Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (252 page)

   Chronic bacterial prostatitis (WHO class II) is manifested (in a minority of patients) by symptoms of recurrent urinary tract infection (frequency, dysuria, urgency) with repeated isolation of the same organism from urine, perineal discomfort, and occasionally a low-grade fever. However, other patients may be asymptomatic, with persistent or recurrent bacteria in urine found incidentally during a workup for lower abdominal/ perineal/genital pain or bladder irritation/obstruction.

   Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is manifested by chronic pelvic pain for at least three of the preceding 6 months in the absence of other identifiable causes. Despite the name, it is uncertain that the symptoms can be traced to the prostate. WHO class IIIA CP/CPPS includes patients with inflammatory cells in expressed prostatic secretions, post–prostate massage urine, or seminal fluid. WHO class IIIB includes the balance of patients with chronic prostatitis or pelvic pain.

   Asymptomatic inflammatory prostatitis (WHO class IV) is usually diagnosed incidentally, during prostate biopsy or during a workup for infertility or cancer. The natural history of the syndrome is not well understood.

   Laboratory Findings

   Acute bacterial prostatitis (WHO class I)

   Blood: leukocytosis and an elevated serum prostate-specific antigen (PSA) support the diagnosis and should be followed by a digital rectal exam.

   Urine: A Gram stain and culture should be obtained in all suspected cases. Bacteria causing acute prostatitis are easily recoverable from urine (prostate massage is contraindicated in suspected acute prostatitis, because it may induce sepsis). Culture usually reveals the causative organism (unless antibiotics were used recently).

   Recovered organisms are generally those that induce UTI and urethritis:
Escherichia coli, Klebsiella, Proteus, Pseudomonas, Enterobacter, Enterococcus, Serratia, and Staphylococcus aureus
.

   WBCs are found in the centrifuged urine sediment of the last portion of the voided urine specimen.

   Chronic bacterial prostatitis (WHO class II)

   A presumptive diagnosis relies on chronic (>3 months) or recurrent urogenital symptoms, especially if bacteriuria is present. The standard diagnostic confirmation test is the Meares-Stamey four-glass test, which compares cultured bacterial colony counts in the first 5–10 mL (urethral) and midstream (bladder) urine specimens, a prostatic secretion (expressed by a 1-minute gentle prostate massage), and the first 5–10 mL of post–prostatic massage voided urine. If the bacteriuria baseline is <10
³
/mL, chronic bacterial prostatitis is suspected if the leukocyte count in the prostatic secretion is >12 per high-power field and confirmed if >20 per high-power field (unless leukocytes were also present in the bladder urine specimen). A simpler “two-glass” method compares cultured bacterial colony counts collected from the midstream urine specimen (followed by the prostate massage) with the post–prostatic massage voided urine. This simpler method has a 100% positive and 96% negative predictive value.