Sometimes underlying medical conditions interfere with urine’s antibacterial properties and the body’s ability to fight infection. The result is often a bladder infection. Bladder infections in dogs are similar to bladder infections in women—both cause painful urination, blood in the urine, or an urgent need to urinate when there’s little urine in the bladder.
Risk factors and detection
Any medical condition that interferes with the body’s defense mechanisms can contribute to a bladder infection. For example, diabetes causes excess sugar in the urine, which creates an ideal breeding ground for bacteria. Cushing’s syndrome, also known as hyperadrenocorticism, or corticosteroid therapy with prednisone can lower the body’s defenses as well, making your dog susceptible to infections.
Kidney disease can dilute urine, which reduces its antibacterial properties. Bladder stones or tumors can affect the bladder’s mucosa, or inner lining, making it easier for bacteria to attach and multiply. Neurologic problems that prevent the bladder from completely emptying (after spinal disk injuries, for example) and incontinence can cause similar problems.
Middle-aged to older dogs, who are more likely to have the problems mentioned above, show a higher incidence of infection. Females develop bladder infections more often than males because the tube exiting the bladder, called the urethra, is shorter in females. Also, a sheath protects the penis, making it harder for bacteria to migrate up a male’s long urethra.
Signs of bladder infection include:
- housesoiling
- bloody, cloudy, or foul-smelling urine
- licking the genital area more than usual urinating smaller amounts and more frequently than normal
- straining to urinate, or worst case, inability to pass urine.
Most bladder infections aren’t emergencies. If your dog is eating and drinking normally and is energetic, you can schedule an appointment with your veterinarian within the next 24 hours. But if you suspect something more serious, such as blockage or kidney infection, get help right away.
Symptoms of a more serious problem might include:
- lack of energy and appetite
- vomiting
- inability to pass urine
- pain
- fever
The veterinarian will examine your dog thoroughly, checking the bladder for tenderness, stones, or abnormal firmness. He or she will take a urine sample to test for bacteria, blood, white blood cells, protein, sugar, or any other abnormalities. The doctor also will check the urine’s concentration and pH.
Your veterinarian will collect a urine sample in one of three ways:
1. Free catch while urinating. In other words, your veterinarian holds a container under the urine stream. This is the least sterile method and may accidentally introduce bacteria into the sample.
2. Catheterization. The veterinarian passes a small catheter up the urethra to collect urine. While this method is more sterile than a free catch, normal bacteria in the end of the urethra or around the foreskin or vulva may contaminate the sample.
3. Cystocentesis. Your veterinarian passes a fine needle through the abdominal wall directly into the bladder. It sounds uncomfortable, but it’s no worse than getting vaccinations.
If this is your dog’s first bout with a bladder infection, your veterinarian likely won’t recommend additional testing. But if your dog suffers from recurrent infections; is obstructed; shows signs of a kidney infection, such as pain or fever; or if your veterinarian suspects additional conditions; he or she may perform urine cultures, X-rays, an ultrasound, and blood tests to make an accurate diagnosis.
Prevention and treatment
To prevent infection, work with your veterinarian to eliminate the predisposing factors mentioned above.
If your veterinarian diagnoses diabetes, your dog probably will require insulin. You can sometimes dissolve bladder stones with specially formulated diets, but they may require surgical removal. Tumors also require surgery—if they’re removable.
Uncomplicated, first-time bladder infections usually respond to a 14-day antibiotic treatment. Your veterinarian may culture your dog’s urine to discover what bacteria are growing and select the most suitable antibiotic.
If your dog has recurrent infections and no treatable underlying condition, your veterinarian may prescribe low-dose, long-term antibiotic therapy. This is usually administered at bedtime after your dog urinates to ensure the antibiotic stays in her body for a long time.
Prognosis
Prognosis is good for dogs with uncomplicated or even recurrent bladder infections. However, talk to your veterinarian about any prognosis involving a more serious underlying disease, such as diabetes, adrenal disorders, or cancer.
