Nongonococcal urethritis (NGU) is urethral inflammation caused by any of several organisms (see “Etiology”).

NGU

Nongonococcal urethritis

• The occurrence is 50% in sexually transmitted disease clinics. Chlamydia trachomatis is the most common notifiable disease in the U.S., with >1.5 million infections reported to the Centers for Disease Control and Prevention (CDC) in 2016.
• NGU most commonly affects men in a higher socioeconomic class, affecting heterosexual men more frequently than men who have sex with men.
• NGU carries a greater morbidity rate than gonococcal urethritis (GCU).

• Incubation period: 2 to 35 days.
• Symptoms: Dysuria, whitish-clear urethral discharge, and urethral itching. The onset of symptoms in NGU is less acute than in GCU. The majority of persons with C. trachomatis infection are not aware of their infection because they do not have symptoms that would prompt them to seek medical care.
• Signs: Whitish-clear urethral discharge, meatal edema, and erythema. Infected women manifest pyuria, and the disease can present as acute urethral syndrome.

• Epididymitis in men may be linked to nonbacterial prostatitis, proctitis in men who have sex with men, or Reiter syndrome.
• Urethritis complications are more common in women and can be associated with ectopic pregnancy, pelvic inflammatory disease, or infertility.

• Most common agent is Chlamydia spp., an obligate intracellular parasite possessing both DNA and RNA, which replicates by binary fission. It causes 20% to 50% of NGU cases. Two species exist:
  1. Chlamydia psittaci
  2. Chlamydia trachomatis with its 15 serotypes:
     1. Serotypes A through C cause hyperendemic-blinding trachoma.
     2. Serotypes D through K cause genital tract infection.
     3. Serotypes L1 through L3 cause lymphogranuloma venereum.
• Other causes of NGU: Mycoplasma genitalium (found in 44% of treatment failures with double infection with C. trachomatis in up to 15% of cases); Ureaplasma urealyticum, causing 15% to 30% of the cases of NGU; Trichomonas vaginalis; herpes simplex virus; and Adenovirus. However, the cause of up to 50% of the cases of NGU may not be identified.
• Asymptomatic infection occurs in 28% of the contacts of women with chlamydial cervical infection.

• Gonococcal urethritis
• Herpes simplex virus
• Trichomoniasis

• Requires demonstration of urethritis and exclusion of infection with N. gonorrhoeae.
• Nucleic acid amplification tests (NAATs) have replaced culture where persons are screened for asymptomatic genital infection, and yields more sensitivity, specificity, and ease of specimen transport than any other tests available for the diagnosis of chlamydial and gonococcal infections. NAATs should be used to detect chlamydia and gonorrhea except in cases of child sexual assault, rectal and oropharyngeal infections in prepubescent girls, and when evaluating a potential gonorrhea treatment failure, in which case culture and susceptibility testing might be required.
• Chlamydia culture: The appearance of polymorphonuclear cells on urethral smear confirms the diagnosis of urethritis. Because Chlamydia is an intracellular parasite of the columnar epithelium, the best specimen for culture is an endourethral swab taken from an area 2 to 4 cm inside the urethra. For culture, a Dacron-tipped swab is used; avoid calcium alginate or cotton swabs. The organism can only be grown in tissue culture, which is expensive.

• Partner notification: The names and contact information of all sexual partners within preceding 60 days should be gathered at the time of the visit and referred to the health department, or the patient notifies the contacts directly. Expedited partner treatment is recommended by the CDC and approved in several states. This consists of giving prescriptions to the infected patient for their partner(s) who have not been evaluated by a physician and are unlikely to seek medical care.
• Patients should abstain from intercourse for 7 days after therapy completion.
• Test of cure for NGU in pregnancy should be performed 4 wk after therapy completion and patients should be rescreened 3 mo after treatment.

Nongonococcal Urethritis (Patient Information)

Cervicitis (Related Key Topic)

Chlamydia Genital Infections (Related Key Topic)