Bacterial Vaginosis

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Bacterial vaginosis (BV)\: common cause of abnormal discharge in women of reproductive age; often asymptomatic.
Pathophysiology\: loss of normal vaginal
P r e v o t e l l a s p p ., leading to discharge changes.
Risk factors\: sexual activity (unprotected cunnilingus), STIs, new sexual partner, Afro-Caribbean ethnicity, vaginal douching,
IUD, hygiene products.
Protective factors\: barrier methods, washing with water alone, combined oral contraceptive pill.
Symptoms\: thin, white-grey,
Clinical
cells, pH >4.5,
Di
chemical irritants, foreign body.
Investigations\: high vaginal swabs, pH assessment; Hay/Ison criteria for microscopic appearance.
Management\: avoid douching, use antibiotics like oral/vaginal metronidazole or clindamycin; oral metronidazole preferred;
vaginal preparations for breastfeeding women.
Complications\: higher risk of STIs, associated with miscarriage, preterm labour, low birth weight in pregnancy.
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Introduction

Bacterial vaginosis (BV) is the most common cause of abnormal discharge in women of reproductive age.
1
Though the exact aetiology is unknown, the broad pathophysiology is that BV is caused by a loss of the normal
inhabits the vaginal canal with a simultaneous increase in anaerobic bacteria. This leads to a rise in pH and alterations in
the consistency, composition and odour of vaginal discharge.
2
Up to 84% of patients are asymptomatic and many individuals are unwilling to seek medical advice due to perceived
stigma and embarrassment surrounding vaginal health.
One study in the United States demonstrated that around 29.2% of the general female population of reproductive age had
BV at any one time, with only 15.7% being symptomatic.
3,4

Aetiology

Pathophysiology
Typically, the vagina has an acidic pH of less than 4.5. This is an ideal environment for lactobacilli to thrive (Figure 1).Figure 1. Normal vaginal
Occasionally, environmental factors can trigger a pH rise in the vaginal canal. When the pH is elevated above 4.5, the
environment becomes too hostile for lactobacilli to survive.
Once the normal
M y c o p l a s m a h o m i n i s and M o b i n c u l u s s p p . (amongst others) can begin to proliferate (Figure 2). This leads to an altered
composition of vaginal discharge, leading to changes in consistency and smell.
Figure 2. Bacterial vaginosis

Risk factors

Risk factors for BV include\:
1,3
Sexual activity\: especially unprotected cunnilingus. It is important to note that whilst BV is sexually associated, it is not a
sexually transmitted infection
Existing sexually transmitted infection (STI)\: such as chlamydia and gonorrhoea
New sexual partner
Afro-Caribbean ethnicity
Vaginal douching\: introduction of cleaning solutions into the vagina
Bubble baths, shower gels and “feminine hygiene” products
Intrauterine contraceptive device (IUD) “copper coil”
. It is not known if the intrauterine contraceptive system (such as the
“Mirena”) has the same e
Some factors have been shown to be protective for BV, these include\:
1,3
Using barrier methods during sexual activity, such as condoms and dams
Washing genitals externally with water alone
The combined oral contraceptive pillClinical features
History
Most patients with BV are asymptomatic.
If present, typical symptoms of BV may include\:
Larger volumes of vaginal discharge, occasionally requiring a panty liner to control
Discharge takes on a thin consistency compared to physiological discharge
Discharge can become white or grey in colour
O
A mild itching sensation around the vulva and vaginal entrance (less common)
A cyclical appearance of symptoms which worsen after sexual intercourse, cunnilingus or menstruation
Clinical examination
A thorough female pelvic examination should be conducted for patients with suspected BV.
Typical clinical
A thin white discharge coating the vaginal walls or the speculum
O
An alkali pH if a litmus test is used
Patients are unlikely to be tender on bimanual examination.

Di

Di
Candida (thrush)
Sexually transmitted infections (STIs)\: chlamydia, gonorrhoea, herpes simplex virus (HSV), trichomoniasis vaginalis (TV)
Physiological discharge
Pregnancy
Atrophic vaginitis\: the most likely cause of discharge changes in post-menopausal women due to a reduction in
oestrogen leading to localised irritation
Chemical irritants\: these lead to allergic vaginitis; make sure to ask about changes in body wash, laundry detergents,
lubricants and use of sex toys
Foreign body\: most commonly tampons, but also consider other objects which could have been used during sexual
intercourse or contaminants if following a sexual assault
Post gynaecological surgery
Cervical ectropion\: a physiological change associated with younger women and use of the contraceptive pill
Tumour (vulva, vagina, cervix or endometrium)\: this can be benign or malignant and will require an urgent gynae-
oncology review
Table 1. An overview of the di
BV Candida
Trichomonias
is vaginalis
Physiological
Discharge
Thin, white-
Thick, white Thin, frothy
grey
Changes
throughout
menstrual
cycle, often
clear or white
Odour Fishy Non-o
irritation
Usually none
but
occasional
burning and
itching
Vulvovaginitis
causing
itching,

swelling
Itching,
soreness and
dysuria
Nil
pH >4.5 \<4.5 >5 \<4.5

Investigations

Bedside investigations
Relevant bedside investigations for BV include\:
High vaginal swabs\: for microscopy and STI screening (NAAT)
pH assessment of discharge with litmus paper\: not routinely done in a UK clinic setting but used in Europe and in low
resource settings
The diagnosis of BV can be made based on bedside investigations using the Amsel criteria and the Hay/Ison criteria.
Amsel criteria
Using the Amsel criteria, any three out of the four criteria must be met to make a diagnosis of BV\:
6
Homogeneous discharge on clinical examination
Microscopy showing vaginal epithelial cells coated with many bacilli ("clue cells")
Vaginal pH >4.5\: assessed with litmus paper
Fishy odour on adding 10% potassium hydroxide to vaginal
Hay/Ison Criteria
The Hay/Ison criteria take into account the microscopic appearance of gram-stained vaginal smear. These criteria are
recommended by the British Association of Sexual Health and HIV (BASHH).
1
The appearance of vaginal
Grade 1 (normal)\: lactobacillus morphotypes predominate
Grade 2 (intermediate)\: mixed
present
Grade 3 (BV)\: predominantly G a r d n e r e l l a and/or M o b i l u n c u s morphotypes. Few or absent lactobacilli
Grade 4\: gram-positive bacteria predominate

Management

Conservative management
Asymptomatic individuals who are not pregnant, do not routinely require treatment as BV is usually self-limiting and
resolves after 3-7 days.
General advice for patients should include\:
Avoid vaginal douching
Avoid bubble baths, shower gel and antiseptic products near the genitals
Some patients
vaginal pessary. Research suggests this can be useful, though there is no conclusive evidence yet.
7
Medical managementMedical treatment is recommended for certain groups of individuals with BV. This includes anyone with symptoms and any
pregnant individuals, regardless of choice in continuation of pregnancy.All the following treatments are believed to be similarly e
weeks and vaginal metronidazole at 61-94%.
8
Antibiotic options
Options for treating BV include\:
Oral metronidazole 400-500 mg BD for 5-7 days
Oral metronidazole 2 g stat
Oral tinidazole 2 g stat
Oral clindamycin 300 mg BD for seven days
Metronidazole vaginal gel 0.75% OD for
Clindamycin vaginal gel 2% OD for seven days
The treatment of choice for BV is usually oral metronidazole BD. Low-dose metronidazole is safe for use in pregnancy.
However, high dose metronidazole (2g stat) should be avoided in pregnancy.
Individuals who are breastfeeding should be o
important to warn patients that the ingredients may degrade condoms, therefore extra precautions should be taken to
avoid unwanted pregnancy or STIs.

Complications

BV places patients at higher risk of acquiring and transmitting STIs, including chlamydia, gonorrhoea and HIV.
2
Although there is a high prevalence of BV infection in women with pelvic in
that BV is causative of PID.
9
In pregnancy, BV is associated with
(12.5%), low birth weight and postpartum endometritis.
12,13

References

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Bertini, Marco. B a c t e r i a l V a g i n o s i s a n d S e x u a l l y T r a n s m i t t e d D i s e a s e s \: R e l a t i o n s h i p a n d M a n a ge m e n t . T h e P r e v a l e n c e o f B a c t e r i a l V a g i n o s i s i n t h e U n i t e d S t a t e s , 2 0 0 1–2 0 0 4 ; A s s o c i a t i o n s W i t h S y m p t o m s , 2017.
S e x u a l B e h a v i o r s , a n d
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C o m p a r i s o n o f o r a l a n d v a g i n a l m e t r o n i d a z o l e f o r t r e a t m e n t o f b a c t e r i a l v a gi n o s i s i n p r e g n a n c y \: i m p a c t o n f a s t i d i o u s
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P r e v e n t i o n o f i n f e c t i o n a f t e r i n d u c e d a b o r t i o n . Achilles, Sharon. et al. 4, s.l. \: Contraception, 2011, Vol. 83.
et al. 9, s.l. \: BritishB a c t e r i a l v a g i n o s i s i n a s s o c i a t i o n w i t h s p o n t a n e o u s a b o r t i o n a n d r e c u r r e n t p r e gn a n c y l o s s e s . Gözde, Izik. et al. 3, Journal of Cytology, 2016, Vol. 33.
T h e R o l e o f B a c t e r i a l V a g i n o s i s i n P r e t e r m L a b o r . Kirchner, Je
Figure 1 and 2. Dr Graham Beards. N o r m a l a n d B V CC BY-SA]
s.l. \:

Reviewer

Dr Frances Lander
Genitourinary Medicine Registrar

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Test yourself

Contents

Introduction
Aetiology
Risk factors
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