EVIDENCE-BASED ANSWER
obtain a urine culture in all men with suspected urinary tract infection (UTI), to reliably diagnose an infection (strength of recommendation [SOR]: C).
For further evaluation, ultrasonography with abdominal radiography appears at least as accurate as an intravenous pyelogram (IVP) for detecting urinary tract abnormalities such as hydronephrosis, stones, or outlet obstruction (SOR: C; single small poor-quality cohort study).
Imaging of the urinary tract is not supported by the literature, for low-risk males <45 years of age after their first UTI (SOR: C; expert opinion, very small cohort study). unfortunately, there is scant literature, mostly of poor quality, to guide decisions on work-up of men with a suspected UTI.
Clinical commentary
Imaging not likely to enlighten
Peter C. Smith, MD
University of Colorado Health Sciences Center
The vast majority of men with a first UTI in my practice have a preexisting, well-defined risk factor, such as a chronic indwelling catheter, immune compromise, or known prostatic hypertrophy. In otherwise healthy men with symptoms suggestive of UTI, the first order of business is to make the correct diagnosis: Is it cystitis? Pyelonephritis? Urethritis? Prostatitis?
Some of you may be surprised by the recommendation to forgo further evaluation in the majority of males with a simple first UTI. However, the underlying cause is readily apparent in the majority, and imaging adds little to a careful history and physical exam.
The proportion of men with UTI who actually meet the low-risk criteria (younger than 50, not prostatitis or urethritis, no symptoms suggesting outflow obstruction, no hematuria, etc) is vanishingly small. only that small minority of men over 50 without an obvious cause for their infection will need more evaluation. this review conforms well to current primary care practice.
Evidence summary
Limiting further evaluation of men with a first UTI to those at increased risk (TABLE) may reduce unnecessary radiological, endoscopic, or urodynamic investigation.
Approximately 20% of all UTIs occur in men,1-3 and the lifetime prevalence is about 14%.3 The incidence in elderly men is high, often attributable to a bladder outflow obstruction.4 (For this review, the definition of UTI is limited to bacterial infections of the kidney, ureter, or bladder, and does not include urethritis, epididymitis, prostatitis, or orchitis.)
TABLE
Conditions that increase risk of urinary tract infection in men3,7,9,10
| Immunocompromised |
| Uncircumcised |
| Engaging in anal intercourse |
| Age >65 years |
| Institutional care |
| Bladder outlet obstruction |
| Anatomic functional abnormalities of the urinary tract with incomplete bladder emptying (e.g., neurogenic bladder, vesicoureteric reflux) |
| Previous urinary tract surgery |
| Recent procedures: cystoscopy, catheterization, or transrectal prostate biopsy |
Get a urine culture
A urine culture is recommended to reliably diagnose an infection and guide treatment.5
- A cohort of 66 men (mean age, 66±13 years) presenting to a VA urology clinic for procedures, dysuria, or bacteriuria had urine samples taken while voiding, as well as directly from the bladder, either via suprapubic aspiration or urethral catheterization. Using bladder cultures as a gold standard, midstream urine culture had a specificity and sensitivity of >97% at a threshold of 1000 CFU/mL.6
The usual organisms are colonic bacteria: Escherichia coli (75%), enterococci (20%), and, less commonly, Klebsiella and Proteus.4