This woman presents with positive whiff test and microscopy demonstrating clue cells, suggestive of bacterial vaginosis (BV), caused by Gardnerella vagnialis.
The normal vagina is colonized by a mixture of bacteria. The pH of the vagina is usually acidic in part due to the presence of lactobacilli. However, changes in pH can lead to a change in bacterial flora. In particular, overgrowth of G. vaginalis, a gram negative rod, can lead to bacterial vaginosis (BV). Microscopy of a vaginal swab will show "clue cells," which are squamous cells with many bacteria adherent to them.
Majeroni reviews BV. BV is diagnosed by three clinical and microscopic findings. Most commonly, the clinical symptom of thin, malodorous discharge is present. It is often described as having a "fishy" odor. The pH of the discharge is usually elevated (pH > 4.5). Finally, the presence of clue cells, as described above, is important diagnostically.
Hainer and Gibson review BV and treatment. Many randomized controlled trials have shown both clindamycin and metronidazole to be effective treatments for BV. Metronidazole is usually the preferred treatment, and is typically administered in 500mg doses BID for one week. A single dose was previously used for treatment, but is no longer recommended. Metronidazole is also effective in treating trichomoniasis.
Figure A depicts clue cells. Illustration A shows a wet mount of a vaginal swab. The slide shows a clue cell in the lower left, with two normal appearing epithelial cells on the right for comparison. Illustration B depicts trichomonads, which can cause vaginitis. Illustration C depicts candida, which can also cause vaginitis. The linked video provides a brief discussion of the presentation and management of BV.
Answer 1: Trichomonas vaginalis is the causative agent in trichomonal vaginitis, which presents with greenish discharge, and significant pruritis.
Answer 2: Candida albicans is the causative agent in vulvovaginal candidiasis, which can present with thick, white, curd-like discharge.
Answer 3: Escherichia coli is a common causative agent of urinary tract infections (UTI).
Answer 5: Neisseria gonorrhoeae is the causative agent in gonoccocal urethritis and may lead to cervicitis or pelvic inflammatory disease (PID).
Majeroni BA. Bacterial vaginosis: an update. Am Fam Physician. 1998 Mar 15;57(6):1285-9, 1291.
PMID:9531911 (Link to Abstract)
Hainer BL, Gibson MV. Vaginitis. Am Fam Physician. 2011 Apr 1;83(7):807-15.
PMID:21524046 (Link to Abstract)