'Plumbing' problems? Ultrasound an easier way to detect bladder obstructions

The Bottom Line

  • Lower urinary tract symptoms (problems urinating) are common in men as they age and are often caused by an enlarged prostate, but can be due to other issues such as bladder stones or cancer.
  • The standard test for bladder outlet obstruction involves insertion of a catheter and is invasive and uncomfortable.
  • Research evidence shows that – while questionnaires about symptoms do not accurately detect bladder outlet obstructions – bladder scans (ultrasound) are as effective as the more painful catheter procedure for diagnosis.

Lower urinary tract symptoms are common, especially in older men (1). These annoying and sometimes painful symptoms include difficulty urinating, urinating too frequently, and having to get up many times at night to urinate (2). Symptoms are often caused by a bladder outlet obstruction – a blockage that slows or stops the flow of urine from the bladder (3).

One of the most common causes of an obstruction is an enlarged prostate (a condition called benign prostatic hyperplasia) which can often be treated effectively with medication. Click here for information about drug treatments. However, there are other reasons why men may have lower urinary tract symptoms (including an infection, side effects of medications or chronic health issues such as Parkinson’s) and other serious causes of an obstruction (including bladder stones or cancer). Left untreated an obstruction can result in serious problems such as recurring urinary tract infections and even kidney damage (3).

Since the causes vary and the consequences can be serious, it’s important to get an accurate diagnosis and identify the best treatment – but that’s when things become uncomfortable. The traditional test is rather invasive: a urologist inserts a small tube (catheter) into the bladder through the penis, and the bladder is filled with a saline solution to measure volume and pressure.

Hoping for a simpler way, researchers conducted studies to see whether obstructions could be accurately detected by asking patients to answer a series of questions about their symptoms. A recent systematic review included 10 such studies, involving more than 1,200 older adult men (4). The participants completed a commonly used questionnaire called the International Prostate Symptom Score that collects information on specific lower urinary tract symptoms (5).


The review also included 20 studies involving almost 1400 men in which bladder scans were used to measure urine volume (4). The scans were done with an ultrasound, which is non-invasive and not painful.  For both sets of studies, the accuracy of the diagnoses using the “kinder, gentler” methods was assessed and compared with the traditional procedure.

What the research tells us

So will completing a questionnaire be enough to tell whether you have a bladder outlet obstruction? Regrettably, no. But on the bright side, bladder scans appear to be a viable alternative to bladder catheters as there was strong evidence that they measure urine volume with the same accuracy. That’s good news for patients and their doctors as it means an easier, more comfortable procedure may be used for diagnosing bladder outlet obstructions and determining the appropriate treatments.

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  1. Irwin DE, Kopp ZS, Agatep B, Milsom I, Abrams P. Worldwide prevalence estimates of lower urinary tract symptoms, overactive bladder, urinary incontinence and bladder outlet obstruction. BJU Int. 2011 Oct;108(7):1132-1138.
  2. Tanguay S, Awde M, Brock G et al. Diagnosis and management of benign prostatic hyperplasia in primary care. Can Urol Assoc J. 2009; 3 (3)(suppl 2):S92-S100.
  3. Abrams P, Chapple C, Khoury S, Roehrborn C, de la Rosette J, International Consultation on New Developments in Prostate Cancer and Prostate Diseases. Evaluation and treatment of lower urinary tract symptoms in older men. J Urol. 2013 Jan; 189(1 Suppl):S93-S101.
  4. 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 Aug;312(5):535-42.
  5. McVary K, Roehrborn C, Avins A et al. Update on AUA guideline on the management of benign prostatic hyperplasia. J Urol. 2011; 185(5):1793-1805.

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