What is the recommended diagnosis and treatment for a female patient of reproductive age with bacterial vaginosis (BV) symptoms, such as abnormal vaginal discharge, odor, or itching?

Diagnosis and Treatment of Bacterial Vaginosis

Diagnosis

BV is diagnosed using clinical criteria requiring 3 of 4 Amsel criteria: homogeneous white vaginal discharge, vaginal pH >4.5, positive whiff test (fishy odor with 10% KOH), and >20% clue cells on microscopy 1.

• Gram stain with Nugent scoring (≥4 indicates BV) is an acceptable alternative laboratory method for diagnosis 1
• Culture of Gardnerella vaginalis is not recommended as it lacks specificity 1

First-Line Treatment for Non-Pregnant Women

Oral metronidazole 500 mg twice daily for 7 days is the preferred treatment with the highest efficacy (95% cure rate) 2.

Equally Effective First-Line Options:

• Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days provides equivalent efficacy with fewer systemic side effects 1, 2
• Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days is another first-line option, though appears slightly less efficacious than metronidazole regimens 1

Critical Patient Counseling:

• Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion due to disulfiram-like reaction risk 1, 2
• Clindamycin cream and ovules are oil-based and may weaken latex condoms and diaphragms for up to 5 days after use 1, 2

Alternative Treatment Regimens

These have lower efficacy and should be reserved for specific situations:

• Metronidazole 2g orally as single dose has reduced efficacy (84% cure rate vs 95%) but may be useful when compliance is a concern 1, 2
• Oral clindamycin 300 mg twice daily for 7 days when metronidazole cannot be used 1, 2
• Clindamycin ovules 100g intravaginally once at bedtime for 3 days 1

Treatment in Pregnancy

All symptomatic pregnant women must be tested and treated for BV due to associations with premature rupture of membranes, preterm labor, preterm birth, and postpartum endometritis 1, 2.

Recommended Pregnancy Regimen:

• Metronidazole 250 mg orally three times daily for 7 days (lower dose minimizes fetal exposure) 1, 2
• Alternative: Oral clindamycin 300 mg twice daily for 7 days 1

Critical Pregnancy Considerations:

• Avoid clindamycin vaginal cream during pregnancy - two randomized trials showed increased preterm deliveries with this formulation 1
• Systemic therapy is preferred over topical to treat possible subclinical upper genital tract infections 1
• High-risk pregnant women (prior preterm delivery) with asymptomatic BV may be screened and treated in early second trimester to reduce prematurity risk 1
• Multiple studies and meta-analyses show no teratogenic or mutagenic effects from metronidazole use in pregnancy 1

Allergy or Intolerance to Metronidazole

• Clindamycin cream or oral clindamycin is preferred for patients with metronidazole allergy or intolerance 1, 2
• Patients allergic to oral metronidazole should NOT receive metronidazole vaginally 1, 2
• Metronidazole gel may be considered for patients who do not tolerate systemic metronidazole but are not allergic 1

Partner Management

Routine treatment of male sex partners is NOT recommended - clinical trials demonstrate that partner treatment does not affect a woman's response to therapy or reduce recurrence rates 1, 2.

Follow-Up

• Follow-up visits are unnecessary if symptoms resolve 1, 2
• Recurrence is common; patients should return if symptoms recur and may be treated with another recommended regimen 1
• No long-term maintenance regimen is recommended 1

Special Clinical Situations

Before Invasive Procedures:

• Screen and treat women with symptomatic or asymptomatic BV before surgical abortion - treatment with metronidazole substantially reduces post-abortion PID by 10-75% 1
• Consider screening before hysterectomy, as treatment reduces postoperative infectious complications including vaginal cuff cellulitis and endometritis 1
• More data needed before routinely treating asymptomatic BV before other invasive procedures (IUD placement, endometrial biopsy, hysterosalpingography) 1

HIV-Infected Patients:

• Patients with HIV and BV receive the same treatment regimens as HIV-negative patients 1, 2

Breastfeeding Women:

• Standard CDC guidelines apply, as metronidazole is compatible with breastfeeding 2
• Small amounts excreted in breast milk are not significant enough to harm infants 2
• Intravaginal preparations result in minimal systemic absorption (<2% of oral dose serum concentrations) 2

Common Pitfalls to Avoid

• Do not use single-dose metronidazole 2g for symptomatic disease with extensive symptoms - the 84% cure rate may be insufficient 2, 3
• Do not assume BV is always symptomatic - up to 50% of cases are asymptomatic 4
• Do not treat asymptomatic BV in low-risk pregnant women - treatment is only indicated for symptomatic disease or high-risk patients 1
• Do not use clindamycin vaginal cream in pregnancy due to increased adverse neonatal outcomes 1