What is genitourinary chlamydia infection?
Genitourinary chlamydia infection, or chlamydiasis, is a sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis with its serotypes D–K. It is often just called 'chlamydia'.
C. trachomatis serotypes L1–L3 cause lymphogranuloma venereum, which is discussed separately.
Chlamydia stain
Who gets genitourinary chlamydia infection?
Genitourinary chlamydia infection is a very common STI.
Risk factors include:
- Being aged over 25 years old
- New or multiple sexual partners
- Inconsistent use of condoms.
What are the clinical features of genitourinary chlamydia infection?
A genitourinary chlamydia infection may cause very mild symptoms or no symptoms at all; it is asymptomatic in approximately 70% of infected women and 50% of infected men.
In men, the most common signs and symptoms of genitourinary chlamydia infection are:
- Discharge from the urethra
- Urethral irritation
- Pain on urination
- Testicular swelling or pain.
In women, the most common signs and symptoms of genitourinary chlamydia infection are:
- Abnormal vaginal discharge
- Pain on urination
- Abnormal vaginal bleeding (eg, bleeding between periods or after sex)
- Lower abdominal pain
- Dyspareunia (painful sex).
What are the complications of genitourinary chlamydia?
Genitourinary chlamydia infection can lead to complications of variable severity and duration, particularly when following multiple infections over time.
The possible complications of genitourinary chlamydia infection in men include:
- Rectal chlamydia infection, which is usually asymptomatic and occurs in men who have sex with men (MSM)
- Epididymo-orchitis
- Sexually acquired reactive arthritis
- Perihepatitis (rare in men)
- Chronic pain syndrome
- Sexually acquired conjunctivitis
- Balanitis (rash affecting glan penis)
- Infertility.
The possible complications of genitourinary chlamydia infection in women include:
- Rectal chlamydia infection due to anal sex
- Pelvic inflammatory disease
- Tubal infertility
- Ectopic pregnancy
- Sexually acquired reactive arthritis
- Sexually acquired conjunctivitis
- Perihepatitis syndrome (Fitz-Hugh-Curtis syndrome)
- Chronic pelvic pain
- A triad of reactive arthropathy, conjunctivitis, and urethritis.
Mother-to-child transmission can result in chlamydial conjunctivitis and pneumonia in newborn babies.
How is genitourinary chlamydia infection diagnosed?
In symptomatic individuals with genitourinary chlamydia infection, examination findings may include urethral discharge, abnormal vaginal discharge, cervicitis (inflammation of the cervix) and contact bleeding, tenderness on bimanual examination (cervical excitation and pelvic adnexal tenderness), and rectal discharge. As these findings can also occur with other STIs, laboratory tests are required to confirm the diagnosis of chlamydia.
In men with suspected genitourinary chlamydia infection, clinical specimens may include:
- First void morning urine (or urine that was last voided at least an hour earlier)
- A urethral swab (this has a similar or increased sensitivity).
In women with suspected genitourinary chlamydia infection, clinical specimens may include:
- A vulvovaginal swab taken by a clinician or by the patient; this has the best sensitivity (96–98%)
- An endocervical swab from inside the cervix that is taken after the vulvovaginal swab during examination with a speculum.
A urine sample is not routinely recommended in women because the bacterial load in urine is much less than in men.
Clinical specimens at extra-genital sites
Rectal and pharyngeal swabs can be taken by a clinician or the patient. A proctoscopy (examination of the rectum) should be performed if there are rectal symptoms suggestive of chlamydia infection.
Investigations
Tests for genitourinary chlamydia infection may include:
- Chlamydia nucleic acid amplification tests (NAATs) — chlamydia NAATs may be combined with tests for Neisseria gonorrhoea (gonorrhoea) and Trichomonas vaginalis (trichomoniasis)
- Enzyme immunoassays (EIAs).
Point-of-care testing using a NAAT or EIA is not routinely used. Chlamydia cultures are not widely available, have a low sensitivity (60–80%), and are not used for throat and rectal infections.
What is the treatment of genitourinary chlamydia infection?
Individuals receiving treatment for genitourinary chlamydia infection should abstain from sex for at least 7 days.
Uncomplicated genital chlamydia infection
Treatment for uncomplicated urogenital chlamydia infection includes:
- Doxycycline 100 mg twice daily for 7 days: 98% cure
- Single-dose azithromycin 1 g: 92–97% cure.
Uncomplicated rectal chlamydia infection
Treatment for uncomplicated rectal chlamydia infection includes:
- Doxycycline 100 mg mg twice daily for 7 days
- Single-dose azithromycin 1 g followed by proof-of-cure testing.
Asymptomatic infections at extra-genital sites
Doxycycline 100 mg twice daily for 7 days is used as a treatment for asymptomatic chlamydia infection at extra-genital sites.
Note that doxycycline is contraindicated in pregnancy and azithromycin is associated with QT prolongation.
Proctitis, epididymo-orchitis, and pelvic inflammatory disease
Proctitis, epididymo-orchitis, and pelvic inflammatory disease due to chlamydia infection are treated by an extended course of empiric antimicrobial therapy while waiting for test results.
Treatment should cover other possible causes of these presentations such as gonorrhoea. Supportive measures and clinical review are required.
Other treatments
The management of chlamydia infection includes a full sexual health check to look for other STIs and the notification, treatment, and testing of sexual contacts.
If the patient is pregnant or has rectal chlamydia, a proof-of-cure test with a NAAT should be performed at least 4 weeks after the completion of treatment. If taken earlier, a false-positive result may occur due to remnant chlamydial DNA. Re-testing is recommended in 3 months as re-infection is extremely common.
How can genitourinary chlamydia infection be prevented?
As for other STIs, the risk of acquiring chlamydia infection is reduced by safe-sex practices, including limiting the number of sexual partners, using condoms, and avoiding re-infection by not having sexual contact with untreated sexual partners.
If you think you are infected, stop any sexual contact and see your usual doctor or a specialist clinician at a sexual health clinic.