OBG Management: How important is it to submit a Gram stain to the lab? Should a physician wait for these results to begin treatment?
Dr. Faro: Often, we’ll get back a diagnosis of BV on a Gram stain. I’ll then go back and find that these patients had a normal pH and large bacillary forms, which is in contradistinction to what the cytopathologist is reading. What this means is that Gram stains can be misread.
Dr. Ledger: The Gram stain is done when physicians don’t have microscopes in their offices. But there is a two-fold problem: the results come back a few days after the patient is seen, and there is a danger of misdiagnosis. I get a diagnosis of BV from a Gram stain at least once a week on patients who had normal pHs and didn’t have a positive whiff test. I think it may be identifying patients who have changes in their flora, but who don’t clinically have BV. Unfortunately, there are very few physicians who have microscopes or pH paper in their offices. Often, women will be treated for a yeast infection. In that situation, a Gram stain would be more useful. The bottom line is that every Ob/Gyn should have a microscope and pH paper at his or her disposal.
Dr. Hillier: I agree. The diagnosis of BV is best made using a microscopic exam of vaginal fluid, evaluation of pH, and the whiff test. However, if a microscope is unavailable or microscopy is not interpretable, a Gram stain of vaginal fluid can be a useful test for BV. Because the test needs to be sent to a central laboratory, it is not as practical as the wet mount, pH, and whiff test, but it does have good correlation with a well-performed clinical examination. If the results are in question following the clinical evaluation, it may be prudent to delay treatment until Gram stain diagnosis is available, which should take no more than 1 working day.
OBG Management: Who should be screened and when?
Dr. Faro: I think anyone who has any type of abnormality in the lower genital tract, including complaints of discomfort, burning, itching, and odor should be screened. In addition, a patient who is going to have gynecologic surgery or vaginal surgery should be screened. Also, I screen all gravidas, but not to prevent preterm labor. A gravida who has an abnormal flora and has a cesarean is at a greater risk of developing postpartum endometritis than a gravida who has a normal flora.2
Dr. Ledger: We screen almost everyone. Screening definitely should be done if the patient is complaining of abnormal discharge or has abnormal vulvar or vaginal findings.
Dr. Hillier: Women with symptoms of vaginal discharge or odor should always be evaluated for the presence of BV and other causes of vaginitis. Screening of asymptomatic women should be undertaken for those who are planning termination of pregnancy. Randomized, placebo-controlled trials have demonstrated that treatment of asymptomatic women with BV can reduce the incidence of post-abortal PID.3 There is a consistent relationship between BV and post-hysterectomy infections, which has lead some authorities to recommend routine screening of women before planned hysterectomy.4
OBG Management: Do you recommend BV screening during an annual exam? A recent study noted that approximately 50% of women with BV are asymptomatic.
Dr. Faro: Yes. I normally perform a pH test then. If the pH is 4 and she has no symptoms, I stop right there. If the pH is more than 4, I will progress to a whiff test and a microscopic examination of the discharge just to be certain. The dilemma is when you have a lady who may be totally asymptomatic with no complaints, and you find this abnormality in her vaginal flora. Should you treat or not treat? I tend to err on the side of not treating because an altered flora does not necessarily mean BV. One of the things we’re seeing a lot of lately is group B vaginitis, if such a thing exists.
Since there is a consistent relationship between BV and post-hysterectomy infections, some authorities recommend routine pre-hysterectomy screening.
Dr. Ledger: I agree. I also see something called desquamative vaginitis. In 40% of these women, the predominant organism is a group B streptococcus. So I’m not sure whether it’s desquamative vaginitis or group B strep. One of the realities is that we see all the patients who are not getting better with their first round of treatment.
OBG Management: Gravidas at 23 to 26 weeks’ gestation with BV are 40% more likely to deliver a low-birth-weight baby. If you find that gravidas have BV early in their pregnancy, how often do you screen them thereafter?