Bladder Infections in Dogs

Table of Contents

Overview | Causes | Symptoms & Diagnosis | Treatment | Q&A


"Bladder infections in dogs occur because the bladder is a favorable environment for bacterial growth. Pathogenic bacteria can ascend into the bladder through the urethra, which is the tube which guides urine to the outside of the body. Predisposing factors such as a urinary obstruction, an immune deficiency problem and altered urine concentration are factors needed for the growth of infectious agents such as bacteria. There is also a small possibility that viruses may infect a dog's bladder, thus bacteria are considered only a possible cause and not a definitive cause of dog bladder infections."


Typical symptoms of canine bladder infection include painful and frequent urination, a reduced volume of urine, and the passing of blood mixed with mucous at end of urine stream and generalized illness. In laboratory, the species of bacteria causing the problem cannot be always detected; urinalysis and detection of respective antibodies are enough for confirmation. Antibiotic therapy and supportive measures are part of specific treatment plan.

Causes of Bladder Infections in Dogs

Pathogenic bacteria are considered to be the only cause of bladder infections in dogs. Viruses may cause other renal (kidney) infections, but there is little evidence that a virus can cause a dog bladder infection. It is believed that a dog's bladder is an unfavorable environment for viral proteins.

Bacterial infections in a dog's bladder are also called, “Bacterial Cystitis”. A number of bacterial species such as Staphylococcus, Proteus, E.Coli, Streptococcus, Klebseilla, etc. can cause canine bladder infections. Studies show that it is impossible for pathogenic bacteria to pass through the renal cavity and cause dog bladder infections. In most cases, bacteria usually ascend from the urethra and infect the walls of the dog's urinary bladder, ending with severe inflammation and lesions.

Dog Bladder Infection Symptoms

In the case of dog urinary tract infection (UTI) and specifically urinary bladder infections, there are typical symptoms that indicate that infecton is the problem including straining while urinating, severe pain while passing urine through the urinary tract, and frequent urination with a low volume of urine.

Similarly, urinating in inappropriate places is another symptom of a dog urinary tract problem. These symptoms are also associated with lower urinary tract infections, bladder stones, and canine urinary tract cancers.

Specifically, symptoms such as the passing of blood mixed with mucous and pus represents the presence of an infectious problem in the urinary bladder. In the case of bacterial cystitis, blood and mucous would pass from the body at the end of the urine stream and can cause severe pain. Clinically, a diseased dog appears dull, uncomfortable and feels pain on abdominal palpation (touching). Anorexia (appetite loss), fever, weakness and aggressiveness are some other related signs.

Diagnosis of Canine Bladder Infections

Clinical symptoms and a veterinary examination can help with the diagnosis, but confirmation of a bacterial infection is made with laboratory testing. Laboratory studies do not always reveal the exact species of causative bacteria. Usually a detailed urinalysis and immune response detection is enough to confirm an infection in the bladder, e.g. detection of urine pH is helpful in detecting Staphylococcus and Proteus species if the urine appears alkaline, (5.5 – 9). Similarly, the concentration, consistency and level of different components in the urine indicate different species of bacteria.

Radiography on other hand can help in differentiating a dog bladder infection from other illnesses. For example, the possibility of dog bladder stones and canine cancers can be eliminated with an abdominal x-ray.

Treatment of Bladder Infections in Dogs

In most cases the exact species of bacteria cannot be confirmed in bladder infections, thus broad spectrum antibiotics which can kill a variety of bacteria are considered to be the treatment of choice. Similarly, based on the results of a urinalysis, high doses of therapeutics can be administered in order to completely eliminate the infectious agents.

There is some concern regarding using vigorous antibiotic therapy, since antibiotics can have side effects such as the elimination of helpful micro-flora in the bladder and possible sensitivity to the medications themselves.Therefore sensitivity tests should be performed prior to the administration of antibiotics. Amoxicillin, Cefadroxil and Ometoprim-sulfadimethoxine are some frequently used antibiotics for treatment of bladder infections in dogs. Depending upon the severity of the infection, these can be used for 2 weeks or more.

As a supportive therapy, symptoms can be treated with specific drugs, but general care is important. A diseased dog should be supplied with excess amounts of hygienic (clean) water. Foods containing high concentrations of minerals should be prohibited. Similarly, some natural remedies such as UTI-Free Formula can help regulate urinary tract physiology and can help to reduce the effects of vigorous antibiotic therapy, related to elimination of micro-flora in bladder.

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Merck Veterinary Manual (Merck & Co. 2008)