Trichomoniasis — DTM&H MCQ

Correct answer: C — Single-dose metronidazole 2 g orally for both partners

The correct answer is C, single-dose metronidazole 2 g orally for both partners. Trichomonas vaginalis is a sexually transmitted protozoan, and the motile flagellated organisms on wet mount are diagnostic; up to a third of infected men are asymptomatic carriers, so partner treatment is mandatory regardless of symptoms to achieve cure and prevent ping-pong reinfection. BASHH national guidance on the management of Trichomonas vaginalis recommends nitroimidazole therapy, with a 2 g single dose of metronidazole offering equivalent efficacy to the extended regimen and superior compliance, making it the preferred option when concurrent partner treatment is required. Because trichomoniasis is sexually transmitted, both partners must be treated simultaneously and sexual intercourse avoided until treatment is complete and symptoms have resolved. Why the other options are wrong: A. Metronidazole 400 mg twice daily for 7 days for the woman only: this regimen is a valid alternative dosing schedule but treating the woman alone ignores the near-certainty of an infected, asymptomatic male partner, leading to reinfection. D. Topical clotrimazole pessary for the woman: clotrimazole is an antifungal used for vulvovaginal candidiasis, which presents with thick white non-offensive discharge, not the frothy greenish discharge and motile flagellates seen here. E. Oral fluconazole 150 mg for both partners: fluconazole is also antifungal, active against Candida, and has no activity against protozoa such as Trichomonas vaginalis. B. Doxycycline 100 mg twice daily for 7 days for both: doxycycline is first-line for Chlamydia trachomatis, not for trichomoniasis, and has no useful activity against motile protozoal organisms. Key point: Motile flagellated organisms on wet mount confirm Trichomonas vaginalis, which requires nitroimidazole treatment of both partners simultaneously, irrespective of the partner's symptoms, to prevent reinfection.

Reference: BASHH, United Kingdom National Guideline on the Management of Trichomonas vaginalis (2021), International Journal of STD & AIDS, https://journals.sagepub.com/doi/10.1177/09564624221103035