Trichomonas vaginalis



Trichomonas vaginalis, also shortened as Trichomonas or simply “trick”, is a flagellated parasite that is sexually transmitted. A Trichomonas infection is formally called trichomoniasis, and includes vaginitis, characterized by a yellow-green colored vaginal discharge. Trichomoniasis can also present with cervicitis with the appearance of a “strawberry cervix” on speculum exam. 

Trichomonas can be diagnosed by wet mount microscopy, in which the vaginal discharge discussed earlier is prepared on a slide, revealing motile trichomonads or swimming flagellated parasites.

The first line treatment for trichomonas is metronidazole.

Key Points

  • Trichomonas vaginalis
    • Characteristics
      • Flagellated protozoan parasite
    • Transmission
      • Sexually transmitted
        • Coinfection with other STIs is common
        • Look for history of multiple sexual partners without protection
    • Presentation: Trichomoniasis
      • Vaginitis
        • Parasite infects squamous epithelium in vaginal mucosa
        • Yellow-green vaginal discharge
          • May be foul-smelling
          • Contrast vs. Gardnerella, which causes grey-white discharge
        • Itching, burning, and other discomfort may be seen
        • Vaginal pH may be elevated
      • Urethritis may be seen in men
    • Diagnosis
      • Motile trichomonads on wet mount (saline) microscopy
        • Flagellated pear-shaped or round organisms with jerky and spinning movements are seen
      • PCR/NAAT
        • Used when microscopy is inconclusive but trichomonas is still suspected
      • Strawberry cervix
        •  Bright red inflamed cervix seen on speculum exam
    • Treatment
      • Metronidazole for patient and partner
        • Tinidazole may also be used
          • Causes less GI side effects, but more expensive