What are the characteristics and treatment of bacterial vaginosis?

Characteristics and Treatment of Bacterial Vaginosis

Bacterial vaginosis (BV) is characterized by a homogeneous, white, thin vaginal discharge with a fishy odor, vaginal pH >4.5, and the presence of clue cells on microscopic examination, and is best treated with metronidazole 500mg orally twice daily for 7 days as first-line therapy. 1

Diagnostic Characteristics

BV has several distinctive features that differentiate it from other vaginal infections:

• Discharge characteristics: Homogeneous, white, thin discharge (unlike the thick "cottage cheese-like" discharge of candidiasis) 1
• Odor: Fishy or musty smell, particularly noticeable after intercourse or when mixed with 10% KOH solution (positive "whiff test") 1, 2
• pH: Greater than 4.5 (normal vaginal pH is ≤4.5) 1, 2
• Microscopic findings:
  • Presence of clue cells (epithelial cells covered with bacteria) 2
  • Markedly reduced or absent Lactobacillus morphology 2
  • Predominance of Gardnerella morphotype 2
  • Absent or few white blood cells 2

It's important to rule out other common causes of vulvovaginitis including Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, Candida albicans, and Herpes simplex virus 2.

Treatment Options

First-line Treatment

• Metronidazole 500mg orally twice daily for 7 days (cure rate approximately 95%) 1

Alternative Treatments

• Metronidazole gel 0.75% intravaginally once daily for 5 days (cure rate 95%) 1
• Clindamycin cream 2% intravaginally at bedtime for 7 days 1

Treatment in Pregnancy

• First trimester: Clindamycin cream 1
• Second and third trimesters: Metronidazole (oral or gel) or clindamycin cream 1
• Asymptomatic BV in high-risk pregnant women should be evaluated for treatment to reduce prematurity risk 1

Recurrent BV Treatment

BV recurs in up to 50-80% of women within one year of treatment 3, 4. For recurrent cases:

• Extended course of metronidazole (500mg twice daily for 10-14 days) 3
• If ineffective, metronidazole vaginal gel 0.75% for 10 days, followed by twice weekly for 3-6 months 3

Clinical Significance and Complications

Untreated BV increases the risk of:

• Preterm premature rupture of membranes 1
• Preterm labor and birth (relative risk 1.4 to 6.9) 1
• Postpartum endometritis 1
• Increased susceptibility to sexually transmitted infections, including HIV 1, 4
• Pelvic inflammatory disease 1

Prevention and Risk Reduction

Several strategies may help prevent BV recurrence:

• Smoking cessation 4
• Consistent condom use 4
• Hormonal contraception 4
• For postmenopausal women: vaginal estrogen with or without lactobacillus-containing probiotics 1

Follow-up Management

• Follow-up visits are generally not necessary if symptoms resolve 1
• No long-term maintenance regimen is currently available 1
• Treatment of sexual partners is not routinely recommended 1
• All pregnant women should have a follow-up evaluation one month after completing treatment 1

Emerging Approaches

Research is exploring several promising approaches for BV management:

• Probiotics (showing improved cure rates in meta-analyses) 1, 4
• Biofilm disruption techniques 3, 4
• pH modulation 4
• Vaginal microbiome transplantation 4

Common Pitfalls to Avoid

1. Misdiagnosis: Ensure proper differentiation from other vaginal infections, particularly candidiasis which has a normal pH (≤4.5) and thick discharge 1
2. Inadequate treatment duration: Short courses may lead to treatment failure 3
3. Overlooking BV in pregnant women: Untreated BV significantly increases risks of adverse pregnancy outcomes 1
4. Failing to address recurrence: BV has high recurrence rates and may require extended treatment protocols 3, 4
5. Self-medication without proper diagnosis: OTC treatments should only be used for previously diagnosed conditions with recurrent identical symptoms 1