Aetiology

The majority of non gonococcal urethritis is a result of infection with

• Chlamydia Trachomatis – more likely to be seen in younger patients
• Mycoplasma genitalium – causes more symptoms (1)

Both organisms seldom coexist in the same individual. In around 30-80% of NGU patients neither C. trachomatis nor M. genitalium can be detected (1)

Other aetiological factors include:

• Trichomonas vaginalis
  • more common in non-white ethnic groups
  • isolation is greater in men >30 years
• bacterial infections, e.g. Ureaplasma urealyticum which may account for 5%–10% of cases of acute NGU
• upper urinary tract infections – 6 % of cases
• herpes simplex – less common 2-3%
• Adenovirus – seen in 2-4% of symptomatic patients, conjunctivitis is often seen in these patients as well
• rarely N. meningitidis, Haemophilus sp., Candida sp., urethral stricture and foreign bodies
• condyloma accuminata
• trauma - mechanical or chemical
• cancer of the penis
• primary syphilis
• upper urinary tract abnormalities (1,2)

Reference:

1. Horner P et al. 2015 UK National Guideline on the management of non-gonococcal urethritis. Int J STD AIDS. 2016;27(2):85-96.
2. British Association for Sexual Health and HIV. 2007 UK National Guideline on the Management of Nongonococcal Urethritis