Urinary Retention: Diagnosis
How is urinary retention diagnosed?
Your doctor will order a number of tests to diagnose your condition.
History of Complaints and Physical Examination
A physician will suspect urinary retention by your symptoms and will attempt to confirm the diagnosis with a physical examination of the lower abdomen. The physician may be able to feel the distended bladder by lightly tapping on your lower belly. Tapping or striking for diagnostic purposes is called percussing.
Urine Sample
A urine sample will be examined for signs of infection, which may be a cause or a result of urinary retention.
Bladder Scan
A bladder scan uses a portable ultrasound device that can determine how much urine is in your bladder. You will be asked to urinate, and then your doctor or nurse will use the bladder scan to determine the post-void residual (PVR). The word residual refers to the amount of urine left in the bladder after urination. If you typically have a PVR of 100 milliliters or more, you are considered to have chronic urinary retention.
Cystoscopy
Your doctor may use a cystoscope to see inside your bladder and urethra. The cystoscope has lenses like a telescope or microscope. These lenses let the doctor focus on the inner surfaces of the urinary tract.
Some cystoscopes use optical fibers made of flexible glass that carry an image from the tip of the instrument to a viewing piece at the other end. The fiber-optic cystoscope is as thin as a pencil and has a light at the tip. The doctor can use the cystoscope to find and perhaps remove a stone that may be blocking the bladder opening. The device can help the doctor identify narrowing of the urethra from prostate enlargement or UTI.
X Ray and Computerized Tomography (CT) Scan
A conventional x ray may show a spot where the urinary tract is narrowed or obstructed. It may show that the bladder is out of its normal position. CT scans use multiple x-ray images to construct a better view of internal organs, which may help find stones or other obstructions.
Blood Test for Prostate-specific Antigen (PSA)
Men may be given a blood test to measure their PSA, a substance in the blood that may indicate prostate cancer or other prostate problems. A high PSA score may prompt further tests, such as a transrectal ultrasound, with or without biopsy of the prostate.
Prostate Fluid Sample
The doctor may ask for a prostate fluid sample to check for prostatitis—inflammation of the prostate—a condition that can cause the prostate to swell and pinch the urethra. The doctor will obtain the sample by inserting a gloved finger into the rectum and massaging the prostate until fluid drains through the urethra. A doctor will not massage a prostate for prostatic fluid if urinary retention is suspected as the primary diagnosis. Only when urinary retention is ruled out would the doctor do this test.
Urodynamic Tests
Urodynamic tests include different techniques to measure the bladder’s ability to empty steadily and completely. In a pressure flow study, you will be asked to empty your bladder so that a special catheter can measure the pressure required to start a stream. This pressure flow study helps to identify bladder outlet obstruction from prostate enlargement or cystocele.
If your doctor or nurse thinks your urinary problem is related to nerve damage, you may be given an electromyography. This test measures the muscle activity in the urethral sphincter using sensors placed on the skin near the urethra and rectum. Sometimes the sensors are on the urethral or rectal catheter. A catheter is a thin, flexible tube that can be guided into openings of the body. Muscle activity is recorded on a machine. The patterns of the impulses will show whether the messages sent to the bladder and urethra are coordinated correctly.
Information Source: National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) (October 2007). Urinary Retention (NIH Publication No. 08–6089). Retrieved February 5, 2008 from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, U.S. Department of Health and Human Services. Web site: http://kidney.niddk.nih.gov/kudiseases/pubs/UrinaryRetention/index.htm
