Urodynamic study

About urodynamic study

Urodynamic study can help find what's causing urinary incontinence (involuntary leakage) or retention (difficulty in passing urine). It checks how your bladder, the muscle around the neck of your bladder (sphincter) and the tube through which urine flows out of the body (urethra) are working.

The purpose of urodynamic study is to find out whether your:

* symptoms are due to involuntary contractions (squeezing) of your bladder muscles
* bladder pressure is normal during filling and emptying
* bladder capacity is normal

What are the alternatives?

Your doctor may suggest alternative imaging tests, such as plain X-rays of the urinary system, CT (computed tomography) scan or renal ultrasound. Urodynamic study is usually only done if an obvious cause of incontinence or voiding problems isn't found.
Preparing for your procedure

Urodynamic study is usually done as an out-patient procedure. This means you have the test and go home the same day.

You may be asked to keep a record of how much you urinate (called a voiding diary) over three days. You will need to record what type of fluid you drink, when and how much, and the timing and volume of urine output each day. You will need to record when you feel urgency or leak urine. The hospital will give you detailed advice about how to complete a voiding diary beforehand. This diary helps your doctor better understand your bladder problem. You may also be asked to stop any current bladder medication for at least a week beforehand.

You can eat and drink as usual before having urodynamic study. You may be asked to come to your appointment with a full bladder.

At the hospital your nurse may check your heart rate and blood pressure, and test your urine for infection. If you have a urinary infection (known as a urinary tract infection, UTI) your doctor may decide not to proceed with the test and ask you to come back after the infection has cleared.

The procedure may involve X-rays to help your doctor confirm your diagnosis. A radiographer (a health professional trained to perform imaging procedures) usually operates the X-ray machine and produce images on film or in digital format.

You must tell your doctor or radiographer about any medicines you are taking and if you have any allergies, glaucoma or heart disease. If you are a woman of childbearing age, you must tell your doctor or radiographer if you could be pregnant. X-rays are safe for adults, but may harm your developing baby. If you're pregnant, your doctor will discuss alternatives to the procedure.

Your doctor will usually ask you to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ahead.
About the procedure

Urodynamic study usually takes 15 to 30 minutes.

You will need to remove your lower clothing and put on a hospital gown. You may need to lie back on a special X-ray table, which can be moved into different positions.

Fine tubes (catheters) with sensors attached to the tip are passed into your bladder through the urethra, and placed in your vagina or rectum. You doctor may apply a local anaesthetic gel around the entrance of your urethra beforehand to minimise any discomfort. You may feel the sensation of needing to pass urine as the catheters are put in.

With the catheters in place, the study may include the following tests.

* Filling cystometry - This test measures bladder capacity, bladder contractions and urinary leakage. Your bladder is slowly filled with sterile water. You will be asked to report any sensation you feel. You may be asked to cough, stand or bear down during the test.
* Voiding uroflometry - This test measures the strength of your urinary flow. You will be asked to urinate into a container linked to a computer that records your urine flow. The amount of urine left in your bladder after voiding is also measured.
* Urethral pressure study - This test measures the pressure and flow of urine out of your bladder. You will be asked to urinate while a sensor in the urethra measures the urethral pressure.
* Video cystourethrography - This test helps to identify structural problems in the bladder or urethra. The bladder is filled with contrast fluid (special dye that shows up in X-rays) and X-rays are taken as the fluid is voided.
* Electromyogram - This test helps measure muscle contractions that control urination. Electrode patches may be placed near the rectum or urethra to make the recording. You may be asked to try to tighten or relax your sphincter muscles.

What to expect afterwards

You will be able to go home when you feel ready. You can drive if you wish.
Results

Your results may be discussed with you immediately after the test or at a later date. Alternatively, a report may be sent to the doctor who recommended your test.
Recovering from urodynamic study

Drink plenty of clear fluids over 48 hours to help flush your bladder and reduce your risk of urinary infection.

Contact your GP if you develop any of the following symptoms, as you may have developed an infection:

* severe pain or pain that lasts for more than 48 hours
* high temperature
* burning sensation on passing urine or if your urine starts to smell
* heavy blood-stained urine

What are the risks?

Urodynamic study is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.

If the test involves X-rays, you will be exposed to some X-ray radiation. The level of exposure is about the same as the background radiation that you would receive naturally from the environment over 12 to 14 months. X-rays can harm a developing baby. If you are, or think you may be pregnant, tell your doctor before your appointment.
Side-effects

These are the unwanted but mostly temporary effects of a successful procedure.

Side-effects of urodynamic study include:

* feeling some discomfort when passing urine
* feeling mild stinging when passing urine
* some blood in the urine for 24 hours

Complications

This is when problems occur during or after the procedure. Most people are not affected. Complications of urodynamic study are uncommon but can include:

* urinary tract or bladder infection (cystitis) - you may need antibiotics to treat this
* damage to the urethra - this may require treatment with medicines or surgery
* allergic reaction to contrast dye - medicines are available to treat this

The exact risks are specific to you and differ for every person, so we have not included statistics here. Ask your doctor to explain how these risks apply to you.