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Sexually transmitted infections (STIs)

  • See also 

    Vulval ulcers


      STIs are a major cause of female reproductive morbidity and have been associated with spontaneous abortion, preterm labour, and pelvic inflammatory disease (PID), ectopic pregnancy, chronic pelvic pain, and tubal-factor infertility.

      STIs are among the most common infectious diagnoses in adolescents. Any adolescent diagnosed with any STI should undergo through STI screening including:  gonorrhea, Chlamydia, trichomoniasis, syphilis and HIV and proper referral to Infectious Disease Specialist.

      50% of adolescents will be sexually active by age 18 (end of Year 12 completion).

      Sexually transmitted infections are increasing in incidence in Australian Adolescents.

      Consider screening of any young person who has been previously or is currently sexually active. Screening involved testing young females and males who are asymptomatic. In general young men are more likely to be symptomatic of infection.


      Provide a confidentiality statement, including the 3 exclusions:

      • risk of self harm/suicide
      • risk of homicide
      • suspicion of abuse

      Risk assessment including: age of onset of sexual activity, gender of partner (increased risk associated with male to male intercourse), contraceptive use, associated risk factors (in both your patient and their partners) for transmission including intravenous drug use, sex work, body piercing, tattoos and type of intercourse (anal, vaginal or oral).

      Remember to consider the risk of pregnancy and test where appropriate.

      Assess the need for emergency contraception. Please discuss with the Gynaecologist on call or gynae fellow for advice.

      Consider referral for ongoing contraceptive needs. 

      Chlamydia trachomatis:

      • 60-70% of chlamydial endocervical infections in women are asymptomatic.
      • In men, urethritis is the most common clinical presentation, representing 30-50% of all cases of nongonococcal urethritis (NGU).


      Urethral discharge is usually in the morning with mild dysuria (less copious and purulent than gonococcal)

      Women may have vaginal discharge, mid-cycle and/or post coital bleeding


      First pass urine sample for screening for Chlamydia (PCR)

      Culture, direct inmunoflourescense and nucleic acid amplification tests (NAATs) for endocervical specimen.


      Uncomplicated infection of cervix, urethra and rectum (adult doses)

      • Azithromycin 1 gr orally in a single dose or
      • Doxycycline 100 mg twice a day for 7 days (not for children <8 yrs)

      Neisseria gonorrhoeae:

      • 19-50% of asymptomatic infections in women.
      • Co-infection with Chlamydia is twice as common in women with gonorrhea 


      Vaginal discharge, mid-cycle or post coital bleeding and dysuria.


      Urine sample for screening of Neisseria Gonorrhoeae

      Culture and NAATs on endocervical specimen


      • Ceftriaxone 125 mg IM in a single dose OR
      • Cefixime 400 mg orally in a single dose OR
      • PLUS treatment for Chlamydia 


      Adolescents may be asymptomatic


      Presence of diffuse, malodorous, yellow-green vaginal discharge and vaginal itching.


      Microscopy of vaginal secretions

      Culture of vaginal secretions


      • Metronidazole 2 gr orally single dose OR
      • Metronidazole 500 mg orally twice a day for 7 days (extended course)
      • Topical therapy is not advice due to inadequate level of drug concentration found in urethral and paracervical glands.

      Pelvic inflammatory disease:

      • Polymicrobial inflammatory condition
      • Most commonly sequelae of undiagnosed or improperly treated C.trachomatis or N.gonorrhoeae infections, although non-STI related PID is an established and recognize entity.


      Presentation can range from asymptomatic to severe peritonitis and tubo-ovarian abscess formation.

      Classic PID: dull abdominal pain, fever, vaginal discharge, abnormal vaginal bleeding and symptom duration typically of 3 weeks.

      50% can present: Gastrointestinal symptoms, nausea and vomiting

      Diagnostic criteria ( CDC):

      1. Uterine or adnexal or cervical  motion tenderness on pelvic exam
      2. Fever >38.5C
      3. Cervical or vaginal mucopurulent discharge
      4. Vaginal secretions with presence of White blood cells on microscopy
      5. Elevated CRP and ESR
      6. Lab documented: N. gonorrhoeae or C. trachomatis


      Endocervical swabs


      Patients with the following criteria should be considered for admission and parenteral therapy

      1. Surgical emergencies, such as appendicitis, cannot be excluded.
      2. Pregnancy
      3. The patient does not respond clinically to oral antimicrobial therapy.
      4. The patient is unable to follow or tolerate an outpatient oral regimen.
      5. The patient has severe illness, nausea, vomiting, or high fever.
      6. The patient has a tubo-ovarian abscess.
      7. The patient is immunodeficient (eg HIV infection with low CD4 counts, immunosuppressive therapy) or has another disease.
        • Parenteral Regimen
        • Clindamycin 900 mg every 8 hrs PLUS
        • Gentamicin loading dose (2 mg/kg) followed by maintenance dose of 7.5 mg once day
        • Outpatient Oral Regimen
      • Ceftriaxone 250 mg IM in a single dose PLUS
      • Doxycycline 100 mg orally twice a day for 14 days (with or without Metronidazole 500 mg orally twice a day for 14 days).

      All patients should be referred to Gynaecology 


      • Primary infection: ulcer or chancre at the infection site
      • Secondary infection: manifestations that include, but are not limited to, skin rash, mucocutaneous lesions, and lymphadenopathy
      • Tertiary infection: cardiac or ophthalmic manifestations, auditory abnormalities, or gummatous lesions
      • Latent infections: lacking clinical manifestations are detected by serologic testing.


      Darkfield examinations and direct fluorescent antibody (DFA) tests of lesion exudate

      Nontreponemal tests : VDRL and RPR

      Treponemal tests: FTA-ABS and TP-PA]


      • Primary and secondary syphilis: Benzathine penicillin G50,000 units/kg IM, up to the adult dose of 2.4 million units in a single dose
      • Early Latent Syphilis:Benzathine penicillin G50,000 units/kg IM, up to the adult dose of 2.4 m in a single dose
      • Late Latent Syphilis or Latent Syphilis of Unknown Duration

      Benzathine penicillin G50,000 units/kg IM, up to the adult dose of 2.4 million units, administered as 3 doses at 1-week intervals (total 150,000 units/kg up to the adult total dose of 7.2 million units)

      • Tertiary syphilis: Benzathine penicillin G7.2 million units total, administered as 3 doses of 2.4 million units IM each at 1-week intervals

      All patients should be referred to Infectious Diseases 

      Prevention of STIs:

      1. Tailored patient education and counselling addressing specific risk factors and effective changes in sexual behaviour
      2. Identification of adolescents unlikely to seek health care services
      3. Effective diagnosis and treatment
      4. Appropriate evaluation and treatment of sex partners
      5. Pre-exposure vaccination of persons at risk for vaccine-preventable STIs
      6. Referral for follow up

      See also Australian STI Management Guidelines