What is urodynamic testing?
Urodynamics test the function of the lower urinary tract, including the bladder, urethra and sphincters. The tests can help determine why there are leaks, blockages or weaknesses and confirm which is the right treatment to address the problem.
In a healthy lower tract, the bladder can comfortably hold around two cups of urine for two to five hours. The bladder is relaxed, and the sphincter muscles in the urethra clench so urine doesn’t leak out. If the muscles, including the pelvic floor, are strong, there won’t be any leaks when you laugh, cough or sneeze.
When the bladder signals to the brain that it needs emptying, messages are sent back that clench the bladder muscles and relax the sphincters, expelling the urine.
In many people, this isn’t what happens. They can be urinating too frequently, leaking, experiencing pain or struggling to control their bladder. To improve this situation, understanding why things aren’t working as they should, needs to be investigated.
When are urodynamic tests recommended?
Incontinence is a symptom of an underlying issue, such as a UTI or weak pelvic floor muscle. In the case of a UTI, the doctor tests a urine sample for the bacteria causing the infection and prescribes a course of antibiotics. If the issue is a weak pelvic floor, exercises to strengthen it will be the solution. However, not all incontinence issues are so easy to identify and treat. This is when urodynamic testing can help.
The testing is used to investigate what’s causing:
- A weak or intermittent (stopping and starting) urine stream
- Difficulty starting a urine stream
- Frequent urination
- Painful urination
- Leaking or an inability to ‘hold on’ when lifestyle changes such as losing weight and pelvic floor exercises have failed to improve incontinence
- Sudden and intense urges to urinate
- Feeling like your bladder isn’t emptying fully
- Reoccurring UTIs
Effective treatment can then be recommended based on what’s behind the symptoms.
What do the urodynamics test?
There are several types of tests.
Simple observations can note:
- The time it takes to start a urine stream
- The volume of urine produced
- The ability or inability to stop the urine stream
While more sophisticated tests record:
- Images of the bladder filling up and emptying
- The pressure inside the bladder
- Muscle and nerve activity
Different tests will be conducted, depending on what the doctor is looking to establish.
Uroflowmetry or uroflow test
This test is designed to measure the volume and speed of urine as it leaves the body. The person urinates in private while the specialist equipment measure volume (by weight), second by second. The outcome is a graph that shows how long it took to establish a flow, when the maximum flow was achieved and any fluctuations in flow strength.
This test is conducted to identify the extremity of any blockage or obstruction, often caused by an enlarged prostate or tumour.
Postvoid Residual Measurement
As the name suggests, this test measures the amount of urine left in the bladder after it’s been emptied. There are two ways this can be performed: with or a catheter.
- Ultrasound. After the person has emptied their bladder, an ultrasound is performed on the bladder and from the images, a trained technician can measure the quantity of residual urine.
- Catheter. After emptying the bladder, a catheter is inserted into the bladder under local anaesthetic, and the remaining urine is drained into a measuring device.
If 100ml or more is left behind, that indicates that the bladder isn’t completely emptying. This retained urine can cause reoccurring UTIs and urge incontinence.
This test measures the relationship between pressure build-up in the bladder and the messages sent to the brain to indicate when it’s time to urinate. It can also measure bladder capacity. The test starts by inserting a catheter and draining the bladder, then a smaller catheter with a pressure-measuring device is inserted. A second pressure-measuring catheter may be inserted into the rectum.
Warm water is slowly poured into the bladder via the catheter as the person is asked to indicate when the urge to urine begins. The technician will measure the volume and pressure throughout the procedure. In some cases, the person may be asked to cough to increase the pressure.
This test can be used to identify the Leak Point Pressure. This is the pressure point when the warm water is expelled, either due to an involuntary bladder contraction (associated with urge incontinence) or a weak pelvic floor muscle.
The test can also identify compromised bladder capacity that’s causing frequent urination.
A Pressure Flow Study can also be conducted. This measure the amount of pressure needed to urinate as well as the correlation between flow-rate and pressure. This test is usual for men with enlarged prostates.
This test uses special sensors place on the skin near the urethra and rectum to measure the muscle and nerve activity in and around the bladder and sphincter. Doctors prescribe this test when they suspect that muscle or nerve damage is causing continence issues. The machine attached to the sensors produces a pattern of activity which will indicate any abnormalities.
Video Urodynamic Tests
These are conducted using ultrasound or x-ray and capture the bladder as it’s filled with liquid from a catheter and them emptied. The type of liquid depends on which method is used; contrasting fluid to be visible on x-ray and warm water for an ultrasound. The video captures the shape and size of the bladder as it expands and contracts, allowing the doctor to observe any problems.
Preparing for a urodynamic test
There are not usually any special requirements to prepare for these types of procedures. It will depend on which test or tests you’re having, and you may be asked to arrive at your appointment with a full bladder.
Most tests are conducted in the specialist’s rooms, a clinic or hospital.
The insertion of catheters and the use of sensors may require some local anaesthetic, but that will be done at the clinic or hospital as part of the procedure.
While these processes may seem embarrassing to you, remember that the health professionals are conducting them all day, every day. They understand people’s concerns and do everything they can to help you relax and feel comfortable.
After urodynamic testing
You may feel some discomfort after the tests, especially if you’ve had a catheter inserted. For this, a warm, wet face washer pressed against the urethra opening may provide some relief, and if necessary, take paracetamol.
Make sure you drink plenty of water. Although all care is taken with hygiene when using catheters, germs can enter the urethra. Lots of water will ensure your urinating regularly and flushing out any bacteria. If you do develop signs of infection – painful urination, fever, nausea – contact your doctor immediately.
The results will be sent to your doctor for analysis and input into your treatment plan.
Asaleo Care makes no warranties or representations regarding the completeness or accuracy of the information. This information should be used only as a guide and should not be relied upon as a substitute for professional, medical or other health professional advice.
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