Bacterial Vaginosis

Question 1

What is bacterial vaginosis?

Answer 1

• an overgrowth of anaerobic bacteria in the vagina
• it is NOT an STI, but can increase the risk of developing an STI

Question 2

Why does bacterial vaginosis occur?

Answer 2

• lactobacilli are the main component of the healthy vaginal flora
• they produce lactic acid to keep the vaginal pH < 4.5
• the pH rises when there are reduced numbers of lactobacilli
• a more alkaline environment allows for other bacteria to grow

Question 3

What anaerobic bacteria are associated with BV?

Answer 3

• Gardnerella vaginalis (most common)
• Mycoplasma hominis
• Prevotella species

!! BV can occur alongside other infections, including STIs + candidiasis !!

Question 4

What are the risk factors for BV?

Answer 4

• multiple sexual partners
• excessive vaginal cleaning (douching / vaginal washes)
• recent antibiotics
• smoking
• copper coil

(it occurs less frequently in women taking the COCP / using condoms)

Question 5

How does BV typically present?

Answer 5

!! fishy-smelling watery grey / white vaginal discharge !!

• it does not tend to produce pain, itching / irritation
• 50% are asymptomatic

Question 6

What investigations are performed in BV?

Answer 6

speculum examination + HVS:

• confirms presence of discharge
• charcoal swab is taken for microscopy
  • this can be HVS or self-taken VVS

vaginal pH:

• tested using swab + pH paper
• pH will be > 4.5

Question 7

What is the key finding on microscopy in BV?

Answer 7

clue cells:

• epithelial cells from the cervix that have bacteria stuck inside them
• this is usually Gardnerella vaginalis

Question 8

What is the treatment for BV?

Answer 8

• asymptomatic BV does not usually require treatment
• symptomatic BV is treated with metronidazole orally or through vaginal gel
• metronidazole specifically targets anaerobic bacteria

Question 9

What other investigations may be performed in BV?

Answer 9

swabs for chlamydia / gonorrhoea if appropriate

Question 10

What additional information may be given to patients about preventing BV in the future?

Answer 10

avoiding vaginal irrigation / cleaning with soaps that may disrupt the natural flora

Question 11

When prescribing metronidazole, what advice must be given to patients?

Answer 11

!! avoid alcohol during treatment !!

• this produces a disulfiram-like reaction
• there is N&V, flushing and sometimes shock / angioedema
• avoid alcohol for 48 hours after stopping metronidazole

Question 12

What is the main risk associated with BV?

Answer 12

it increases the risk of catching sexually transmitted infections