Lower urinary tract symptoms do not help to detect bladder outlet obstruction in men

D`Silva KA, Dahm P, Wong CL. Does this man with lower urinary tract symptoms have bladder outlet obstruction?: The Rational Clinical Examination: a systematic review. JAMA. 2014;312:535-42.

Review questions

In men with lower urinary tract symptoms, do questionnaires about symptoms help to detect bladder outlet obstruction (a blockage that slows or stops urine flow out of the bladder)? Can a bladder ultrasound (scan) accurately measure urine volume in the bladder so that a catheter-based procedure can be avoided?

Background

Often, men will visit their family doctor about lower urinary tract symptoms, such as a weak or intermittent urine stream, a feeling of incomplete urination, frequent urination, hesitancy, straining, prolonged urination, dribbling, urgency, urge incontinence, or getting up often in the night to urinate. These symptoms can have several different causes, including medications, urinary tract infections, and problems with the structure or function of the lower urinary tract. Bladder outlet obstruction is a blockage that slows or stops urine flow out of the bladder. It can lead to complications such as recurring urinary tract infections, bladder stones, or kidney damage.

Usually bladder outlet obstruction is diagnosed with tests that require a catheter (a small tube) to be inserted via the penis into the bladder. It would be helpful if family physicians could determine if a man had a bladder outlet obstruction based on symptoms. A bladder ultrasound (scan) can also measure the amount of urine in the bladder without the need for a catheter.

How the review was done

The researchers did a systematic review, searching for studies that were published up to March 2014.

They found 9 studies with 1262 men (average age 62 to 68 years), which assessed whether the presence of  lower urinary tract symptoms could help to detect bladder outlet obstruction. They also found 20 studies that compared urine volumes measured by bladder scans with bladder catheter methods.

What the researchers found

Detecting bladder outlet obstruction

5 studies had quality ratings of 3 out of 5; the other 4 studies were of poorer quality.

Of the 5 studies with the highest quality, 4 used the International Prostate Symptom Score, which collects information on the following symptoms:  sensation of incomplete emptying, urinary frequency, intermittent stream, urge incontinence, weak urine stream, straining, and night-time urination. The other study used the individual symptoms of intermittent stream and dribbling.

In men with urinary tract symptoms, 64% had bladder outlet obstruction.

Using symptoms did not help to detect bladder outlet obstruction.

Urine volume

Bladder scans measured urine volume accurately compared with bladder catheter methods.

Conclusions

In men with lower urinary tract symptoms, using symptom questionnaires or individual symptoms does not help to detect bladder outlet obstruction. A bladder scan can be used to measure urine volume instead of using a bladder catheter.