be a stand-alone problem.
Signs of Urinary Tract Infections
Not all dogs with UTIs will show signs of illness, but most will display one or more of the following:
- Increased thirst
- Frequent urination
- Inappropriate urination (house soiling)
- Urinating small amounts at a time
- Straining to urinate
- Bloody urine
- Urine with strong odor
- Dark-colored and/or cloudy urine
- Painful urination
- Licking genitals more than usual
- Pain in abdomen
- Loss of appetite
The signs of UTI are similar to the signs of cystitis. Bloody urine is common when cystitis is caused by bladder stones. A true lower urinary tract infection may not actually be the problem. In addition, the above signs may be related to pyelonephritis or another serious condition. If vomiting and/or diarrhea are also noted, there may be something more serious going on.
Whether your pet has a UTI, cystitis, pyelonephritis, or another health issue, you should not delay. Contact your vet if your pet shows any of the above signs.
Urinary Tract Infection Causes
In normal, healthy bodies, the bladder is sterile (and, therefore, the urine is sterile, too). This means no bacteria is present. When a lower UTI occurs, it means bacteria is present in the bladder.
The urethra leads out of the body to the genitals, an area that typically contains a lot of bacteria. It is thought that this bacteria can make its way up the urethra and into the bladder. In most cases, the body's normal defenses can prevent an infection from occurring. Some dogs are more prone to lower UTIs. In some cases, it is a genetic predisposition. Some dogs can have anatomical/structural abnormalities in the lower urinary tract leaving them prone to UTIs. One common cause of lower UTI is the presence of bladder stones. In general, female dogs are more prone to lower UTIs than male dogs.
Note that diabetic dogs are more prone to UTIs because of the presence of glucose in the urine. The signs of urinary tract infections might actually be caused by a behavioral problem. It is important to see your vet and rule out a health issue first.
Diagnosing Urinary Tract Infections
Your vet will first discuss your dog's history and complete a physical exam. Then, a urine sample will be collected. The ideal way to collect a clean using sample is via cystocentesis, which involves the insertion of a needle through the abdomen into the bladder. It's actually not as bad as it sounds. Most dogs tolerate this as easily as a blood draw (or easier even). Often, the vet will start with a "free catch" or "voided" sample. The sample is collected mid-stream while the dog is urinating into a clean container.
These samples may be less than perfect because of the likely presence of bacteria on the genitals, but the mid-stream collection is usually helpful in minimizing the bacteria. Worst case scenario, urine can be collected from the table or floor if the dog has had an accident. These samples are not ideal because of the bacteria likely to be on these surfaces.
Most vets will first order a urinalysis to either be performed in-house or at an outside lab. The urine will be tested for various components including blood, protein and more. It will be examined microscopically for the presence of certain cells, bacteria, crystals and more. The results are consistent with a UTI when a marked amount of bacteria and white blood cells are seen. Cystitis can be confirmed by the presence of blood and some other cells. Crystals may indicate the presence of bladder stones (though not always).
Your vet may also order a urine culture and sensitivity. The sample will be sent to a lab and put onto a special plate. The lab will attempt to grow bacteria from the urine sample. If a bacteria is isolated, the lab will determine which antibiotics are most effective at killing the bacteria. This will allow your vet to be certain your dog is on the right antibiotic.
Note that abdominal radiographs (x-rays) or ultrasound will be recommended if the vet suspects bladder stones. It is important to detect bladder stones as soon as possible, as they will cause ongoing bladder issues and can even lead to obstruction.
Urinary Tract Infection Treatments
The general treatment for a UTI is a course of antibiotics. When a vet feels cystitis is also present, your dog may also be treated with an anti-inflammatory drug, which will help ease discomfort. It is important to use the medications as directed and finish the full course to treatment. Your vet may also recommend a repeat urinalysis and/or urine culture after antibiotics are completed. This is to confirm that the infection is truly gone.
In some cases, a veterinary therapeutic diet is recommended to help treat your dog's urinary tract issues. This is especially common when crystals and/or stones are present.
If UTI and/or cystitis symptoms persist despite treatment, your vet might recommend further diagnostics, such as radiographs or ultrasound. It is important that you about your dog's ongoing signs.