Bacterial Vaginosis: Symptoms and Treatment
Symptoms and Diagnosis
Bacterial vaginosis presents with characteristic symptoms that can be diagnosed using Amsel's criteria, requiring at least 3 of 4 clinical findings. 1
Classic Symptoms
- Homogeneous, white, non-inflammatory vaginal discharge that adheres to the vaginal walls 1, 2
- Fishy vaginal odor, particularly noticeable before or after addition of 10% KOH solution (positive "whiff test") 1, 3
- Many women (>50%) remain completely asymptomatic despite having the condition 4
Diagnostic Criteria (Amsel's Criteria)
The CDC requires at least 3 of the following 4 findings for diagnosis: 1, 2
- Homogeneous white discharge
- Clue cells on microscopic examination (vaginal epithelial cells with bacteria adhered to their surface, creating stippled appearance with obscured borders) 3
- Vaginal pH greater than 4.5 1, 2
- Positive whiff test (fishy odor) 1, 3
First-Line Treatment
The CDC recommends metronidazole 500 mg orally twice daily for 7 days as first-line therapy, achieving a 95% cure rate. 1
Recommended Regimens
- Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) - preferred regimen 1, 2
- Metronidazole gel 0.75% intravaginally once daily for 5 days - alternative topical option 1, 2
- Clindamycin cream 2% intravaginally at bedtime for 7 days - alternative for metronidazole intolerance 1, 2
Alternative Regimens (Lower Efficacy)
- Metronidazole 2g orally as single dose (84% cure rate) - useful when compliance is a concern 2, 3
- Clindamycin 300 mg orally twice daily for 7 days 2
- Tinidazole 2g once daily for 2 days or 1g once daily for 5 days - FDA-approved alternative with therapeutic cure rates of 27.4% and 36.8% respectively 5
Critical Treatment Considerations
Medication Warnings
- Patients must avoid alcohol during metronidazole treatment and for 24 hours afterward due to potential disulfiram-like reaction 1, 2
- Clindamycin cream is oil-based and may weaken latex condoms and diaphragms 2
Who Should Be Treated
- All symptomatic women require treatment regardless of pregnancy status 1, 2
- Pregnant women with symptomatic BV must be treated due to association with preterm birth and adverse pregnancy outcomes 1
- High-risk pregnant women (history of preterm delivery) with asymptomatic BV may benefit from treatment 1, 2
- Before surgical abortion procedures - treatment substantially reduces post-abortion pelvic inflammatory disease 2, 3
- Before hysterectomy or invasive gynecological procedures - reduces postoperative infectious complications 2
Who Should NOT Be Treated
- Asymptomatic women with indeterminate or positive results should not be treated unless they fall into high-risk categories above 2
- Male sex partners should NOT be treated - this has not been shown to prevent recurrence or alter clinical course 1, 2
Common Pitfalls and Recurrence
High Recurrence Rates
- 50-80% of women experience recurrence within one year of completing antibiotic treatment 6, 7
- Recurrence may be due to biofilm formation protecting bacteria from antimicrobials, failure of beneficial Lactobacillus recolonization, or antibiotic resistance 6, 8, 7
Management of Recurrent BV
- Extended metronidazole course: 500 mg twice daily for 10-14 days for recurrent disease 7
- If ineffective, metronidazole gel 0.75% for 10 days, then twice weekly for 3-6 months as suppressive therapy 7
Clinical Pitfalls to Avoid
- Treating asymptomatic women unnecessarily exposes them to medication side effects without clear benefit 2
- Failing to treat before invasive procedures increases risk of post-procedure infections 2, 3
- Using single-dose regimens when compliance is not an issue - the 7-day regimen has superior cure rates (95% vs 84%) 1, 3