A 32-year-old woman comes to the office due to a small amount of malodorous vaginal discharge. She is sexually active with a male partner and uses condoms sporadically. The patient also requests testing for all sexually transmitted diseases because she is unsure if her partner is monogamous. She drinks a glass of wine every night with dinner and has had an abnormal Pap test in the past. Speculum examination reveals thin, gray discharge. Wet mount microscopy of the discharge shows large, atypical vaginal epithelial cells and no protozoa. Application of potassium hydroxide solution to the discharge yields a strong odor. Which of the following is the best treatment option for this patient?
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This patient has bacterial vaginosis (BV), an alteration in the normal vaginal flora associated with loss of lactobacilli and overgrowth of anaerobes, particularly the gram-variable rod Gardnerella vaginalis. Although BV is not a sexually transmitted infection, it is associated with sexual activity (due to alterations of the vaginal flora from semen or contraceptives [eg, spermicide]).
Patients with BV commonly have a thin, gray or clear malodorous vaginal discharge. The discharge's odor becomes more prominent when potassium hydroxide (KOH) is added to a sample (whiff test) because of the volatilization of amines produced by G vaginalis and other anaerobes. Clue cells on wet mount microscopy are also characteristic.
Clindamycin and metronidazole are effective treatments for BV. Clindamycin is a bacteriostatic drug that inhibits protein translation by binding to the 50s ribosomal subunit. Metronidazole is bactericidal and damages the DNA of anaerobes; it is typically avoided with concurrent use of alcohol due to a disulfiram-like reaction (eg, vomiting, flushing).
(Choice A) Chlamydia trachomatis is an intracellular, gram-negative bacterium that can infect the columnar epithelium of the cervix (eg, cervicitis) and urethra, in addition to the lungs and eyes. Diagnosis is with nucleic acid amplification testing, and treatment is with azithromycin, a bacteriostatic macrolide antibiotic.
(Choice B) Neisseria gonorrhoeae is a gram-negative diplococcus that infects the genital mucosa (eg, cervicitis, urethritis) and is diagnosed with gram stain of discharge or nucleic acid amplification testing. It is treated with ceftriaxone (a third-generation cephalosporin that inhibits cell wall biosynthesis) monotherapy in the setting of negative testing for Chlamydia, and ceftriaxone plus doxycycline when Chlamydia coinfection is present.
(Choice D) Vulvovaginal candidiasis is typically due to Candida albicans, which causes vaginal pruritus, labial erythema, and a white, curd-like discharge. KOH examination shows yeast forms and pseudohyphae. Treatment is with azole antifungals (eg, fluconazole), which block ergosterol synthesis.
(Choice E) Syphilis causes a painless chancre (not vaginal discharge), followed by a rash and systemic symptoms; it is caused by the gram-negative spirochete Treponema pallidum. It is treated with penicillin, a bactericidal beta-lactam antibiotic that inhibits cell wall synthesis.
Educational objective:
Bacterial vaginosis causes a thin, gray or clear, malodorous discharge from overgrowth of anaerobes (eg, Gardnerella vaginalis) and a loss of lactobacilli in the vaginal flora. Diagnosis is confirmed by the presence of clue cells and a positive amine whiff test with potassium hydroxide. Treatment is with clindamycin or metronidazole.