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Bacterial Vaginosis
Woman's Diagnostic Cyber Disease Profile
BV, anerobic vaginitis, nonspecific vaginitis, Gardnerella vaginitis,
haemophilis vaginitis
General
description
Inflammation of the vagina due to a bacterial infection which results in
a thin, gray-white to yellow discharge and a "musty" or "fishy" odor.
Is it common?
It is the most common cause of vaginitis explaining up to 50% of
vaginal infections.
Differentiating
features
homogeneous, thin gray-white discharge; pH of vaginal secretions is >4.5;
presence of clue cells (vaginal epithelial skin cells) covered with
bacteria;
positive whiff test (mixing KOH with vaginal secretions produces
fishy odor);
gram stain as a screening criteria may be more effective than the above clinical criteria in some situations (1, 2);
Other features
Can cause odor and some itching although not as much as with a yeast
(candida) infection. Mild vulvar irritation is present in up to 20% of
cases.
Cause
Change in bacterial flora with a loss of the normally occurring vaginal
lactobacilli and an increase in other anaerobic bacteria such as
bacteroides, peptostreptococcus, mobiluncus and mycoplasma. The vaginal
anerobic (without oxygen) to aerobic (with oxygen) bacteria ratio is 1000 to
1, normal vaginal flora is 5 to 1 ratio.
Unnecessary
studies
For the isolated or infrequent periodic episode of vaginal discharge, bacterial culture has predictive value of only 50% so it is not routinely used (3, 4), however in chronic, recurrent episodes, it may be useful to pick up less frequently occuring bacterial species such as group B or D strep or E.coli (5, 6). Routine screening does not seem to prevent normal sequelae
and routine treatment of sex partner does not seem to prevent or lessen
recurrence.
Natural history
untreated
Vaginal discharge, odor and some itching or irritation will continue.
Improvement may occur over several months. Infections tend to predispose
women to pelvic inflammatory disease, post surgical (hysterectomy)
infection, and in pregnancy, chorioamnionitis, premature rupture of
membranes, preterm delivery, neonatal sepsis, postpartum endometritis,
Goals of
therapy
(Rx)
To restore normal vaginal bacteria by inhibiting anaerobic bacteria but not
the normal vaginal lactobacilli, in order to eliminate symptoms of
discharge and odor and to prevent later sequelae.
1st choice therapy
metronidazole orally (Flagyl®) 500mg twice a day for 7 days
(95% cure); OR
clindamycin (Cleocin®) 300 mg orally twice a
day for 7 days (94% cure); OR
metronidazole vaginal cream 0.75% (Metrogel®) 1 applicator
intravaginal each day for 5 days (75% cure);
Other therapies used
metronidazole, 2000 mg orally as a single dose (4, 500mg tablets)
(84% cure);
clindamycin 2% vaginal cream, 1
applicator (5gm) intravaginal each day for 7 days (86% cure);
metronidazole vaginal cream 0.75% (Metrogel®) 1 applicator
intravaginal each day for 3 days (75% cure);
exogenous lactobacillus recolonization by vaginal tablets or
suppositories containing lactobacillus or oral tablets with
lactobacilli that recolonize the gastrointestinal tract.
Treatments to
avoid
Antibiotics with activity against lactobacilli.
Reason for Rx
choices
Metronidazole has excellent activity against anaerobes but poor
activity against lactobacilli. It's cure rate is excellent and it
also covers trichomonas vaginitis with sometimes coexists with
bacterial vaginosis.
References
-
Beckmann, CRB et al. (eds.)Obstetrics and Gynecology. 3rd edition.
Baltimore: Williams and Wilkins, 1998.
-
Sobel JD: Vaginitis. N Engl J Med 1997;337(26):1896-903.
Related Articles
Vaginal Infections and Discharge
Candida Vaginitis
Chronic Infections
Topical Treatments
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