2.5.2 Chlamydial Urethritis

Worldwide it was estimated that 127 million adults aged 15-49 years encountered a new chlamydia infection in 2020. For 2023, 27 EU/EEA Member States reported 230,199 cases of chlamydia infection, with the crude notification rate 70.4 cases per 100,000 population. Sexually active young people are at the greatest risk of getting chlamydia, and women below 24 years of age have the highest number of infections in Europe. Sexual risk behavior is an important risk factor and reinfection rates of 10-30% have been documented among young adolescents with multiple sex partners.

Chlamydial urethritis is a urogenital infection caused by Chlamydia trachomatis. It is the most common sexually transmitted infection in Europe and may cause considerable morbidity and long-term reproductive health problems, particularly in young people. Infections are often asymptomatic causing delay of diagnosis and uninterrupted transmission. Chlamydia was previously known as non-gonococcal urethritis (NGU). Some 30-50% of non-gonococcal urethritis is believed to be due to chlamydia. Chlamydia infection is predominantly transmitted sexually but may be transmitted during delivery from mother to a newborn.

Urogenital chlamydia infection is caused by strains D-K of the Chlamydia trachomatis bacterium. C. trachomatis is an intracellular Gram-negative bacterium which can cause acute eye infections, trachoma (genotypes A, B and C), genital infections and lymphogranuloma venereum (LGV) (genotypes L). The incubation period is usually 1-3 weeks.

Chlamydia infection is often asymptomatic. It is estimated that 70% of genital C. trachomatis infections in women and 50% in men are asymptomatic at the time of diagnosis. Spontaneous resolution of asymptomatic infections is possible, but many patients will at some point develop symptoms and clinical disease. Acute urethral syndrome, a condition with symptoms suggestive of lower urinary tract infection in the absence of significant bacteriuria, can be caused by C. trachomatis.

• In men symptoms like mild meatal irritation, burning sensation, dysuria, urgency and frequency of urination may appear. Mild mucoid or mucopurulent urethral discharge in the morning is less profuse than in gonorrhea. Males may complain of testicular pain and epididymitis.

• In women, chlamydial urethritis can similarly cause dysuria, urgency and frequency of urination. In women, chlamydial cervicitis can cause vaginal discharge, postcoital bleeding and abdominal pain.

• Proctitis and pharyngitis are often asymptomatic. Anorectal infection can cause anal discharge and discomfort and pharyngeal chlamydia mild sore throat. Conjunctivitis can be the result of contact with contaminated hands, or direct exposure to semen and vaginal fluids.

Nucleic acid amplification tests (NAATs) are the most sensitive and the most widely used tests for the detection of genital chlamydia. Positive NAAT result can be observed within a few days of exposure but at the latest 2 weeks later. NAATs can detect C. trachomatis in first void urine and urethral, vulvo-vaginal, cervical, pharyngeal and rectal swabs. For men, the first-void urine sample is reliable, but the patients should be instructed how to collect the sample. Point of Care Tests cannot be used for self-collected swabs and allows for self-testing outside of the clinic. Serology is not recommended for screening of anogenital C. trachomatis infections. Only invasive infections will lead to detectable levels of antibodies which might remain positive for years.

Also, asymptomatic C. trachomatis infections can cause long-term complications. Urogenital chlamydial infection might be mild in clinical picture, but the complications in men include epididymitis, epididymo- orchitis and rarely sexually acquired arthritis (SARA). In women chronic pelvic pain and infertility can be the sequelae from pelvic inflammatory disease (PID) followed by untreated C. trachomatis infection. There is no strong evidence that C. trachomatis causes infertility in men.

Chlamydia cannot be distinguished clinically from gonorrhoea or other possible causes of urethritis like Mycoplasma genitalium, Trichomonas vaginalis. Urethral Herpes simplex virus infection can also cause dysuria and meatitis.

Transmission of the infection can be prevented by barrier contraception.

Chlamydia is effectively treated with antibiotics, of which doxycycline and azithromycin have cure rates of 95%.

The European guideline recommends for uncomplicated urogenital C. trachomatis infections as the first-line treatment doxycycline 100 mg twice a day for seven days (contraindicated in pregnancy) or azithromycin 1 g as a single dose.

Patients are advised to abstain from all sexual contacts for seven days after the completion of their treatment. Tests for other STIs, like gonorrhea, syphilis and HIV should be strongly recommended. Written information about the chlamydia infection should be provided.

Test-of-cure 4 weeks after completion of therapy is not recommended routinely in patients treated with the recommended first-line regimens. However, this test should be performed in pregnant women, in patients with complicated or persisting clinical findings, with second-line treatment, and if there is a suspicion of non-compliance or re-exposure of infection. In order to control the spread of the chlamydia infection, it is important to evaluate the patient’s sex partners from a period of the preceding six months and to offer them testing and treatment.