DEAR DOCTOR K:
I’m a 65-year-old woman with urinary incontinence. My doctor isn’t sure what’s causing it, so I need to have urodynamic testing. What information will this test give my doctor?
Urodynamic testing is a series of tests that evaluate your urinary system in action. A doctor may want to do these tests if the cause of your incontinence isn’t clear. Perhaps your symptoms point toward more than one type of incontinence. Testing is also recommended if standard treatments haven’t helped.
The urodynamic test is likely to include one or more of the following procedures:
- Uroflowmetry measures the amount of urine you produce and the rate of the flow. A slow flow might indicate an obstruction in the urethra or a weak bladder muscle.
- Post-void residual volume measures the amount of urine left in your bladder after you urinate. This is particularly valuable if you’ve had repeated urinary tract infections, if you have a neurological disorder, or if your doctor suspects a blockage is preventing your bladder from emptying properly.
- Cystometry monitors how pressure builds up in your bladder as it fills with urine, how much urine your bladder can hold and at what point you feel the urge to urinate. (See illustration below.)
Pressure test (Cystometry)
For men or women, a cystometry test measures the pressure in the bladder, urethra, and abdomen. A catheter in the bladder fills the bladder with fluid and measures pressure in centimeters of water. Another catheter, placed in the vagina for women or the rectum for men, reflects the pressure in the abdomen. Cystometry can reveal detrusor overactivity, stress incontinence from sphincter weakness, or weak pelvic floor muscles.
This test can reveal abnormal contractions or spasms of your bladder muscle; signs of stress incontinence; and evidence that your urethra is unable to close completely. If you have low urine flow, this test can show whether this is due to weak bladder contractions or a blockage.
- Electromyography (EMG) uses small electrode patches to help determine whether your nerves and muscles are working together to properly coordinate the activities of your bladder and urethra.
- Cystography is an X-ray test performed during cystometry or uroflowmetry. It can pinpoint the location of a blockage or reveal a urethra that doesn’t close tightly enough.
- Video-urodynamic study is a computerized test measuring urine flow and pressure in the bladder and rectum. It may provide useful information about your bladder and urethral function, especially if you have problems urinating.
Urodynamic testing can help your doctor pinpoint which of the many possible causes of urinary incontinence you may be suffering from — and thereby identify an effective treatment. Having said that, it also is true that the testing alone often is not sufficient to identify the cause of the incontinence. The medical history and physical examination performed by the doctor also are important.
So if your primary care doctor has not talked to you in detail about the problem, or done a physical examination related to the problem, be sure you have a medical history and physical examination by an incontinence specialist before any of this fancy testing is ordered. That will increase the likelihood you’ll get effective treatment.