2.5.4 Non-specific Urethritis

Grading & Level of Importance: C


W. Burgdorf, Munich; R. Woolf, J. McGrath, London
Revised by A. Salava, E. Hiltunen-Back, A. Ranki, Helsinki




Non-venereal urethritis; non-gonococcal-non-chlamydial urethritis (NGNCU).


Probably underreported or not correctly diagnosed.


The term non-specific urethritis (NSU) applies to non-gonococcal, non-chlamydial urethritis (NGNCU).

Aetiology & Pathogenesis

In many men with acute urethritis, a known pathogen is not detected. The most common organism detected is Mycoplasma genitalium, which accounts for approximately 15–40% of cases and there is a high concordance of infection in sexual partners. Other causes: Trichomonas vaginalis, adenoviruses or herpes simplex virus types 1 and 2 (HSV1-2).

Signs & Symptoms

Patients complain of clear urethral discharge, dysuria, penile tip irritation, urethral discomfort or itch, but can be asymptomatic, too. Clinical signs are often modest or missing, the presence of a mucopurulent or purulent urethral discharge or penile tip erythema can be detected on examination.


Lower and upper urethral duct .


Usually based on causative agent.

Laboratory & other workups

The diagnosis of urethritis can be confirmed by demonstrating ≥ 5 polymorphonuclear leukocytes (PMNLs) per high power microscopic field from the urethral smear. 


Not neccessary. 


Spontaneous resolution may occur; some cases are persistent/reccurrent. 


Epididymo-orchitis; Sexually acquired reactive arthritis.


Based on clinical feature, and exclusion of gonococcal and chlamydial urethritis.

Differential diagnosis

Chlamydia, gonorrhoea, genital herpes simplex, chronic pelvic pain syndrome.

Prevention & Therapy

Prevention: barrier contraception.

Infection should be treated according to the etiological findings.

Azithromycin for five days (500mg stat then 250 mg od for four days) in eradicating macrolide-susceptible M. genitalium infection. If macrolide-resistant M. genitalium is detected, moxifloxacin 400mg orally once daily for 7–14 days is recommended. Test of cure >3 weeks after treatment.

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