DIAGNOSIS — Sexually active men with dysuria should be evaluated for urethritis and its associated pathogens. The presence of urethritis can be confirmed by one of the following findings [8]:
■Mucopurulent or purulent discharge on examination
■>5 polymorphonuclear cells (PMNs) per oil immersion field from the Gram's stain of a urethral swab
■Positive leukocyte esterase ("dipstick") on first-void urine or the presence of >10 WBCs per high power field of the first-void urine.
Micturition just prior to examination may hamper detection of sexually transmitted infections. Generally, it should be avoided for at least two hours priors to obtaining specimens.
A Gram's stain specimen for examination of PMNs and any organisms can be collected from expressed penile discharge or from inside the urethra. A calcium alginate swab should be inserted gently at least 2 cm into the urethra and rotated 360 degrees, with care not to force the tip past an obstruction. The swab can then be rolled across a clean microscope slide for air drying and Gram's stain evaluation.
More than four PMNs per high power field is abnormal and is seen in 60 to 90 percent of patients with urethritis [9,10]. The presence of PMNs without any visible organisms is consistent with NGU, whereas gonococcal urethritis may be diagnosed by the demonstration of gram-negative intracellular or extracellular diplococci in the urethral exudate. Because of the specificity of the urethral Gram's stain, a confirmatory culture for gonorrhea is not necessary in men, as it is in women.
Inspection for PMNs can also be performed on the first void urine by spinning 10 to 15 milliliters of urine and examining the sediment. All men with suspected urethritis (by symptoms or the above criteria) should be tested for gonorrhea and chlamydia, which can often be copathogens.
Due to the discomfort associated with collection of urethral specimens, the preferred diagnostic tests for gonorrhea and chlamydia in most centers is a nucleic acid amplification test (NAAT) from a urine sample. (See "Genital Chlamydia trachomatis infections in men" and "Diagnosis of gonococcal infections".)
Trichomoniasis and mycoplasma infections may cause symptoms of urethritis in men, but their diagnosis is more difficult. Although wet mount preparations for trichomonas can be useful in women, microscopy is very insensitive in men [2]. Endourethral culture and cultures of the first-void urine sediment can be considered. NAATs are more expensive than culture, but have superior sensitivity for T. vaginalis, and are the preferred methods for diagnosis of trichomoniasis in men.
Patients with genital ulcers should have cultures taken for HSV and have serologic testing for syphilis. Patients presenting with STD risk factors should also be routinely be offered screening for syphilis and HIV infection. (See "Screening for sexually transmitted diseases" and "Diagnostic testing for syphilis".)
In male patients with suspected urinary tract infections, a midstream urine culture is recommended to confirm the diagnosis. Microscopic or sometimes gross hematuria is occasionally seen in urinary tract infections: white cell casts are suggestive of pyelonephritis. In one study of 422 men with symptoms of dysuria, urinary frequency, and/or urgency, a positive nitrite test had a positive predictive value of 96 percent when compared to urine culture results [11].
Acute and chronic prostatitis require careful distinction from urinary tract infections in men. The majority of men with prostatitis are diagnosed based on their clinical presentations and rectal exam findings. A urinalysis should be performed to determine the presence of pyuria. A urine culture should also be obtained in all men suspected of having acute prostatitis; Gram's stain of the urine, if positive, can be used as a guide to initial therapy. Blood cultures are recommended in patients with a history of fevers and rigors to rule out bacteremia.
■Mucopurulent or purulent discharge on examination
■>5 polymorphonuclear cells (PMNs) per oil immersion field from the Gram's stain of a urethral swab
■Positive leukocyte esterase ("dipstick") on first-void urine or the presence of >10 WBCs per high power field of the first-void urine.
Micturition just prior to examination may hamper detection of sexually transmitted infections. Generally, it should be avoided for at least two hours priors to obtaining specimens.
A Gram's stain specimen for examination of PMNs and any organisms can be collected from expressed penile discharge or from inside the urethra. A calcium alginate swab should be inserted gently at least 2 cm into the urethra and rotated 360 degrees, with care not to force the tip past an obstruction. The swab can then be rolled across a clean microscope slide for air drying and Gram's stain evaluation.
More than four PMNs per high power field is abnormal and is seen in 60 to 90 percent of patients with urethritis [9,10]. The presence of PMNs without any visible organisms is consistent with NGU, whereas gonococcal urethritis may be diagnosed by the demonstration of gram-negative intracellular or extracellular diplococci in the urethral exudate. Because of the specificity of the urethral Gram's stain, a confirmatory culture for gonorrhea is not necessary in men, as it is in women.
Inspection for PMNs can also be performed on the first void urine by spinning 10 to 15 milliliters of urine and examining the sediment. All men with suspected urethritis (by symptoms or the above criteria) should be tested for gonorrhea and chlamydia, which can often be copathogens.
Due to the discomfort associated with collection of urethral specimens, the preferred diagnostic tests for gonorrhea and chlamydia in most centers is a nucleic acid amplification test (NAAT) from a urine sample. (See "Genital Chlamydia trachomatis infections in men" and "Diagnosis of gonococcal infections".)
Trichomoniasis and mycoplasma infections may cause symptoms of urethritis in men, but their diagnosis is more difficult. Although wet mount preparations for trichomonas can be useful in women, microscopy is very insensitive in men [2]. Endourethral culture and cultures of the first-void urine sediment can be considered. NAATs are more expensive than culture, but have superior sensitivity for T. vaginalis, and are the preferred methods for diagnosis of trichomoniasis in men.
Patients with genital ulcers should have cultures taken for HSV and have serologic testing for syphilis. Patients presenting with STD risk factors should also be routinely be offered screening for syphilis and HIV infection. (See "Screening for sexually transmitted diseases" and "Diagnostic testing for syphilis".)
In male patients with suspected urinary tract infections, a midstream urine culture is recommended to confirm the diagnosis. Microscopic or sometimes gross hematuria is occasionally seen in urinary tract infections: white cell casts are suggestive of pyelonephritis. In one study of 422 men with symptoms of dysuria, urinary frequency, and/or urgency, a positive nitrite test had a positive predictive value of 96 percent when compared to urine culture results [11].
Acute and chronic prostatitis require careful distinction from urinary tract infections in men. The majority of men with prostatitis are diagnosed based on their clinical presentations and rectal exam findings. A urinalysis should be performed to determine the presence of pyuria. A urine culture should also be obtained in all men suspected of having acute prostatitis; Gram's stain of the urine, if positive, can be used as a guide to initial therapy. Blood cultures are recommended in patients with a history of fevers and rigors to rule out bacteremia.