Chapter 84: Bacterial Vaginosis

PATIENT STORY

A 31-year-old woman presents with a malodorous vaginal discharge for 3 weeks. There is no associated vaginal itching or pain. She is married and monogamous. She admits to douching about once per month to prevent odor but it is not working this time. On examination, her discharge is visible (Figure 84-1). It is thin and off-white. Wet prep examination shows that more than 50% of the epithelial cells are clue cells (Figure 84-2). The patient is diagnosed with bacterial vaginosis and treated with oral metronidazole 500 mg bid for 7 days with good results.

INTRODUCTION

Bacterial vaginosis (BV) is a clinical syndrome resulting from alteration of the vaginal ecosystem. It is called a vaginosis, not a vaginitis, because the tissues themselves are not actually infected, but only have superficial involvement. While it is the most common cause of vaginal discharge, bacterial vaginosis generally does not result in dyspareunia, dysuria, burning, pruritus, or vaginal inflammation on its own. Women with BV are at increased risk for the acquisition of HIV, Neisseria gonorrhoeae, Chlamydia trachomatis, and herpes simplex virus (HSV)-2, and they have increased risk of complications after gynecologic surgery.^1-4

BV is associated with adverse pregnancy outcomes, including lower implantation rates,⁵ premature rupture of membranes, preterm labor, preterm birth,⁶ low birth weight,³ intra-amniotic infection, late miscarriage,⁶ postpartum fever, and postpartum endometritis. However, the only established benefit of BV therapy in pregnant women is the reduction of symptoms and signs of vaginal infection.^1,2

SYNONYMS

• Vaginal bacteriosis.

• Corynebacterium vaginale vaginosis/vaginitis.

• Gardnerella vaginalis vaginosis.

• Haemophilus vaginalis vaginitis.

• Nonspecific vaginitis.

• Anaerobic vaginosis.

EPIDEMIOLOGY

• BV is estimated to be the most prevalent cause of vaginal discharge or malodor in women presenting for care in the United States, causing 40% to 50% of vaginal discharge cases in women of childbearing age.⁶ However, more than 50% of women with BV are asymptomatic.^1,2 BV accounts for more than 10 million outpatient visits per year.⁴ The worldwide prevalence is estimated at 29% of women 14–49 years of age and in half of African-American women.⁷

ETIOLOGY AND PATHOPHYSIOLOGY

• Hydrogen peroxide–producing Lactobacillus is ...