Introduction
Urethritis represents one of the more common syndromes seen by the general medical
officer. It consists of urethral discharge, dysuria, and evidence of a urethral
polymorphonuclear leukocytosis. It implies urethral inflammation or infection and is
usually sexually acquired.
Causative Agents
Urethritis is classified as either gonococcal urethritis (GCU) if caused by Neisseria
gonorrhoeae, or as nongonococcal urethritis (NGU) if caused by other infectious
etiologies. The term nongonococcal urethritis (NGU) is more appropriate than the older
term nonspecific urethritis (NSU), since there are specific causes for NGU. Chlamydia
trachomatis or Ureaplasma urealyticum are the most frequent causes of NGU.
Postgonococcal urethritis (PGU) is nongonococcal urethritis occurring shortly after
therapy for urethral gonorrhea and is usually due to Chlamydia trachomatis.
Gonococcal vs Non-gonococcal
Urethritis
Nongonococcal urethritis occurs more frequently than gonococcal urethritis
worldwide. Although the clinical spectrum of gonococcal urethritis and non-gonococcal
urethritis differ, there is often so much overlap that any differentiation cannot be based
reliably on clinical features alone. For example, dysuria and urethral discharge is common
in both gonococcal and non-gonococcal urethritis. However, a thick, purulent discharge
present at the meatus strongly suggests GCU, especially when spontaneous or copious. A
clear or scant urethral discharge suggests NGU. The incubation period for gonorrhea is
usually shorter than for non-gonococcal urethritis.
The majority of men with gonorrhea develop symptoms within 4 days, while those with NGU
develop symptoms within 7 to 21 days. Gonorrhea may occur as an asymptomatic infection in
1 to 10 percent of the cases in men and in as many as 50 percent of the cases in women.
Non-gonococcal urethritis may be asymptomatic in up to 25 percent of infected men (5-10
percent in young active duty men), and in over 50 percent of infected women.
Diagnosis of
Urethritis
The diagnosis of urethritis should be based upon both a physical exam and
microscopic assessment of the urethral material. It is preferable to examine the patient
at least 2 hours after micturition or before their first morning void. The patient should
provide a first morning void and the first 10 to 15 cc. of the urine is saved. It is
centrifuged so that the sediment may be analyzed microscopically under high power or oil
immersion field. The presence of 10 or more polymorphonuclear leukocytes seen under high
power is suggestive of urethritis.
Discharge Sampling
Next, any discharge present at the meatus is easily recovered for examination. If a
discharge is not present, the urethra should be gently stripped by placing the gloved
thumb along the ventral surface of the penis with the fingers above, applying gentle
pressure, and moving the thumb forward to deliver the discharge.
If no discharge is expressed from the meatus, urethral material
must be recovered by inserting a small swab into the urethra. A calcium alginate or rayon
swab on a metal shaft is recommended. Cotton swabs, particularly on wooden shafts, may be
toxic to organisms such as chlamydia. The 1 to 2mm swab tip should be inserted
approximately 1.5 to 2 inches into the urethra and then removed while being rotated.
Gonococcal Urethritis
A gram stain is prepared and a culture obtained for N. gonorrhoea, using
selective media for gonorrhea (modified Thayer-Martin, or chocolate agar). The gram stain
is examined using the oil-immersion objective of the microscope. The presence of 4 or more
polymorphonuclear leukocytes (PMNs) per oil immersion field is diagnostic for urethritis.
The presence of gram-negative, intracellular diplococci on gram stain establishes a
diagnosis of gonorrhea. If these organisms are not observed, the patient is said to have
NGU. The presence of extracellular organisms having the same morphology has no diagnostic
significance. The complete absence of PMNs argues against urethritis. This test is more
than 95 percent accurate in men with symptomatic acute urethritis.
The diagnosis of gonorrhea from the gram stain
is usually confirmed by the culture. The
growth of typical colonies that are oxidase positive and consist of gram-negative
diplococci strongly suggests gonorrhea. However, a negative culture in the face of a
positive gram stain does not rule out GCU.
Non-gonoccal Urethritis (NGU)
In contrast, the diagnosis of NGU requires the presence of urethritis in addition
to an exclusion of urethral infection due to N. gonorrhoea. Chlamydia
trachomatis causes 30 to 50 percent of cases of NGU in young adults. It is an obligate
intracellular parasite that can only be grown in specialized tissue cells, not in routine
culture medium. Coinfection with C. trachomatis and N. gonorrhoea is very
common, occurring in 10 to 35 percent of men and in 40 to 60 percent of women, and has an
effect on management strategies.
Antibiotics
There are many options in the treatment of gonococcal urethritis. A single dose of
ceftriaxone (250 mg IM) will still reliably eradicate N. gonorrhoea from patients
with uncomplicated infection. The 1 mL injection of
ceftriaxone is less painful if
reconstituted with 1% xylocaine.
Another option is Cefixime 400 mg orally once. This has a 97.1
percent cure rate.
Of the quinalones, Ofloxacin 400 mg orally, or Ciprofloxacin 500 mg
orally once have 98.4 percent and 99.8 percent cure rates, respectively. Unfortunately in
some parts of Asia widespread resistance has been noted.
Due to the high likelihood of coinfection with Chlymadia trachomatis,
and to prevent the development of postgonococcal urethritis, it is recommended that in
addition to the
ceftriaxone for GCU, a second regimen should be included which is
effective against Chlamydia. Again several options exist.
Doxycycline (100mg orally BID) for 7 days or Azithromycin 1 gram orally
once are the preferred treatments.
Erythromycin (500mg base or EES 800 mg orally QID) for 7 days. Patients
unable to tolerate this much Erythromycin can be given (250mg base or 400mg EES
orally QID) extended to 14 days.
A final option is Ofloxacin
300mg BID orally for 7 days. While Azithromycin
can be more expensive than Doxycycline, it has an advantage in that the
complete treatment can be witnessed in the medical department. This may offset the expense
of treatment failures for longer treatments. A critical part of the treatment is the
recommendation that both men and women should abstain from sexual intercourse for 7 days
after the start of therapy to prevent the spread of partially treated organisms.
Recurrent Urethritis
Persistence or recurrence of urethritis within 6 weeks of therapy occurs
more commonly when NGU is not due to Chlamydia. The persistence of urethritis should be
documented by observing PMNs on a urethral smear or urinalysis. Reinfection is the most
common cause of recurrence. A careful sexual history regarding reexposure and adequate
treatment of sexual partners is critical to the management of this condition. Careful
evaluation for untreated sexual partners is essential. Once treatment failures,
non-compliance, and re-exposure have been ruled out, a wet
prep from the urethra should be
examined for T. Vaginalis. Treatment should be with Metronidazole 2 grams orally
once plus Erythromycin 500mg base or 800 mg EES orally QID for 7 days.
The absence of PMNs suggests resolution of the infectious process but with a persistent
pain syndrome that does not require further treatment with antimicrobials. Generally, 15
to 30 percent of all persistent urethritis or dysuria is noninfectious and resolves within
6 months without therapy. Also, in this situation consider Herpes Simplex virus as a
source.
Revised by LT Todd J. May, MC, USNR, U.S. Naval Hospital Okinawa, Okinawa Japan
(1999).