Aetiology of urethritis can be divided into infectious or noninfectious causes.
Infectious urethritis is further divided into:
- gonococcal urethritis
- “classic” form of infective urethritis
- caused by Neisseria gonorrhoeae (1)
- non-gonococcal urethritis (NGU)
- most often caused by either Chlamydia trachomatis or Mycoplasma genitalium
- the two organisms are more likely to be detected in
- younger patients with NGU, although this association is not as strong for M genitalium
- those with a urethral discharge and/or dysuria
- C. trachomatis and M. genitalium may be less common in men who have sex with men (MSM) than heterosexual men with NGU
- M. genitalium has been associated with balano-posthitis and C. trachomatis with a circinate balanitis
- both organisms infrequently coexist in the same individual with NGU, but dual infections have been identified in up to 10% of men in some studies (2)
- less common – Trichomonas vaginalis, Gardnerella vaginalis, Ureaplasma urealyticum, herpes simplex virus (HSV), adenovirus (1)
In persistent/recurrent urethritis, aetiology is most likely to be multifactorial
- an infectious agent is identified in less than 50% of cases
- Mycoplasma genitalium is identified in 20–40%
- C. trachomatis is reported in 10%–20% of men treated with azithromycin 1g
- additionaly, U. urealyticum and T. vaginalis have also been implicated
Note:
- the term nonspecific urethritis (NSU) should be not be used since it applies to nongonococcal, nonchlamydial urethritis and may result in confusion (1)
Reference:
- Hakenberg OW et al. Urethritis in men and women. European Urology Supplements. 2017;16:144-148