Vaginal Candidiasis

Bacterial vaginosis

Bacterial vaginosis (BV) describes an overgrowth of predominately anaerobic organisms such as

Gardnerella vaginalis. This leads to a consequent fall in lactic acid producing aerobic lactobacilli resulting in a raised vaginal pH.

Whilst BV is not a sexually transmitted infection it is seen almost exclusively in sexually active women.

Features

• vaginal discharge: 'fishy', offensive
• asymptomatic in 50%

Amsel's criteria for diagnosis of BV - 3 of the following 4 points should be present

1. thin, white homogenous discharge
2. clue cells on microscopy: stippled vaginal epithelial cells
3. vaginal pH > 4.5
4. positive whiff test (addition of potassium hydroxide results in fishy odour)

Management

• if the woman is asymptomatic, treatment is not usually required
  • e.g. picked up on a swab done for different reasons
  • exceptions include if a woman is undergoing a termination of pregnancy
• if symptomatic: oral metronidazole for 5-7 days
  • 70-80% initial cure rate
  • relapse rate > 50% within 3 months
  • a single oral dose of metronidazole 2g may be used if adherence may be an issue
  • the BNF suggests topical metronidazole or topical clindamycin as alternatives
• if pregnant
  • results in an increased risk of preterm labour, low birth weight and chorioamnionitis, late miscarriage
  • it was previously taught that oral metronidazole should be avoided in the first trimester and topical clindamycin used instead. Recent guidelines however recommend that oral metronidazole is used throughout pregnancy
  • if asymptomatic: discuss with the woman's obstetrician if treatment is indicated
  • if symptomatic: either oral metronidazole for 5-7 days or topical treatment. The higher, stat dose of metronidazole mentioned above is not recommended

Comparison of bacterial vaginosis and Trichomonas vaginalis © Image used on license from PathoPic