Grand Rounds: Taking the guesswork out of diagnosing and managing vaginitis

April 1, 2005

An expert shares ways to avoid misdiagnosing vulvovaginal infections by becoming better acquainted with the microscopy of vaginal secretions, routinely using both pH paper and the amine test, and prudently employing vaginal yeast and Trichomonas cultures.

Vaginal discharge, itching, irritation, malodor. No doubt you've lost track of the number of patients who have presented with these complaints over the years. Unfortunately, many of these women misdiagnose themselves, turning to over-the-counter drugs.1 What's more, even a clinician's diagnosis is often dead wrong if he or she fails to confirm it with laboratory studies.2

There's growing concern over physicians' inability to accurately diagnose vulvovaginal infections, either due to their indifference toward using available office-based diagnostic tests or a lack of skill in microscopy.3 What should be a straightforward model for the evaluation and management of a patient complaint-resulting in a reliable diagnosis and effective therapy-often becomes a guessing game that leads to misdiagnosis and inappropriate treatment.

But the good news is that, in most cases, you can confirm an accurate diagnosis if you've had sufficient medical training in the microscopy of vaginal secretions, routinely use both pH paper and the amine test-and back that up with prudent use of vaginal yeast and Trichomonas cultures. In addition, be sure to test certain patients for chlamydia and gonorrhea-namely, adolescent women and those younger than 25 who have risk factors (e.g., new sex partner, multiple sex partners).

The wet mount exam plays a key diagnostic role True, no symptom has enough predictive power to allow you to confidently diagnose any of the three main causes of vaginitis. But that being said, symptoms and signs can suggest a particular diagnosis. The wet mount examination remains the best way to make a diagnosis.

A speculum exam is necessary to visualize the cervix and vagina and to obtain specimens from the endocervix to test for chlamydia and gonorrhea. However, given the rather poor sensitivity of mucopus in detecting chlamydial or gonococcal endocervicitis-or both-and the poor specificity of discharge characteristics in distinguishing between vaginitis diagnoses, you could probably forgo this step and either obtain a vaginal specimen yourself for pH testing, microscopic examination, and nucleic acid amplification testing (NAAT)-or have the patient obtain it.

Advance two cotton swabs about 8 cm into the vagina. Use one swab to apply the vaginal secretions to pH paper (colorpHast, pH 4.0-7.0) and place the other in a test tube containing 0.5 mL of saline. Agitation will result in an evenly distributed solution. From that, decant a drop onto a microscope slide. You can examine this microscopically to determine the presence of clue cells, motile trichomonads, and/or fungal elements (pseudohyphae or budding yeasts). At this point, add 10% potassium hydroxide (KOH) to the remaining secretions in the test tube and perform a whiff test. If fungal elements were not detected on saline wet mount, the KOH slide can be made as above and inspected for fungal elements. You can send a third vaginally obtained swab for NAAT for chlamydia and gonorrhea.

What pH reveals. Determining vaginal pH is an important part of evaluating the vaginal secretions of a patient with lower genital tract complaints. A normal pH (<4.5) essentially rules out the diagnosis of BV and should prompt the examiner to look carefully for fungal elements and consider the possibility that the evaluation may be normal. A pH above 4.5 suggests BV, trichomoniasis, or mucopurulent endocervicitis (MPC). BV in its pure form is not associated with inflammation (vaginosis not vaginitis). A finding of leukorrhea (more than one leukocyte per epithelial cell) should prompt you to look carefully for motile trichomonads and consider the diagnosis of concurrent MPC.