A 20-year-old woman comes to the office due to 3 days of malodorous vaginal discharge and severe vulvar pruritus. The patient is sexually active and had a copper-containing intrauterine device placed for contraception last year. She has no chronic medical conditions and has had no surgeries. Vital signs are normal. Pelvic examination shows a thin, frothy, and green vaginal discharge with marked vulvar and vaginal erythema. Vaginal discharge pH is 5.5. The intrauterine device strings are visualized and protrude through the cervical os. Microscopic examination of this patient's vaginal discharge will most likely reveal which of the following?
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Vaginal discharge is common and normal in reproductive-age women and is related to changes in estrogen levels during the menstrual cycle. However, changes in vaginal discharge color, volume, or odor are concerning for infection; common causes include bacterial vaginosis, Candida albicans, and Trichomonas vaginalis. The appearance of vaginal discharge caused by these various etiologies may have some overlap and is not always reliable; therefore, wet mount microscopy and vaginal pH testing are performed to confirm the diagnosis.
The most likely cause of this patient's abnormal vaginal discharge is T vaginalis, a sexually transmitted infection that often presents with a malodorous, thin, frothy, yellow-green vaginal discharge. Some patients occasionally have purulent vaginal discharge, although others may be asymptomatic. The change in vaginal discharge composition results in an elevated vaginal pH (>4.5) and causes vulvovaginal inflammation, resulting in vulvar pruritus, dyspareunia, and vulvovaginal erythema. Wet mount microscopy demonstrates motile, flagellated, ovoid protozoa. Patients and their sexual partners are treated with metronidazole (even if asymptomatic) to prevent reinfection.
(Choice A) Clue cells, vaginal epithelial cells coated with Gardnerella vaginalis, are diagnostic for bacterial vaginosis. In contrast to this patient, individuals with bacterial vaginosis typically have minimal to no vulvovaginal erythema. The discharge is thin, gray-white, and has an associated "fishy" odor.
(Choice B) Actinomyces is an anaerobic bacteria that colonizes intrauterine devices and may cause pelvic inflammatory disease (eg, fever, abdominal pain, cervical motion tenderness). However, Actinomyces does not cause vaginitis and is not visualized on wet mount microscopy. A culture typically shows filamentous, gram-positive bacilli in a branching pattern.
(Choice D) Multinucleated giant cells are occasionally seen on cervical cytology (rather than microscopy) in patients with herpes simplex virus. Herpes simplex virus is a rare cause of cervicitis, but patients typically have concomitant, painful vulvovaginal vesicles.
(Choice E) Candida albicans is a common cause of vulvovaginitis and usually presents with vulvar pruritus and vulvovaginal erythema. Candida vulvovaginitis typically has an odorless, thick, white vaginal discharge that is adherent to the vaginal wall ("cottage cheese" appearance); microscopy reveals pseudohyphae.
Educational objective:
Trichomonas vaginalis is a common cause of vaginitis and typically presents with a malodorous, thin, frothy, yellow-green vaginal discharge with an elevated pH (>4.5). Wet mount microscopy reveals motile, flagellated ovoid protozoa.