Acute Cystitis in Dogs

Acute cystitis is inflammation of the urinary bladder usually caused by a bacterial infection. Most cases of bacterial cystitis are "ascending," meaning that the offending bacteria arise from the dog's own intestinal tract and "ascend" to the bladder, beginning at the perineum (the skin around the anus) and proceeding to the urethra and ultimately the bladder. The vagina in female dogs and the prostate gland in male dogs are other potential sources of offending bacteria. Acute cystitis is more common in female dogs than in males.

Possible Causes

Stones. Some types of bladder stones can predispose to bacterial cystitis and infection of the bladder. Certain types of bacteria, Staph and Proteus, can lead to development of a specific type of bladder stone called "struvite."

Tumors of the bladder also may predispose to bacterial urinary tract infection.

Nervous system problems that prevent the animal from emptying the bladder completely also may predispose to development of urinary tract infection.

Some diseases (diabetes mellitus, "Cushing's disease") and medications (cortisone-like drugs that suppress the immune system, anti-cancer drugs), also may predispose to bacterial urinary tract infection.

What to Watch For

Blood in the urine

Straining to urinate

Increased frequency of urination

Diagnosis 

Diagnostic tests are needed to recognize acute cystitis and exclude other diseases. Tests may include:

Your veterinarian will obtain a complete medical history and perform a thorough physical examination including palpation of the abdomen to evaluate the bladder. The medical history will include questions about reproductive status (sexually intact or neutered) as well as questions about changes in water consumption and urinations, appetite, weight loss, previous illness, and previous medications.

Urinalysis to evaluate for the presence of white blood cells, red blood cells, and crystals. Microscopic observation of bacteria in the urine is a useful finding in a properly collected and handled urine specimen, but the absence of bacteria does not exclude the possibility of urinary tract infection. The finding of excessively alkaline urine (high pH) also increases suspicion for urinary tract infection.

Bacterial culture and sensitivity of urine is performed to identify the offending organism (usually E. coli, Proteus, Staph or Strep). Urine for culture must be obtained by cystocentesis (collection of urine by a sterile needle passed through the abdominal wall and into the bladder) or catheterization (collection of urine via a catheter passed by sterile technique through the urethra and into the bladder), to assure proper interpretation of results.

Treatment

The main treatment for acute bacterial cystitis is a 2 to 3 week course of antibiotics. Results of sensitivity testing may be used to choose the appropriate antibiotic. However, some antibiotics (penicillins) are secreted by the kidneys and achieve very high concentrations in urine. Such antibiotics can be effective for treatment of bacterial urinary tract infections even when sensitivity testing indicates otherwise. For this reason, your veterinarian may choose an antibiotic to treat a dog with his first urinary tract infection without performing urine culture and sensitivity testing.

A search for predisposing causes (e.g., bladder stones, nervous system abnormalities, bladder tumors, etc.) is warranted in dogs with recurrent episodes of bacterial urinary tract infection.

Home Care and Prevention

Administer as directed any medications prescribed by your veterinarian. The best time to give antibiotics is in the morning and evening. 

Urine culture should be performed 5 to 7 days after completion of the antibiotic course to ensure that urinary tract infection has been eliminated.

You should also provide unlimited access to fresh clean water and follow-up as directed with your veterinarian for physical examination and urinalysis. Additional diagnostic evaluation may be recommended to identify predisposing factors if your pet's response to treatment is incomplete.

It is difficult to prevent acute cystitis. Provide unlimited access to fresh clean water and provide your pet with frequent opportunities to urinate. If possible, avoid treatment with corticosteroids (cortisone-like drugs) that may predispose to development of infection.