Cystometry

What is cystometry?

Cystometry is a test used to look for problems with the filling and emptying of the bladder. It helps to diagnose urine control problems. The bladder is part of the urinary tract. It’s a hollow muscular organ that relaxes and expands to store urine.

Cystometry measures the amount of urine in the bladder. That figure is compared with the bladder pressure and how full you think your bladder is. The result tells your healthcare provider about muscle function, mechanics, and nerve response of the bladder and urinary tract.

Normally, the bladder sends messages to the brain through nerve pathways when it needs emptying. The spinal cord then sends a message to the bladder to contract and start the reflex of urinating. Normally, you can override this reflex voluntarily to hold and control urine.

Some conditions may interfere with the muscular function or nerve pathways between the bladder and the brain. These conditions may lead to loss of bladder control or urinary blockage. Cystometry may be used to find the cause of such problems.

Why might I need cystometry?

Cystometry may be recommended to check for problems of the bladder and urethra. Conditions that may cause problems of the bladder and urethra may include:

Neurogenic bladder dysfunction. The bladder doesn't work correctly due to a problem in the nervous system, such as a spinal cord tumor, Parkinson disease, or a spinal cord injury.
Multiple sclerosis. An unpredictable disease of the central nervous system that changes communication between the brain and other parts of the body.
Diabetes. A health problem that happens when the body is not able to use sugar for growth and energy for daily activities. It can lead to nerve damage.
Prostate enlargement. Prolonged, untreated prostate enlargement can cause problems emptying the bladder.

Problems in the urinary system can also be caused by aging, other illness, or injury.

Weak bladder muscles may result in not being able to empty your bladder completely. This is called urinary retention. Weak muscles of the urinary tract and pelvis can lead to loss of urine control. This is because the muscles can't stay tight enough to hold urine in the bladder. Or the bladder does not have enough support from the pelvic muscles to stay in its correct position. Cystometry may be used to find the cause of symptoms like these.

There may be other reasons for your healthcare provider to advise cystometry.

What are the risks of cystometry?

Some complications of cystometry may include:

Urinary tract infection (UTI)
Autonomic reflex (severe headache, increased blood pressure, lower heart rate, sweating, and flushing) in people who have a spinal cord injury or a spinal cord tumor

Cystometry should not be done in someone with a UTI.

There may be other risks depending on your specific health condition. Be sure to discuss any concerns with your healthcare provider before the test.

Straining with urination and certain medicines may affect the results of a cystometry test.

How do I get ready for cystometry?

Your healthcare provider will explain the test and you can ask questions.
You may be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if anything is not clear.
Generally, not eating (fasting) or limiting fluids is not needed.
Tell your provider if you are pregnant or think you may be pregnant.
Tell your provider if you are sensitive to or are allergic to any medicine, latex, tape, and anesthesia.
Make sure your healthcare provider has a list of all medicines (prescribed and over-the-counter), herbs, vitamins, and supplements that you are taking.
Tell your provider if you have a history of bleeding disorders or if you are taking any blood-thinning (anticoagulant) medicines, aspirin, or other medicines that affect blood clotting. You may need to stop these medicines before the test.
Tell your provider if you think you may have a UTI. Symptoms include frequent urination, pain or burning when passing urine, fever, and urine that looks dark, cloudy, or reddish in color and smells bad.
You may need to start an antibiotic a day or so before the test. This is to help prevent a urinary tract infection.
People who have problems with constipation may need to use an enema before the test.

Based on your health condition, your healthcare provider may ask for other specific preparation.

What happens during cystometry?

Cystometry may be done on an outpatient basis. This means you go home the same day. Or it may be done during a hospital stay. Procedures may vary depending on your condition and your healthcare provider's practices.

Generally, cystometry follows this process:

You will need to remove your clothing, jewelry, or other objects that may interfere with the test.
If you are asked to remove your clothing, you will be given a gown to wear.
You will be asked to empty your bladder as well as you can before starting.
You will be placed on your back on an exam table.
A soft, flexible tube (catheter) will be put in through the urethra until it reaches the bladder. You may have some mild pain when this is done.
The amount of urine left in your bladder will be measured. (This is called residual urine.)
Another catheter or pressure probe may be put into the rectum or vagina to measure pressure in the belly. Or electrodes may be stuck to your skin on either side of the anal opening to measure muscle function.
A small amount of room temperature fluid will be put through the catheter into the bladder. Next, an equal amount of warmed fluid will be put in. You will be asked to describe what you feel when this is done, such as warmth, the need to urinate, discomfort or pain, or nausea.
The fluid will be drained out through the catheter.
The catheter will be connected to a measuring device called a cystometer (a tool that measures bladder pressure).
Fluid or gas will be slowly put through the catheter into the bladder. You will be asked to tell when you first feel the urge to urinate and when you feel like you must urinate. Bladder pressure will be recorded during this time.
When the bladder is completely full, you will be asked to empty your bladder while pressure is being recorded. A portable commode chair will be available for you and the catheters will stay in place.
In some cases, medicine that can affect the bladder’s muscle tone may be given, and the test will be repeated in 20 to 30 minutes.
When all tests have been done, the catheter will be removed. The rectal probe or sticky electrodes will also be removed.
You may have discomfort during this test, such as flushing, sweating, nausea, pain, bladder filling, and urgent need to urinate. Tell the healthcare provider how you are feeling.

What happens after cystometry?

There is no special type of care needed after cystometry. You may go back to your normal diet and activities unless your healthcare provider tells you otherwise.

You will be urged to drink extra fluids to dilute your urine and reduce urinary discomfort, such as burning.

You may feel some urinary discomfort, but it should become less over time. Warm sitz baths or tub baths may help.

You may see blood in your urine after the test. The amount of blood will lessen over time.

Your healthcare provider may have you take an antibiotic to prevent a urinary tract infection.

Call your healthcare provider to report any of the following:

Fever
Chills
Belly pain
Continued or increased blood in your urine
Less urine output than normal

Your healthcare provider may give you other instructions after the test, depending on your situation.

Next steps

Before you agree to the test or procedure, make sure you know:

The name of the test or procedure
The reason you are having the test or procedure
What results to expect and what they mean
The risks and benefits of the test or procedure
What the possible side effects or complications are
When and where you are to have the test or procedure
Who will do the test or procedure and what that person’s qualifications are
What would happen if you did not have the test or procedure
Any alternative tests or procedures to think about
When and how you will get the results
Who to call after the test or procedure if you have questions or problems
How much you will have to pay for the test or procedure