Board Review

A 60-year-old man is evaluated for urinary frequency of several years' duration. His symptoms have worsened over the past 6 to 12 months, and he notes several episodes of nocturia over the past 3 months. He reports no fever or dysuria. Medical history is notable for hypertension, and his only medication is amlodipine; he takes no over-the-counter medications.

On physical examination, blood pressure is 140/60 mm Hg, and pulse rate is 64/min. BMI is 30. There is no evidence of suprapubic bladder distention. The prostate is diffusely enlarged, firm, and nontender without nodules. The penis appears normal. The remainder of the examination is normal.

Which of the following is the most appropriate next step in management?

A) Postvoid residual urine volume

B) Prostate ultrasonography

C) Urinalysis

D) Urine flow studies

Answer: C - Urinalysis

Objective: Evaluate a patient with benign prostatic hyperplasia.

Key Point

In patients with usual symptoms of benign prostatic hyperplasia (BPH), a careful history and physical examination can usually render the diagnosis; a urinalysis is also indicated in evaluating BPH to exclude infection, malignancy, or postobstructive nephropathy.

Obtaining a urinalysis is the most appropriate next step in the management of this patient with benign prostatic hyperplasia (BPH), a common cause of lower urinary tract symptoms (LUTS). Most men age 60 years and older have LUTS of varying degree associated with prostate enlargement. Symptoms may be mild and include decreased urinary stream, incomplete bladder emptying, urinary frequency, and nocturia. Severe symptoms may include urinary retention, urgency, and incontinence. Diagnosis of BPH in most cases is by history and physical examination, with exclusion of other potential causes of LUTS, which may include malignancy (prostate, bladder), infection (prostatitis, sexually transmitted infections), neurologic causes (spinal cord injury, stroke, Parkinson disease), medical conditions (poorly controlled diabetes mellitus, hypercalcemia), and behavior (alcohol or caffeine intake, excessive water consumption). When these other causes are not highly suspected, only a urinalysis is recommended to exclude infection (bacteria and pyuria), malignancy (hematuria), or postobstructive nephropathy (active urine sediment). Prostate-specific antigen testing is not routinely indicated for diagnosis or following the course of BPH because it may be inconsistently elevated due to prostate hypertrophy, and increased levels of prostate-specific antigen associated with BPH do not reliably correlate with LUTS.

An increased postvoid residual urine volume, determined by catheterization or ultrasonography, is supportive of the presence of BPH but is not required for diagnosis. It has also been used as an indicator of significant obstruction to inform decisions regarding the need for surgical intervention in BPH, although there is not significant evidence that the postvoid residual volume is a reliable predictor of surgical outcomes. Because this patient has no evidence of significant urinary retention, measurement of postvoid residual volume is not indicated.

Prostate ultrasonography is an effective method for measuring prostate volume or evaluating other prostate abnormalities such as nodules. However, volume measurement by ultrasonography is not required for diagnosis of BPH, and this patient has no other indication for prostate imaging.

Urine flow studies are an accurate means of determining bladder outlet obstruction. However, this study is usually reserved for patients with atypical symptoms in whom the diagnosis of BPH is unclear or if there is concern for other urinary tract flow problems in addition to BPH. Because this patient has mild, typical symptoms consistent with BPH, urine flow studies are not indicated.

Beckman TJ, Mynderse LA. Evaluation and medical management of benign prostatic hyperplasia. Mayo Clin Proc. 2005 Oct;80(10):1356-62. Link Out