Bacterial Vaginosis Flashcards
What is bacterial vaginosis?
Bacterial vaginosis (BV) refers to an overgrowth of bacteria in the vagina, specifically anaerobic bacteria. It is not a sexually transmitted infection. It is caused by a loss of the lactobacilli “friendly bacteria” in the vagina. Bacterial vaginosis can increase the risk of women developing sexually transmitted infections.
What is the role of lactobacilli in the vagina?
Lactobacilli are the main component of the healthy vaginal bacterial flora. These bacteria produce lactic acid that keeps the vaginal pH low (under 4.5). The acidic environment prevents other bacteria from overgrowing. When there are reduced numbers of lactobacilli in the vagina, the pH rises. This more alkaline environment enables anaerobic bacteria to multiply.
Other than lactobacilli, what other anaerobic bacteria are associated with bacterial vaginosis?
Examples of anaerobic bacteria associated with bacterial vaginosis are:
- Gardnerella vaginalis (most common)
- Mycoplasma hominis
- Prevotella species
What are the risk factors for bacterial vaginosis?
There are a number of factors that increase the risk of developing bacterial vaginosis:
- Multiple sexual partners (although it is not sexually transmitted)
- Excessive vaginal cleaning (douching, use of cleaning products and vaginal washes)
- Recent antibiotics
- Smoking
- Copper coil
Bacterial vaginosis occurs less frequently in women taking the combined pill or using condoms effectively.
How does bacterial vaginosis present?
The standard presenting feature of bacterial vaginosis is a fishy-smelling watery grey or white vaginal discharge. Half of women with BV are asymptomatic.
Itching, irritation and pain are not typically associated with BV and suggest an alternative cause or co-occurring infection.
A speculum examination can be performed to confirm the typical discharge, complete a high vaginal swab and exclude other causes of symptoms. Examination is not always required where the symptoms are typical, and the women is low risk of sexually transmitted infections.
How is bacterial vaginosis diagnosed?
Vaginal pH can be tested using a swab and pH paper. The normal vaginal pH is 3.5-4.5. BV occurs with a pH above 4.5.
A standard charcoal vaginal swab can be taken for microscopy. This can be a high vaginal swab taken during a speculum examination or a self-taken low vaginal swab.
Bacterial vaginosis gives “clue cells” on microscopy. Clue cells are epithelial cells from the cervix that have bacteria stuck inside them, usually Gardnerella vaginalis.
What cells are characteristic of bacterial vaginosis?
Clue cells on microscopy mean bacterial vaginosis.
Briefly describe the management of bacterial vaginosis
Asymptomatic BV does not usually require treatment. Additionally, it may resolve without treatment.
Metronidazole is the antibiotic of choice for treating bacterial vaginosis. Metronidazole specifically targets anaerobic bacteria. This is given orally, or by vaginal gel. Clindamycin is an alternative but less optimal antibiotic choice.
Always assess the risk of additional pelvic infections, with swabs for chlamydia and gonorrhoea where appropriate.
Provide advice and information about measures that can reduce the risk of further episodes of bacterial vaginosis, such as avoiding vaginal irrigation or cleaning with soaps that may disrupt the natural flora.
What antibiotic is used to treat bacterial vaginosis?
Metronidazole.
When taking metronidazole what should be avoided?
Alcohol.
Why should alcohol be avoided in bacterial vaginosis?
Alcohol and metronidazole can cause a “disulfiram-like reaction”, with nausea and vomiting, flushing and sometimes severe symptoms of shock and angioedema.
Which sexutally transmitted infections are at an increased risk in bacterial vaginosis?
Bacterial vaginosis can increase the risk of catching sexually transmitted infections, including chlamydia, gonorrhoea and HIV.
What are the complications of bacterial vaginosis in pregnancy?
It is also associated with several complications in pregnant women:
- Miscarriage
- Preterm delivery
- Premature rupture of membranes
- Chorioamnionitis
- Low birth weight
- Postpartum endometritis
