Urodynamic studies (UDS) are a series of continued tests which examine the bladder, sphincters, and urethra to test how well the body holds and releases urine. These tests reveal how well a bladder is working and can identify causes of leaks or blockages. Many different types of urodynamic tests are available, but it is not uncommon to see all of the following tests performed at the same time:
- Cystometry – used to measure how much urine the bladder can hold and pressure inside the bladder
- Electromyography – tests nerves in the pelvic floor and electrical activity of pelvic muscles
- Voiding Pressure Study – measures bladder pressure during urination and flow rate of urine
- Urethral Pressure Profile – a workup of the strength of the urethra and its outlet
- Uroflowmetry – measures the amount and speed of urine during urination
As noted, these tests are ran on the bladder, sphincters, and urethra. Together, these make up the lower urinary tract. The bladder stores urine and is held in place by pelvic floor muscles. When not full of urine, the bladder relaxes. Nerve signals alert the brain when the bladder started to get full, and when full tell the brain it is time to urinate. The bladder muscles then contract and urine is forced out of the body through the urethra. The sphincters are in the urethra and keep the urethra closed to prevent leakage of urine. The sphincters open when the brain signals it is time to urinate. This is how a healthy lower urinary tract works; UDS are ran when the lower urinary tract is not working normally.
UDS can be useful in finding the root causes of problems such as
- Bladder not fully emptying
- Frequent urination
- Weak flow of urine
- Intermittent urination
- Frequent urinary tract infections
Some of these symptoms are signs of an overactive bladder (OAB), so UDS may be useful for diagnosing OAB when physical exams and simple urine tests do not reveal the cause.
There are not typically any severe side effects of UDS. Drinking multiple glasses of water before the test and placed a warm, moist washcloth over the urethral opening afterwards may help with the slight discomfort that may occur.