Bacterial vaginosis

Background

• Is a vaginal dysbiosis resulting from replacement of the normally dominant Lactobacillus species in the vagina, with high concentrations of anaerobic bacteria.
• Is not an infection, nor is it sexually transmitted, although it is associated with sexual activity.
• Accounts for up to 50% of cases of vaginitis
• Associated with preterm labor and premature rupture of membranes

Clinical Features

• Whitish-gray vaginal discharge and odor
  • Lack of discharge makes diagnosis less likely
• May have history of "physiologic whiff test" after contact with male ejaculate which is alkaline (like KOH)

Differential Diagnosis

Vulvovaginitis

• Bacterial vaginosis
• Candida vaginitis
• Trichomonas vaginalis
• Contact vulvovaginitis
  • Bubble baths and soaps
  • Deodorants, powders, and douches
  • Clothing
• Atrophic vaginitis due to lack of estrogen (AKA Vulvovaginal atrophy)
• Lichen sclerosus
• Tinea cruris
• Chlamydia/Gonorrhea infection
• Pinworms
• Vaginal foreign body
  • Toilet paper
  • Other
• Genitourinary syndrome of menopause
• Foreign body
• Allergic reaction
• Normal physiologic discharge

Evaluation

Work-up

A "clue cell": note effacement of borders by bacteria, as compared to normal epithelial cells below.

Normal vaginal epithelial cells on wet mount: note clean borders. Presence of lactobacilli (tiny rods) is normal.

• Wet mount shows clue cells: vaginal epithelial cells with "stippled appearance" due to coverage by bacteria
• Whiff Test: fishy odor with 10% KOH prep
• CDC recommends testing all women with BV for HIV and other STDs

Diagnosis

Amsel criteria (3/4 must be present)

• Homogeneous, thin, gray-white discharge
• Positive whiff test
• Vaginal pH>4.5
• Clue cells on wet mount (at least 20% of epithelial cells)

Management

• No need to treat if asymptomatic
  • In pregnant patients, consider treating to prevent preterm birth, though evidence is conflicting
• Do NOT need to treat sexual partner
• Does not need a test of cure

Antibiotics

First Line Therapy

• Metronidazole 500 mg PO BID for 7 days OR
• Metronidazole gel 0.75%, one full applicator (5 g) intravaginally, qd for 5 days OR
• Clindamycin cream 2%, one full applicator (5 g) intravaginally qHS for 7 days

Alternative Regimin

• Tinidazole 2 g PO qd for 2 days OR
• Tinidazole 1 g PO qd for 5 days OR
• Clindamycin 300 mg PO BID for 7 days OR
• Clindamycin ovules 100 mg intravaginally qHS for 3 days (do not use if patient has used latex condom in last 72 hrs)

Pregnant

• Metronidazole 250mg PO q8h x 7 days
• Metronidazole 2g PO x 1 dose is also acceptable
• Multiple studies have not demonstrated teratogenicity from metronidazole use

Prophylaxis (Sexual Assault)

• Metronidazole 2 g PO x 1 OR
• Tinidazole 2 g PO x 1

Disposition

• Discharge

See Also

• Vulvovaginitis