Sexual Health
Question 65 of 180
A 21 year old man presents to the Emergency Department after being contacted by a recent sexual contact to inform him they have tested positive for chlamydia. You advise him to attend the Genitourinary Medicine (GUM) clinic. Assuming he tests positive for chlamydia what antibiotic should he be prescribed?
Answer:
- If chlamydia infection is suspected or confirmed, strongly recommend referral to a genito-urinary medicine (GUM) clinic for management. If the person declines, or is unable to attend a GUM clinic, manage in ED.
- For adults and children over the age of 13 years, prescribe doxycycline 100 mg twice daily for 7 days. If doxycycline is contraindicated or not tolerated prescribe azithromycin 1 g orally for one day, then 500 mg orally once daily for two days or erythromycin 500 mg twice daily for 10–14 days.
Chlamydia
Sexual Health
Last Updated: 12th February 2021
Genital chlamydial infection is the most commonly reported curable bacterial sexually transmitted infection (STI) in the UK.
Pathophysiology
Chlamydia is caused by the obligate intracellular bacterium Chlamydia trachomatis. Infection is primarily through penetrative sex, but can also occur via autoinoculation or splash from genital fluids. In men, it infects the urethra. In women, it infects the endocervix or urethra, or both. C. trachomatis can also infect the conjunctiva, rectum, and nasopharynx.
At least 70% of women and 50% of men infected with C. trachomatis are asymptomatic. Chlamydial infection is termed uncomplicated when the infection has not ascended to the upper genital tract. Chlamydial infection is termed complicated when the infection has spread to the upper genital tract, causing pelvic inflammatory disease (PID) in women and epididymo-orchitis in men.
Risk factors
Risk factors for chlamydia infection include:
- Age under 25 years
- A new sexual partner
- More than one sexual partner in the last year
- Lack of consistent condom use
- Social deprivation — lower educational attainment, lower occupational class, and residence in a deprived area have all been associated with higher risk of chlamydia infection
Diagnosis
- Asymptomatic people who should be tested for chlamydia include:
- Sexual partners of those with proven or suspected chlamydial infection.
- All sexually active people younger than 25 years of age, annually, or more frequently if they have changed their partner.
- All people with concerns about a sexual exposure. (If the exposure was within the last two weeks, a test should be carried out at presentation and if negative, repeated two weeks after the exposure.)
- People under the age of 25 years who have been treated for chlamydia in the previous three months.
- People who have had two or more sexual partners in the previous 12 months.
- All women seeking termination of pregnancy (TOP).
- All men and women attending genitourinary medicine clinics.
- Clinical features of chlamydia in women:
- Increased vaginal discharge.
- Post-coital or intermenstrual bleeding.
- Purulent vaginal discharge.
- Mucopurulent cervical discharge.
- Deep dyspareunia.
- Dysuria.
- Pelvic pain and tenderness.
- Cervical motion tenderness.
- Inflamed or friable cervix (which may bleed on contact).
- Symptoms of chlamydia in men:
- Dysuria.
- Mucoid or mucopurulent urethral discharge.
- Urethral discomfort/urethritis.
- Epididymo-orchitis.
- Reactive arthritis.
- Symptoms of rectal chlamydia (although usually asymptomatic):
- Anal discharge.
- Anorectal discomfort.
Investigations
- If chlamydia is suspected, samples should be taken for nucleic acid amplification tests (NAATs) to confirm the diagnosis. NAAT is also used to screen for chlamydia in asymptomatic people at high risk of chlamydia infection.
- Choice of test
- In women an endocervical or vulvovaginal swab can be taken. Alternatively, a first-catch urine (FCU) sample can be collected if the woman prefers this.
- In men: A FCU is the specimen of choice. A urethral swab is an alternative.
- Rectal swabs in symptomatic men and women can be taken 'blind' by the person or a clinician.
Management
- If chlamydia infection is suspected or confirmed, strongly recommend referral to a genito-urinary medicine (GUM) clinic for management. If the person declines, or is unable to attend a GUM clinic, manage in ED.
- In people with signs or symptoms strongly suggestive of chlamydia, start treatment without waiting for laboratory confirmation (after testing for chlamydia and other sexually transmitted infections as appropriate). Test of cure (TOC) should also be undertaken for diagnosed rectal infections.
- For adults and children over the age of 13 years, prescribe doxycycline 100 mg twice daily for 7 days. If doxycycline is contraindicated or not tolerated prescribe azithromycin 1 g orally for one day, then 500 mg orally once daily for two days or erythromycin 500 mg twice daily for 10–14 days.
- Advise that sexual intercourse (including oral sex) should be avoided until the person and their partner(s) have completed treatment (or waited 7 days after treatment with azithromycin).
- Strongly encourage all people with confirmed chlamydia infection to be screened for other sexually transmitted infections (STIs), including gonorrhoea, hepatitis B, HIV, and syphilis.
- Refer all people with confirmed chlamydia infection to a GUM clinic for partner notification.
- Consider the possibility of sexual abuse in any child or young person with chlamydia.
Complications
- Untreated infection may persist or resolve spontaneously. Clearance increases with the duration of untreated infection, with up to 50% of infections resolving within 12 months of diagnosis.
- Pelvic inflammatory disease (PID), including endometritis and salpingitis, occurs in up to 16% of women with untreated chlamydia infection. PID increases the risk of:
- Tubal infertility.
- Ectopic pregnancy.
- Chronic pelvic pain.
- Epididymo-orchitis (pain, swelling, or inflammation of the epididymis and/or testicles) can result from untreated chlamydia infection in men.
- Adult conjunctivitis can occur via autoinoculation or splash from genital fluids.
- Lymphogranuloma venereum (LGV) (infection of the lymphatic system). This is most common in men who have sex with men (MSM), with highest rates in men with HIV.
- Sexually acquired reactive arthritis (SARA) (polyarthritis of weight-bearing joints) is more common in men than women with chlamydia.
- Chlamydia in pregnancy is associated with:
- Increased risk of premature rupture of membranes, pre-term delivery, and low birth weight in the infant.
- Increased risk of intra-partum pyrexia and late post partum endometritis.
- Infections of the eyes, lungs, nasopharynx, and genitals in the neonate, due to exposure in the birth canal during delivery
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
