Urinary Incontinence

Urinary incontinence is a common problem in dogs and can be frustrating for owners and for veterinarians trying to treat the condition. Urinary incontinence is defined as the loss of voluntary control over the retention and expulsion of urine. Simply stated dogs leak urine when the pressure in the bladder exceeds the urethral pressure. 

Incontinence is recognized most often in the middle aged, spayed female medium to large breed dogs. In fact 20% of female dogs will have some degree of urinary incontinence. Most of these affected dogs can urinate normally but tend to leak urine while sleeping or in a recumbent position. The majority of dogs that have incontinence have problems with the competence of the neck of the bladder and the tone in the urethra. This is not to be confused with young dogs that leak urine related to ectopic ureters. Interestingly dogs that are spayed before the first heat cycle have a much lower incidence of urinary incontinence. 

The diagnosis of urinary incontinence, defined as a weakness in the bladder neck and urethra, is obtained by ruling out other possible causes. It is critical to evaluate a urine sample for urinary track infection, as an infection could easily mimic incontinence. Also the lower urinary tract and reproductive system should be checked for bladder stones, polyps, tumors, and other anatomic abnormalities that might cause incontinence. This evaluation can usually be completed with a thorough physical exam, along with radiology, and or ultrasound of the areas. Definitive diagnosis can be made by a specialist by actually measuring specific pressures with in the urethra. 

The treatment of urinary incontinence is always medical first. The most common therapy is oral medication that stimulates the urethra to have more tone. This increase in tone offers more resistance to the outward flow of urine. Drugs like phenylpropanolamine are 74% to 92% effective in controlling incontinence. Estrogen is the other medication that has shown to be effective for this condition. It works by increasing the receptors in the urethra so that the urethra is more responsive to signals that cause increased tone. In refractory cases these two drugs can be used in combination. 

In cases that do not respond to medical therapy, there are a number of surgical options. Although these options can be effective, most are very invasive. Recently a new technique has become available that is minimally invasive and approximately 70% effective with out medication. 

This new technique reflects the ongoing advancement of veterinary medicine and surgery. In this technique medical grade collagen is injected endoscopically into the urethra to thicken it and give more control of the outward flow of urine. The collagen is injected in 3 sites to form a ring that narrows the inside of the urethra. The effects are immediate, and the collagen injections have been shown to last several years. 

Urinary incontinence is a common problem; therefore it is nice to know that much research is focused on the subject. This research leads to a deeper understanding of the problem as well as new treatment options.