Bacterial Vaginosis

Question 1

Definition

Answer 1

Bacterial vaginosis (BV) occurs due to an overgrowth of vaginal commensals = thin, white and malodourous discharge.
Sexually Associated Condition

Question 2

Epidemiology + Risk factors

Answer 2

• Black Carribean Ethnicity
• Vaginal douching
• Perfumed soaps/gels
• Receptive oral sex (cunnilingus)
• Recent change of sexual partner or multiple sexual partners
• WSW
• Smoking
• Presence of STI e.g chlamydia or herpes
• Intrauterine device

Question 3

Protective factors

Answer 3

Condom use
Circumcised male partners
Use of COCP or POP

Question 4

Pathophysiology

Answer 4

Commensals predominantly anaerobic including
- Garnerella vaginalis
- Mycoplasma homonis
- Mobiluncus sp
Associated with loss of lactic acid producing lactobacilli = responsible for maintaining normal vaginal acidity (pH 3.5-4.5)
- This results in a raised vaginal pH

Question 5

Symptoms

Answer 5

• Foul smelling ‘fishy’ vaginal odour
• Greyish-white discharge
• 50% of women asymptomatic

Question 6

Signs

Answer 6

• Thin, white, homogenous discharge lining the vaginal walls and vestibule
• Malodorous discharge
• The vagina will NOT appear inflamed or irritated

Question 7

Diagnosis

Answer 7

• Vaginal examination: Use speculum to visualise vagina + cervix.
  = a thin-white discharge lining the vaginal walls, particularly the posterior fornix
• Vaginal pH test:
  = pH >4.5 is suggestive of BV
• High vaginal swab

Question 8

Which women may not require examination

Answer 8

Examination and investigations may be omitted and empirical treatment started for women with characteristic symptoms of BV. Must fullfill several criteria however:
- Low risk STI
- Not postnatal or post-miscarriage or pre/post termination
- Not pregnant
- No other symptoms of an alternative cause of vaginal discharge

Question 9

Diagnostic criteria

Answer 9

AMSEL CRITERIA:
- Thin, white, homogeneous discharge
- Clue cells on wet mount microscopy
- pH of vaginal fluid >4.5
- Release of fishy odour on adding alkali to discharge (10% KOH, positive ‘whiff’ test)

Question 10

Hay/Ison Criteria

Answer 10

A labratory diagnosis that grades a gram-stained vaginal smear
- Grade 1: Lactobacillus morphotypes predominate (normal)
- Grade 2: mixed flora with some lactobacilli present, but Gardnerella or Mobiluncus species also present (intermediate)
- Grade 3: Predominantly Gardnerella and/or Mobiluncus morphotypes with few or absent Lactobacilli (BV confirmed)

Question 11

Treatment

Answer 11

Abx:
- Oral metronidazole: 5-7 days course of 400mg bd
(also appropriate for pregnant women).
= If adherence is an issue, offer a single 2g dose
- Topical metronidazole: 5 day course of 0.75% intravaginal metronidazole gel od, offered if topical treatment is preferred or oral treatment is not tolerated.
- Oral clindamycin or tinidazole: alternatives but are less preferred

Question 12

Prevention

Answer 12

• Block transmission: promote the use of condoms
• Oral contraception: COCP and POP use reduces the risk of BV

Question 13

Complications

Answer 13

• Increased risk of STI
• Miscarriage
• Spontaneous abortion
• Pre-term delivery and premature rupture of membranes (PROM)
• Low birth weight baby
• Post partum endometritis
• Post-cesarean wound infection