Trichomonas vaginalis infection
Trichomonas vaginalis is a flagellated protozoan sexually transmitted infection that presents with malodorous frothy yellow-green discharge and a strawberry cervix but is frequently asymptomatic, especially in men. Diagnosis rests on nucleic acid amplification testing of vaginal secretions, and treatment is a single 2 g oral dose of metronidazole or tinidazole with partner treatment and retesting in 3 months for high reinfection rates.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Trichomonas vaginalis is a flagellated protozoan sexually transmitted infection (STI) that colonizes the vagina, urethra, and paraurethral glands, producing vaginitis in women and often-asymptomatic urethritis in men.
- Epidemiology
Trichomoniasis is one of the three most common causes of infectious vaginitis, alongside bacterial vaginosis and vulvovaginal candidiasis, and clinical findings alone cannot reliably distinguish among the three.
- Risk factors
Unprotected sexual intercourse with an infected or untreated partner is the dominant risk factor; men are frequently asymptomatic carriers who go undetected without partner testing.
- Pathophysiology
Trichomonas vaginalis is transmitted directly through sexual contact, with the motile trophozoite adhering to and colonizing squamous epithelium of the vagina, urethra, and paraurethral (Skene) glands; there is no cyst form.
- Clinical features
Copious, malodorous, discolored vaginal discharge (pale yellow, green, or gray, and classically frothy) is the hallmark presenting symptom when the infection is symptomatic.
- Differential diagnosis
Bacterial vaginosis: thin, homogeneous, grayish-white malodorous discharge with a positive amine (whiff) test and clue cells on saline wet mount, but no motile trichomonads; vaginal pH is also…
- Diagnosis
The diagnosis is confirmed by a positive nucleic acid amplification test (NAAT) of vaginal secretions, now the CDC-recommended and preferred method because it is substantially more sensitive than wet…
- Management
First, in a nonpregnant symptomatic adult, treat with a single 2 g oral dose of metronidazole or a single 2 g oral dose of tinidazole, which is effective therapy for established Trichomonas…
- Complications
Increased risk of HIV acquisition and transmission, related to the local inflammation and epithelial disruption caused by infection.
- Prognosis
Cure rates with single-dose metronidazole or tinidazole are high in adherent patients with concurrent partner treatment.
- Prevention
Partner treatment at the time of index case diagnosis (empiric, without waiting for partner testing) is the single most effective measure to prevent reinfection.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Chlamydia trachomatis infection
Chlamydia trachomatis is the most commonly reported bacterial sexually transmitted infection in the United States, frequently asymptomatic, and diagnosed by nucleic acid amplification testing of urine or genital/rectal/oropharyngeal swabs. Uncomplicated genital infection is treated with a single dose of azithromycin or a course of doxycycline, complications include pelvic inflammatory disease and epididymitis, and LGV serovars require a 21-day course and are an increasing cause of proctitis.
- Mycoplasma genitalium infection
Mycoplasma genitalium is an emerging sexually transmitted pathogen and a leading cause of nongonococcal, nonchlamydial urethritis in men and of cervicitis and pelvic inflammatory disease in women. Diagnosis requires nucleic acid amplification testing, and treatment is resistance-guided, with doxycycline lead-in therapy followed by extended azithromycin or moxifloxacin because macrolide resistance is increasingly common.
- Pelvic inflammatory disease
Pelvic inflammatory disease is an ascending polymicrobial infection of the upper female genital tract, most often caused by Neisseria gonorrhoeae, Chlamydia trachomatis, or Mycoplasma genitalium, diagnosed clinically on uterine, adnexal, or cervical motion tenderness. Most women are treated as outpatients with a single dose of ceftriaxone plus 14 days of doxycycline, while parenteral cefotetan or cefoxitin plus doxycycline, or clindamycin plus gentamicin, is reserved for hospitalized patients, with tubo-ovarian abscess and infertility among the major complications of delayed treatment.
- Infectious genital ulcers
Infectious genital ulcers are caused chiefly by herpes simplex virus and syphilis in the United States, with chancroid, lymphogranuloma venereum, and granuloma inguinale as less common causes, distinguished by ulcer pain, number, and associated lymphadenopathy, and worked up with an ordered panel of HSV NAAT, syphilis serology or darkfield, and targeted testing since a substantial minority of ulcers have no identified cause and empiric therapy is often required.
- Condyloma acuminata (anogenital warts)
Condyloma acuminata are soft, verrucous anogenital warts caused chiefly by human papillomavirus types 6 and 11, diagnosed clinically on inspection, and treated with patient-applied imiquimod or podofilox or provider-administered trichloroacetic acid or cryotherapy, with 9-valent HPV vaccination as the primary prevention.