WBR0786

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Author [[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Microbiology
Sub Category SubCategory::Reproductive
Prompt [[Prompt::A 33-year-old woman presents to the gynecology clinic for 2 weeks of vaginal itching and burning. She reports first noticing a greenish vaginal discharge 1 week ago associated with a very foul smell that did not seem to resolve completely after showers. The patient denies any previous episodes. She admits to having several sexual partners and to using barrier protection infrequently. What would you expect to observe on wet mount of a vaginal swab in this patient?]]
Answer A AnswerA::Clue cells
Answer A Explanation AnswerAExp::Clue cells are usually seen in bacterial vaginosis. They are associated with the organism Gardnerella vaginalis, clinically presenting with greyish vaginal discharge with a positive whiff test.
Answer B AnswerB::Motile trophozoites
Answer B Explanation AnswerBExp::Motile trophozoites are characteristic of Trichomonas vaginalis whith a classical presentation seen in this patient.
Answer C AnswerC::Amastigotes
Answer C Explanation AnswerCExp::Amastigotes are are usually not seen on vaginal swabs. They are seen on the blood smear of patients with leishmaniasis.
Answer D AnswerD::Mold hyphae
Answer D Explanation AnswerDExp::Pseudohyphae are seen in patients with candida infections.
Answer E AnswerE::Bacterial spores
Answer E Explanation AnswerEExp::Bacterial spores are usually not seen on vaginal swabs.
Right Answer RightAnswer::B
Explanation [[Explanation::Trichomonas vaginalis is an anaerobic protozoan, and the the causative agent of trichomoniasis, one of the most common sexually transmitted infections. As the organism only has trophozoites and no cysts, transmission occurs directly. Trichomonas usually infects the urogenital tract causing vaginitis in women and urethritis in men. A frothy thick green vaginal discharge can be seen that is typically very malodorous. Diagnosis is usually by detecting motile trophozoites on vaginal wet-mount. Treatment is with metronidazole for both partners to prevent reinfection.

Educational Objective: Diagnosis of trichomoniasis is by detection of motile trophozoites on vaginal swab.
References: Schwebke JR, Burgess D. Trichomoniasis. Clin Microbiol Rev. 2004;17(4):794-803.]]

Approved Approved::Yes
Keyword WBRKeyword::Trophozoites, WBRKeyword::Trichomonas vaginalis, WBRKeyword::Sexually transmitted infections, WBRKeyword::Sexually transmitted disease, WBRKeyword::STI, WBRKeyword::STD, WBRKeyword::Wet mount, WBRKeyword::Vaginal swab
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