Bacterial vaginosis Flashcards
What is the pathophysiology of bacterial vaginosis?
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.
What are the risk factors for BV?
Whilst BV is not a sexually transmitted infection it is seen almost exclusively in sexually active women.
What are the clincial features of BV?
vaginal discharge: ‘fishy’, offensive
asymptomatic in 50%
What criteria is used for diagnosis of BV?
AMSEL’S CRITERIA: 3 of 4 needed
- thin, white homogenous discharge
- clue cells on microscopy: stippled vaginal epithelial cells
- vaginal pH > 4.5
- positive whiff test (addition of potassium hydroxide results in fishy odour)
What is seen on microscopy in BV?
Clue cells - epithelial cells develop a stippled appearance due to being covered with bacteria
What is the management of BV?
Oral metronidazole for 5-7 days
The BNF suggests topical metronidazole or topical clindamycin as alternatives
What is the prognosis with BV?
70-80% initial cure rate
Relapse rate > 50% within 3 months
What are the similarities and differences between BV and trichomonas?
What are the complications of BV?
Infection after surgery
Pregnancy if left untreated -> results in an increased risk of preterm labour, low birth weight and chorioamnionitis, late miscarriage
Guidelines recommend treatment with oral metronidazole throughout pregnancy. The BNF still advises against the use of high dose metronidazole regimes.
Is presence of BV flora abnormal in women?
No - normal in small numbers but in larger numbers the normal lactobacillary flora of the vagina is disrupted and bacterial vaginosis occurs.
Why is presence of G. vaginalis alone not enough to diagnose BV?
It is present in 30-40% of asymptomatic women
What investigations should be done to diagnose BV?
Microscopy for “clue cells” - epithelial cells densely covered with bacilli
Positive amine test - fishy ammoniacal smell when discharge is mixed with 10% potassium hydroxide
What are the similarities and differences between BV and candida?
