Friendly Print preview

Non-specific urethritis (NSU)  

What is NSU?

NSU is a sexually transmitted disease (STD) and refers to any infection of the urethra except those caused by gonorrhoea. It is also called non-gonococcal urethritis and is probably the commonest STD. It is 3 times more common than gonorrhoea.

What causes NSU?

NSU is caused by a number of organisms, some of which are as yet undetected. About 50 per cent of cases are caused by the organism Chlamydia trachomatis and 5 per cent by Trichomonas vaginalis.

What are the symptoms?

The symptoms appear about 2 weeks after intercourse, although the incubation period can be as long as 12 weeks and as short as 7 days.

In men: The main symptoms (if present) are:

• a burning sensation when passing urine
• a discharge (clear, white or yellow) from the penis
• Sometimes there is no discharge, just pain. Most often the symptoms are trivial.
• The first noticeable symptom is a slight tingling or burning at the tip of the penis, usually first thing in the morning. The pain sometimes becomes quite severe. The discharge soon follows. It is usually clear at first, but if untreated can become heavier and yellowish. The infection can spread to the prostate gland and testicles.
• In some, the only symptoms are spots on the underpants or dampness under the foreskin.

In women

• In women, NSU usually causes no symptoms at all but may cause vaginal discharge. Some may notice burning on urination.
• If untreated, as is often the case, it can infect the Fallopian tubes. This is the commonest form of pelvic inflammatory disease, which can result in infertility.
• NSU is diagnosed by taking special swabs from the affected areas.

How is NSU caught and spread?

It is transmitted from one person to another during sexual intercourse. Men can pick it up through vaginal sex (often the woman carries the infection without knowing) or, less commonly, through anal or oral sex with either sex.

How is NSU treated?

NSU is treated with a 10 day course of antibiotics such as tetracycline or doxycycline. It usually responds very well to treatment, but can be slow to respond in some people and may recur in some others. About 1 in 5 patients will need more than 1 course.
It is the male who usually notices symptoms and comes for treatment. However, it is important that the sexual partner or partners are tested even if they have no symptoms. Sexual intercourse must be avoided until the infection is cleared up in both partners.

How is NSU prevented?

• Using condoms for vaginal or anal sex provides some protection and should be used with any new partner.
• Important points
• Chlamydia is a common STD.
• It sometimes causes symptoms in men.
• There may be no symptoms in women.
• It can cause infertility in women (and less commonly in men).
• It is readily treated by antibiotics.
• Treatment takes 10 days and may need repeat courses.
• All sexual partners need to be treated.
• Do not have sex until infection is cleared (both partners).
• Condoms provide protection.

Copyright 1995: John Murtagh, Professor of General Practice
Monash University, Melbourne, Australia