Most Appropriate Initial Study
Urinalysis with culture is the most appropriate initial study for this patient with chronic scrotal pain, urinary symptoms, and a boggy, tender prostate on digital rectal examination. 1
Clinical Reasoning
This elderly man presents with a classic constellation of symptoms suggesting chronic bacterial prostatitis/chronic pelvic pain syndrome:
- Six months of chronic pelvic/scrotal pain (both dull and sharp)
- Lower urinary tract symptoms (incomplete emptying, urgency, frequency)
- Sexual dysfunction (erectile difficulties, painful premature ejaculation)
- Boggy, tender prostate on digital rectal examination
- History of prior sexually transmitted infection 2, 1
The American Urological Association emphasizes that urinalysis with microscopy is essential to identify pyuria, hematuria, or bacteriuria in patients presenting with dysuria and testicular pain. 1 This basic laboratory assessment should document symptoms and exclude other disorders in the differential diagnosis. 2
Why Urinalysis with Culture is the Correct Initial Test
Urinalysis with culture serves multiple critical diagnostic functions:
- Identifies infection: Detects pyuria, bacteriuria, and specific causative organisms in chronic bacterial prostatitis 1
- Guides antibiotic therapy: Culture and sensitivity results direct appropriate antimicrobial treatment 3, 4
- Rules out other pathology: Excludes hematuria that would require further workup for malignancy 2
- High negative predictive value: Negative urinalysis effectively rules out urinary tract infection with near 100% accuracy 5
The American Urological Association specifically states that urine culture may be indicated even in patients with negative urinalysis to detect lower levels of bacteria that are clinically significant but not readily identifiable with dipstick or microscopic exam. 2
Why Other Options Are Not Initial Studies
Post-void residual volume measurement is useful for assessing bladder emptying and potential outlet obstruction, but it does not establish the underlying diagnosis. 2 While the American Urological Association recommends evaluating for incomplete bladder emptying in all patients with suspected interstitial cystitis/bladder pain syndrome, this is part of the physical examination rather than the primary diagnostic study. 2
MRI of the prostate is not indicated as an initial study. There is no role for advanced imaging before establishing whether infection is present. 1
Ultrasonography of the testicles would be appropriate for acute scrotal pain to rule out testicular torsion or epididymitis, but this patient has chronic symptoms (six months) and a normal genital examination. 2 The ACR Appropriateness Criteria emphasize that ultrasound is primarily for acute presentations, particularly when torsion is suspected. 2
Urine nucleic acid amplification test (NAAT) for sexually transmitted infections could be considered, but only after basic urinalysis establishes the presence or absence of infection. 1 Given his monogamous relationship with his wife and remote STI history, this is not the initial priority.
Clinical Significance of Chronic Prostatitis and Sexual Dysfunction
The link between chronic bacterial prostatitis and premature ejaculation is well-established:
- Chronic bacterial prostatitis is found in 52-64% of men with premature ejaculation 4
- Chlamydia trachomatis infection in chronic prostatitis is independently associated with premature ejaculation (adjusted OR 3.21) 6
- Successful eradication of causative organisms leads to marked improvement in ejaculatory latency time and control in 83.9% of patients 3
This underscores why identifying and treating the underlying infection is paramount—it directly addresses both the pain symptoms and the sexual dysfunction. 6, 3, 7
Common Pitfalls to Avoid
Do not skip basic urinalysis in favor of advanced imaging. The American Urological Association guidelines consistently emphasize that basic laboratory testing including urinalysis and urine culture forms the foundation of diagnosis. 2, 1
Do not assume normal urinalysis excludes chronic bacterial prostatitis. Lower bacterial counts may not be detected on routine urinalysis, necessitating formal culture. 2
Do not confuse this chronic presentation with acute scrotal pain requiring urgent ultrasound. The six-month duration and normal testicular examination make acute pathology like torsion extremely unlikely. 2