Urodynamics: What, When, Why
The American Urological Association (AUA)
(IC) treatment guidelines
state that urodynamics should
be considered as an aid to diagnosis only for complex cases of IC. These tests are not
necessary for making the
diagnosis in uncomplicated cases.
There are no agreed-upon urodynamic
diagnostic criteria for IC, inconsistent findings in IC patients—and, these
tests can be very painful and uncomfortable for IC patients.
However, some cases of IC are complicated and may require urodynamic testing. For example, your doctor
may do additional testing if there are signs and symptoms of other
problems, such as incontinence, overactive bladder, blood or pus in
the urine, endometriosis, or gastrointestinal conditions. For men, a
misdiagnosis of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) can
also make it more challenging to diagnose IC.
Urodynamics isn’t one test but a group of
tests to determine how your lower urinary tract is functioning. It gives
physicians information on how much your bladder can hold, how much it can hold
before you feel the need to urinate, how the bladder muscle is functioning,
whether there might be any sphincter or pelvic floor dysfunction that hinders
the outflow of urine, and whether you are retaining any urine in your bladder
after it feels like you’re through urinating.
Testing & IC
tests can be very difficult for IC patients. The testing requires that the
doctor insert a small catheter into the bladder; after the patient empties
their bladder, the doctor, nurse, or technician may refill it to take special
measurements. It usually takes about 30 minutes for the doctor to perform the
Because when you should undergo urodynamic
tests if you have IC isn’t 100 percent clear, ask your doctor these questions
to help you weigh the decision:
- What question about my disease will the tests answer?
- What changes in my treatment would we make based on the
- How can urodynamics be made as comfortable as possible
- How much does the testing cost?
Blaivas, MD, believes that patients with IC who don’t respond to treatment
should undergo videourodynamics. That’s because, when patients don’t get
better, it’s important to look for other conditions that could be causing their
symptoms, including overactivity of the bladder muscle, obstruction of or
outpouching (diverticulum) in the urethra, or even bladder cancer. Urodynamics
help diagnose bladder muscle overactivity, urethral obstruction, and urethral
diverticula. Dr. Blaivas also finds that urodynamic tests offer additional
useful information such as the relationship among bladder filling, bladder
volume and the intensity of urge or pain and whether there is bladder muscle
overactivity or the bladder is unable to expand. Urethral diverticulum or
obstruction and overactive bladder (OAB) require different treatment from those
prescribed for IC—without urodynamics, Dr. Blaivas says, the doctor wouldn’t
know whether you had them.
Christopher Payne, MD, notes that no studies support use
of invasive modes of urodynamics to help evaluate patients who may have IC. A
study of nearly 400 women with IC-like symptoms showed that the older, strict
diagnostic criteria that included urodynamics and cystoscopy with
hydrodistention resulted in misdiagnosis in up to 60 percent of patients. After
that study came out, Dr. Payne shifted his approach and now very selectively
uses urodynamics. He believes that urologists can judge whether the bladder has
lost its ability to expand clinically, without urodynamics and finds that bladder
diaries are more useful and relevant than urodynamics for evaluating bladder
capacity. However, because in his practice, men with IC have bladder neck
obstruction more often than women, Dr. Payne may use routine uroflow and
postvoid residual studies for better understanding the presentation of pelvic
symptoms in some male patients.
Types of Urodynamic Tests
many types of urodynamic tests which help evaluate how well your bladder fills
and empties, the rate of your stream, and any abnormalities in bladder muscle
contractions and leakage. An example of a noninvasive urodynamic test is
listening to a patient void. For this test, the doctor or nurse asks you to
urinate behind a curtain. While listening to your stream, the provider records
observations about rate of flow. However, urodynamic testing usually involves
more sophisticated medical procedures:
To help describe
urodynamics, the ICA spoke with urogynecology nurse Tamara Dickinson, RN, of UT
Southwestern Medical Center in Dallas, who performs these tests for the
practice there. Tamara, in fact, started her urology career doing urodynamics,
lectures to other nurses about it, and wrote the Society for Urologic Nurses
and Associates’ patient fact sheet on the testing.
Uroflow Test or Uroflowmetry
test measures how quickly you empty your bladder (urine speed and volume).
Pressure uroflowmetry can help your doctor assess difficulty voiding,
indicating weak bladder muscles or an obstruction. Weak bladder muscles and
obstructed urine streams produce abnormal results.
Tamara shared that patients undergoing
urodynamics may be given an antibiotic beforehand or after the procedures to
avoid infection and need to arrive for testing with a full bladder. Then, they
urinate using a special commode chair that has a funnel underneath with a
transducer, that not only measures how much urine was in your bladder but also
the force of the stream of urine. This part of urodynamics is called the
Post Void Residual Volume
For this part of the testing a catheter will
be inserted into your bladder to drain out any remaining urine, showing whether
you can empty your bladder completely. The doctor or nurse or technician will ask
you to completely empty your bladder. It is normal when the bladder feels empty
for a small amount of urine to remain in the bladder.
post void residual volume test measures how much urine remains (usually one or
two ounces). High volumes of urine may indicate urinary tract infection,
incontinence, or other conditions. The doctor may also request that a lab check
the urine sample for signs of infection.
doctors use an ultrasound to measure post void residual through sound waves;
abnormal results are post void residuals of more than 200 mL.
Cystometry (Cystometrogram or Filling
The next part of the test is called a
“cystometrogram” or “filling cystometry,” which measures the pressure in your
bladder. To do this, after your bladder is empty, the nurse or technician must
also insert another catheter with a small, suppository-like balloon on the end,
which is a pressure sensor, into the vagina or rectum.
Inserting the catheters may be uncomfortable
for some IC patients, although Tamara noted she isn’t familiar with IC
patients’ experience because the physicians in her practice don’t routinely
have IC or painful bladder syndrome (PBS) patients undergo these tests.
Nevertheless, she said, how the nurse goes about inserting the catheters can
make a difference in the patient’s comfort. Lubricant is used with both
insertions, and Tamara also inserts the catheters very gently, having patients
use relaxation techniques, such as deep breathing, as she advances the
catheter. The catheters, she noted, are 7 French—about the size of a spaghetti
noodle—and much smaller than the catheters usually used for bladder
provider then fills your bladder with warm water and measures the levels of
pressure in the bladder, rectum, urethra, and surrounding area. Because the
bladders of IC patients typically hold less urine, the filling cystometry
measurements are usually below the normal ranges. By asking patients to cough
during this procedure, doctors can also check for stress incontinence.
doctor or nurse may then ask you to empty your bladder and test the pressure
levels in your bladder as you urinate and your urine’s rate of flow. In men,
this test helps diagnosis bladder obstruction caused by an enlarged prostate.
During the cystometry, you
may have some small electrodes placed on either side of the rectum that help
record the electrical activity of muscles. By evaluating the patterns of impulses,
your doctor can learn more about potential problems with nerve signaling
between your bladder and urethra.
That is especially useful for detecting
dysfunctional voiding patterns, (such as not relaxing the pelvic floor muscles
to urinate), which could lead to unstable bladder contractions, resulting in
frequency and urgency. Today, the electrodes are on small bandage-like adhesive
patches. Needles or wires that go into tissue have greater potential to cause
discomfort, but they are rarely used today, said Tamara. “A few people still
use needle electrodes, but typically those are neurourologists working with
patients who have impaired sensation, such as spinal cord injured patients,”
Special x-rays can also help your
doctor better understand any abnormalities with the size and shape of your
bladder and urinary tract.
nurse or technician fills the bladder with sterile water, saline solution, or,
sometimes, a contrast solution (a kind of dye solution that shows up on x-ray). When the contrast solution is used, the tests are referred
to as “videourodynamics,” because the operator can watch the process on a
monitor. That isn’t used in her urogynecology practice, said Tamara, who
explained that videourodynamics are more commonly used for more complex
patients, such as neurologically
impaired patients (for example, patients with spinal cord injury or multiple
sclerosis) or patients with a complicated history of incontinence.
As the bladder fills, the operator will
record different pressure measurements, will find out how much the bladder
holds, and will ask you to cough and push or bear down to check for leakage.
She or he will also ask when you first feel your bladder filling, how it feels
during filling, and when you feel like you need to void.
The filling process can be uncomfortable for
IC patients. At this stage, said Tamara, “If I have a patient who’s got painful
bladder symptoms, I’m not going to fill them as fast as I normally fill other
patients. Filling more slowly helps avoid discomfort.” On the other hand, many
urodynamic centers will want to fill your bladder at a standard rate so that
the test results can be interpreted accurately when they are compared with
results from patients without IC.
Sometimes, a further test is done, called a
“urethral pressure profile,” which requires moving the catheter in and out.
But, said Tamara, “That’s something that you’re more interested in if you’re
looking at incontinence or prolapse. I wouldn’t usually do a urethral pressure
profile if I had a patient who had a lot of pain and suspected IC.”
The next test is called a “voiding pressure
study” or “pressure flow study.” Once you feel that your bladder is full,
you’ll be asked to urinate again using the special commode chair. The catheters
are left in place for this. This test allows the operator to see how the
bladder functions as it empties and whether anything is hindering the outflow
Tips for IC
Patients Having Urodynamic Tests
for a few hours after urodynamic tests, especially when you urinate, is normal
even for people who do not have IC. To
help keep your IC symptoms in check, plan ahead.
Before Urodynamic Testing
- Ask the
doctor about any changes in your treatment plan. Find out if you will be able
to get a rescue solution or a stronger pain medicine to help manage the side
effects of the procedures. Get the prescription filled before the procedure.
- Review your
personal IC flare strategies.
- Ask your
healthcare provider for any special instructions. Some urodynamic tests,
require you to arrive with a full bladder and others an empty one.
- Find a family
member or friend who can drive you and bring you home.
- Let your healthcare
team know how you are feeling that day. When you arrive, let the nurse and
doctor know if you are having IC pain or any other discomfort.
- Bring your
pain and voiding diaries with you. Discuss your symptoms and ask about special
precautions to reduce pain and discomfort associated with the procedure such as
using a very small catheter.
After Urodynamic Testing
- Put your IC
flare remedies into action.
- Take pain
medicine, as needed, to control added discomfort and pelvic pain.
- Sip water,
aim for eight ounces each half-hour for two hours.
- Ask your
doctor if warm baths are okay. If not, try relieving discomfort by placing a
warm, damp washcloth over the urethral opening.
doctor’s orders regarding any changes to your IC treatment plan.
- Call the
doctor’s office if you experience higher levels of pain, chills or fever.
Posted March 25, 2011