Urodynamic Testing

If you have a problem with urine leakage or blocked urine flow, your doctor or nurse can help. One of the first steps may be urodynamic testing to find precisely what the problem is.

Urinary tract

Several muscles, organs, and nerves are involved in collecting, storing, and releasing urine. The kidneys form urine by filtering wastes and extra water from the bloodstream. The ureters are tubes that carry urine from the kidneys to the bladder. Normal urine flow is one way. If urine backs up toward the kidneys, infections are more likely.

The bladder, a hollow muscular organ shaped like a balloon, sits in the pelvis and is held in place by ligaments attached to other organs and to the pelvic bones. The bladder stores urine until you are ready to empty it. It swells into a round shape when it is full and gets smaller as it empties. A healthy bladder can hold up to 16 ounces (2 cups) of urine comfortably for 2 to 5 hours.

The bladder opens into the urethra, the tube that allows urine to pass outside the body. Circular muscles called sphincters close tightly to keep urine from leaking. The involuntary leakage of urine is called incontinence.

Nerves in the bladder tell you when it is time to empty your bladder. When the bladder begins to fill with urine, you may notice a feeling that you need to urinate. The sensation becomes stronger as the bladder continues to fill and reaches its limit. At that point, nerves in the bladder send a message to the brain, and your urge to urinate intensifies.

When you are ready to urinate, the brain signals the sphincter muscles to relax. At the same time, the brain signals the bladder muscles to tighten, squeezing urine out. Urine can then leave the bladder through the urethra. When these signals occur in the correct order, normal urination occurs.

Problems in the urinary system can be caused by aging, illness, or injury. The muscles in your ureters, bladder, and urethra tend to become weaker with age. You may have more urinary infections because your bladder muscles have weakened and cannot empty your bladder completely. Also, weakening in the muscles of the sphincters and the pelvis can cause incontinence because the sphincter cannot remain tight enough to hold urine in the bladder or does not have enough support from the pelvic muscles.

Urodynamics is the study of how the body stores and releases urine. Urodynamic tests help your doctor or nurse see how well your bladder and sphincter muscles work and can help explain symptoms such as

• incontinence
• frequent urination
• sudden, strong urges to urinate
• problems starting a urine stream
• painful urination
• problems emptying your bladder completely
• recurrent urinary tract infections

These tests may involve imaging equipment that films urination or may be as simple as urinating behind a curtain while a doctor or nurse listens.

source: http://kidney.niddk.nih.gov/kudiseases/pubs/urodynamic/index.htm