Sexually Transmissible Infections in Clinical Practice

5. A Man with Urethral Discharge (1)

Alexander McMillan1, 2  


Department of Genitourinary Medicine, NHS Lothian, Edinburgh Royal Infirmary, Edinburgh, Uk


University of Edinburgh, Edinburgh, Uk

Alexander McMillanFormerly, Consultant Physician, part-time Senior Lecturer



Peter, 19-year-old man, attends you as his General Practitioner 3 days after he had noticed some pain on passing urine and a “moistness” at the tip of his penis.

Peter, 19-year-old man, attends you as his General Practitioner 3 days after he had noticed some pain on passing urine and a “moistness” at the tip of his penis.

5.1 What Additional History Would You Elicit?

The history is strongly suggestive of urethritis, and in a young man, this is usually caused by a sexually transmitted infection. It is therefore important to take a careful sexual history, as described in Case 1.

Although urinary tract infections in young men are uncommon, it is important to ask about other features that may indicate such infection. For example, has he had frequency, nocturia, urgency, or lower abdominal pain?

He tells you that his most recent sexual contact had been 4 days previously with a young Scottish woman with whom he has been in a sexual relationship for about 1 month. She is using the combined oral contraceptive pill as contraception, and he does not use condoms. He tells you that his partner is symptomless. He has had no other sexual contacts in the preceding 9 months. There is no history of frequency of micturition, nocturia, urgency, or suprapubic pain.

5.2 What Do You Do Next?

The history suggests that he may have acquired a sexually transmitted infection (STI), for example, Chlamydia trachomatis or N. gonorrhoeae, or both. The lack of symptoms in his partner is no indication that she does not have a genital tract infection. A consideration of the character of the urethral discharge may give a clue to the diagnosis. The majority of men with gonococcal urethritis have a frankly purulent discharge, whereas non-gonococcal urethritis (NGU) tends to be associated with a scant mucoid discharge. Sometimes, however, the discharge associated with urethral gonorrhoea is scant and that of NGU is profuse. Symptoms therefore may not be entirely helpful in differentiating gonococcal from non-gonococcal urethritis. The interval between the sexual contact and the development of symptoms again may give an indication of the most likely cause of urethritis – gonorrhoea has a pre-patent period of between 2 and 10 days, whereas that of chlamydial infection tends to be longer (7 days to 5 weeks). There is considerable overlap, however, and in any case Peter has had repeated sexual contact with the same partner over a 1-month period.

The preferred course of action in this case is to refer the patient to the local Sexual Health clinic where there are facilities for rapid diagnosis.

5.3 Peter Attends the Clinic. What Do You, as a Sexual Health Specialist Do Next?

It is, of course, essential to confirm the history that was given to Peter’s GP.

The next step is to undertake a physical examination. The abdomen is inspected and palpated. The external genitalia are examined as described in Case 1

There is no abdominal tenderness or guarding, and the kidneys are not palpable. The inguinal lymph nodes are neither enlarged nor tender. Both testes and epididymes are of normal size and consistency, and there is no tenderness. The skin of the shaft of the penis and the glans appear normal. There is a mucoid discharge from the urethra (Fig. 5.1 ), but neither warts nor ulceration is noted within the meatus.


Figure 5.1.

Mucoid urethral discharge.

5.4 What Investigations Would You Undertake?

Material for microscopical examination is obtained by inserting a plastic disposable inoculating loop (10 μL) into the urethra to a distance of about 2–3 cm, gently scraping the walls of the urethra, and withdrawing the loop. A smear is made on a microscope slide, stained by Gram’s method, and examined microscopically. Specimens for the detection of gonococcal and chlamydial infections are taken, and screening syphilis and HIV is offered (see Case 1).

You find an average of 20 polymorphonuclear leucocytes in the 10 microscopic fields that you inspected with the oil immersion lens (magnification ×1000). You do not see Gram-negative diplococci.

5.5 What is the Probable Diagnosis, and What is the Most Likely Causative Organism?

When more than five polymorphonuclear leucocytes are seen in two of five unselected microscopical fields (×1000 magnification), the patient is considered to have urethritis. In the absence of Gram-negative diplococci, the probable diagnosis is non-gonococcal urethritis (NGU) (see Fig. 5.2). (When the smear is unequivocally negative, as in this case, culture for N. gonorrhoeae is also negative in at least 95% of cases).


Figure 5.2.

Diagnosis of urethritis as judged by microscopy.

Up to 60% of cases of NGU are caused by C. trachomatis. The cause in the others is still uncertain, but Table 5.1 indicates some possible causes. Mycoplasma genitalium may cause a proportion of cases (possibly up to 20%); few clinics, however, test routinely for this infection. In a sizeable proportion of NGU cases, an organismal cause cannot be identified.

Table 5.1.

Causes of non-gonococcal urethritis.

Chlamydia trachomatis

Ureaplasma urealyticuma

Mycoplasma genitalium

Trichomonas vaginalis b

Herpes simplex virusc


Candida spp.c


aRole in etiology of non-gonococcal, non-chlamydial urethritis not settled.

bUncertainty about the proportion of cases caused by this protozoan, but may be up to 20%.

cUncommon (<1% of cases).

5.6 What Is Your Next Step in Management?

The results of the laboratory tests for N. gonorrhoeae and C. trachomatis are likely to be unavailable for up to 1 week, and it would be clearly unethical to withhold treatment until they are received. Treatment of chlamydial and non-chlamydial NGU is similar (Table 5.2, but see also Case 22). Azithromycin and doxycycline are equally efficacious in the treatment of chlamydial infection, with cure rates of >95%. Resistance of C. trachomatis to tetracyclines and the macrolides is rare. In many clinics azithromycin is the treatment of choice. It is given under supervision in the clinic, thereby obviating difficulties with adherence. Ofloxacin has similar efficacy to doxycycline, but it is more expensive. Studies have shown that treatment with erythromycin is less effective than the other treatment regimens, and side effects, particularly gastro-intestinal, are common, resulting in difficulties with adherence.

Table 5.2.

Treatment regimens for uncomplicated anogenital chlamydial infection and non-gonococcal urethritis.

Antimicrobial agent






Erythromycin base



1 g as a single oral dosea

100 mg by mouth twice daily for 7 days

500 mg by mouth twice daily for 10–14 days

400 mg by mouth once daily for 7 days

aIf the patient has eaten within the preceding 2 hours, administration of azithromycin capsules should be delayed. Alternatively, the drug can be given as a suspension in water.

5.7 You Opt to Give Him a Single Oral Dose of Azithromycin. What Else Do You Do?

Partner notification is essential and should be undertaken even when C. trachomatis is not detected (occasionally the infection may not be identified even when molecular methods of diagnosis are used). In the case of symptomatic men, as was so in Peter, an arbitrary cut-off period of 4 weeks is used to identify those sexual partners potentially at risk. (In symptomless individuals with chlamydial infection, an arbitrary cut-off of 6 months, or until the last sexual partner [whichever is the longer time period] is used). He is advised to abstain from vaginal, oral, and anal intercourse for 7 days after he and his partner have completed treatment. He is asked to contact a clinic nurse in 1 week’s time to discuss the results of his tests. At this time it is ensured that treatment has been well tolerated, and that he has not been at risk of re-infection.

Chlamydia trachomatis was identified in the urine specimen. N. gonorrhoeae was not detected in urethral material from Peter and serological tests for syphilis and for HIV yielded negative results. He had no adverse effects of treatment, and he has not had sexual contact in the preceding week.

5.8 Would You Offer a Test of Cure?

A test of cure following treatment for chlamydial infection is not generally undertaken, unless:

·               There had been vomiting shortly after ingestion of the azithromycin, or diarrhea had developed within a few hours of dosing.

·               There was a possibility of re-infection.

·               In the case of a woman, she is pregnant.

·               Patient requests.

As specific DNA remains detectable for several weeks after the organism is no longer viable, a test of cure has to be postponed for at least 5 weeks after completion of therapy.

5.9 What Are the Complications of Untreated Urethral Chlamydial Infection in a Man?

·               Acute epididymitis complicates an indeterminate proportion of men (see Case 13).

·               Acute conjunctivitis may result from auto-inoculation from the genital tract.

·               Reactive arthritis is a complication in just under 0.5% of cases (see Case 24).

If you find an error or have any questions, please email us at Thank you!