Urodynamic testing evaluates how the bladder, sphincters, and urethra function to store and release urine. It provides information on the lower urinary tract’s ability to hold and empty urine, and coordinate muscle activity. This series of tests helps healthcare providers understand the underlying causes of urinary symptoms and develop effective treatment plans.
Why Urodynamic Testing is Performed
Doctors recommend urodynamic testing to pinpoint the reasons behind problematic urinary symptoms. It helps diagnose conditions like urinary incontinence (involuntary urine leakage), frequent urination, sudden urges (overactive bladder), or difficulty emptying the bladder. The tests also investigate weak or intermittent urine flow, or recurrent urinary tract infections. They determine if bladder muscles are weak, if there’s a blockage, or if nerves controlling bladder function are not working properly. For instance, a slow flow might indicate an enlarged prostate or a weak bladder muscle.
How to Prepare
Preparation involves a few steps for accurate results. Patients should arrive with a comfortably full bladder, as the initial test requires urination. Normal fluid intake is encouraged, but excessive intake before the test is unnecessary. Your provider may instruct you to temporarily stop certain bladder medications, especially those that relax the bladder, a few days (typically 2 to 7 days) before the test. This allows for an accurate assessment of your bladder’s natural function. Discuss all current medications with your provider to clarify which ones, if any, should be paused. You might also complete a bladder diary for a few days, documenting urinary habits.
What Happens During the Test
Urodynamic testing typically begins with uroflowmetry, where you will be asked to urinate into a specialized device resembling a toilet. This machine measures the volume of urine, the speed of the flow, and how long it takes to empty your bladder. It generates a graph that helps identify any abnormalities in your urine flow pattern, such as a weak stream or an obstruction. This initial step provides insight into your bladder’s emptying ability.
Following uroflowmetry, a small, flexible catheter is gently inserted into your urethra and guided into the bladder. A second, similar catheter may be placed into the rectum or vagina to measure abdominal pressure. These thin catheters connect to pressure-measuring devices, monitoring bladder and abdominal pressures throughout the test. While catheter insertion might cause slight discomfort, the test is generally not painful.
The cystometric study begins as your bladder is slowly filled with sterile water or saline through the catheter. As it fills, you report sensations like the first urge to urinate, fullness, and a strong need to empty your bladder. Pressures inside your bladder and abdomen are continuously recorded, assessing bladder capacity and muscle response to filling. You may also be asked to cough or strain to check for urine leakage under pressure, a common symptom of stress incontinence.
After filling, a pressure flow study is performed. You urinate with catheters in place, allowing simultaneous measurement of bladder pressure and urine flow rate during voiding. This helps determine if your bladder muscle can generate enough force to empty effectively and if there is any urethral obstruction.
Electromyography (EMG) may be included if nerve or muscle damage is suspected. Small sensors placed near the urethra or rectum record the electrical activity of pelvic floor muscles. This assesses coordination between the bladder and pelvic floor muscles during filling and emptying. The entire session typically lasts 30 minutes to an hour, varying by specific tests and circumstances.
Interpreting Your Results
Once complete, the collected data provides a comprehensive picture of your lower urinary tract function. Information includes bladder capacity, pressures during filling and emptying, and urine flow rate and pattern. Results can indicate difficulty storing or emptying urine, or issues with muscle and nerve coordination. While some immediate feedback, like uroflowmetry results, may be available, full interpretation requires careful analysis. Your doctor will typically schedule a follow-up appointment, often within one to two weeks, to discuss findings. This discussion clarifies the diagnosis and guides appropriate treatment options.