Trichomonas vaginalis

• Trichomoniasis is a curable sexually transmitted infection (STI) caused by the protozoan Trichomonas vaginalis (TV).

  • Trichomonas is classified as a protozoan, a single celled organism with flagella
  • Lives in the urethra of men and women
  • Lives in the vagina of women
• Trichomonas can increase the risk of:

  • Contracting HIV by damaging the vaginal mucosa
  • Bacterial vaginosis
  • Cervical cancer
  • Pelvic inflammatory disease
  • Pregnancy-related complications such as preterm delivery.
• Pathophysiology:

  • Transmitted through unprotected vaginal sexual intercourse - not via oral or anal sex
  • Rarely it can be transmitted vertically from mother to baby
  • Anaerobic flagellated protozoan that can affect the female urethra, vagina and paraurethral glands and the male urethra and underneath the foreskin
  • Replicates via binary fission whilst destroying epithelial cells through direct cell contact and by the release of cytotoxins
• Risk factors:

  • Multiple sexual partners
  • Unprotected vaginal intercourse
  • A history of other STIs
  • Older women are at higher risk
• Many cases of TV infection are asymptomatic, especially in men, who often present as a partner of an infected woman. If symptomatic, signs and symptoms usually develop within 28 days following infection.
• Female symptoms:

  • Offensive vaginal odour
  • Abnormal discharge - thick/thin/frothy and yellow-green
  • Itchiness or soreness of the vulva
  • Dyspareunia
  • Dysuria
• Female signs:

  • Abnormal vaginal discharge - thick/thin/frothy and yellow-green
  • Vulvitis
  • Vaginitis
  • Strawberry cervix - punctate and papilliform appearance
• Male symptoms:

  • urethral discharge
  • Dysuria
  • Urinary frequency
  • Pain or itching around the foreskin
• Male signs:

  • Urethral discharge
  • Balanoposthitis - inflammation of the glans penis (rare)
• Investigation is with charcoal swab for microscopy, culture and sensitivity:

  • Female - high vaginal swab from posterior fornix or self-administered vaginal swab
  • Males - urethral swab or first void urine sample
• Management is with anti-protozoan antibiotics:

  • Metronidazole - 2g oral single dose or 400-500mg BD for 5-7 days
  • Should abstain from sexual intercourse whilst being treated or at least one week following the single dose
  • Test of cure is not necessary unless the patient is not responding to treatment or are re-infected
• Strawberry cervix:

  • Also called colpitis macularis
  • Caused by cervicitis secondary to infection
  • Tiny haemorrhages across the surface of the cervix
• TV in pregnancy:

  • May carry a risk of premature labour and the baby having a low birth weight
  • Infection at delivery may also predispose to maternal postpartum sepsis
  • Pregnant women are treated the same as non-pregnant women but high dose regimes are not recommended
  • Metronidazole can also affect the taste of breast milk