MKSAP Quiz: 2-week history of vaginal discharge, itching
A 46-year-old woman is evaluated for a 2-week history of vaginal discharge and itching. She reports no other vaginal or urinary symptoms. She is sexually active with one male partner. She has a levonorgestrel-releasing intrauterine device for contraception. Following a physical exam and lab studies, what is the most appropriate treatment?
A 46-year-old woman is evaluated for a 2-week history of vaginal discharge and itching. She reports no other vaginal or urinary symptoms. She is sexually active with one male partner. She has a levonorgestrel-releasing intrauterine device for contraception. Medical history is otherwise unremarkable, and she takes no medications.
Speculum examination shows gray frothy discharge. The cervix is normal appearing, without purulent discharge. Bimanual examination is unremarkable.
Laboratory studies reveal a vaginal pH of 5.0. There are no hyphae on potassium hydroxide preparation. Trichomonad nucleic acid amplification test result is positive. A pregnancy test result is negative.
Which of the following is the most appropriate treatment?
A. Oral azithromycin
B. Oral fluconazole
C. Oral metronidazole
D. Topical metronidazole gel
MKSAP Answer and Critique
The correct answer is C. Oral metronidazole. This content is available to MKSAP subscribers as Question 85 in the General Internal Medicine 2 section. More information about MKSAP is available online.
The most appropriate treatment is metronidazole, 500 mg orally twice daily for 7 days (Option C). Vaginal trichomoniasis is a sexually transmitted infection (STI). Patients can be asymptomatic or present with pale yellow, green, or gray frothy vaginal discharge with itching and burning. Although trichomoniasis can be diagnosed with microscopy when motile trichomonads are noted on wet mount, nucleic acid amplification testing (NAAT) is recommended because it can be difficult to establish the diagnosis with a wet mount. Because trichomoniasis is sexually transmitted, patients should be screened for other STIs, including chlamydia, gonorrhea, HIV, and syphilis. It is also important to treat the patient's partner to help prevent reinfection and spread of infection to other sexual contacts. For women, the recommended regimen for trichomoniasis is metronidazole, 500 mg orally twice daily for 7 days. For men, the recommended treatment is metronidazole, 2 g orally in a single dose. Patients should also be retested for Trichomonas in 3 months with NAAT because of high reinfection rates.
A single 1-g dose of oral azithromycin (Option A) is appropriate treatment for chlamydia but does not treat trichomoniasis. Testing for chlamydia is appropriate in this setting because trichomoniasis is a STI, but treatment should be limited to patients with established chlamydia infection.
Fluconazole (Option B), 150 mg orally, is an appropriate treatment for vulvovaginal candidiasis but is not appropriate for the treatment of trichomoniasis. Vulvovaginal candidiasis is typically characterized by vaginal itching, irritation, and discharge. Examination reveals vulvar edema and excoriation, with thick, white, curdy vaginal discharge. Diagnostic testing involves 10% potassium hydroxide wet mount of the discharge showing yeast, hyphae, or pseudohyphae or a positive NAAT. Vulvovaginal candidiasis is not an STI; there is no need to treat partners of women diagnosed with vulvovaginal candidiasis.
Topical metronidazole vaginal gel (Option D), 5 g daily for 5 days, is an effective option for the treatment of bacterial vaginosis. This form of metronidazole, however, is not curative and is inferior to a single 2-g dose of oral metronidazole or tinidazole for the treatment of trichomoniasis.
Key Points
- The recommended regimen for trichomoniasis for women is metronidazole, 500 mg orally twice daily for 7 days; metronidazole, 2 g orally in a single dose, is the recommended regimen for men.
- Women treated for trichomoniasis should be retested in 3 months with a nucleic acid amplification test.