Genitourinary Medicine Flashcards
What is the most common cause of abnormal discharge in women of reproductive age?
Bacterial vaginosis (BV)
It is worth remembering that BV can occur alongside other infections, including candidiasis, chlamydia and gonorrhoea.
Pathophysiology of BV?
BV is caused by a loss of the lactobacili (‘friendly bacteria’) in the vaginal canal - this can be trigged by environmental factors.
This leads to a rise in pH (more alkaline) which enables anaerobic bacteria to multiply.
This leads to alterations in the consistency, composition and odour of vaginal discharge.
What are the main component of the healthy vaginal bacterial flora?
Lactobacili
How do lactobacili keep the vaginal pH low?
They produce lactic acid
What is the ideal pH of the vaginal canal?
3.8-4.5
Give 3 examples of anaerobic bacteria associated with BV
- Gardnerella vaginalis (most common)
- Mycoplasma hominis
- Prevotella species
Risk factors for BV?
- 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/multiple sexual partners
- Afro-Caribbean ethnicity
- Excessive vaginal douching: introduction of cleaning solutions into the vagina
- Bubble baths, shower gels and “feminine hygiene” products
- Copper coil (not known if the IUS such as the “Mirena” has the same effect)
- Smoking
- Recent antibiotics
When taking a history from someone with typical symptoms of bacterial vaginosis, the diagnosis can be quite obvious based on the fishy-smelling discharge.
What else should you assess for?
Assess for causes and give advice.
Example - sensitively ask about the use of soaps to clean the vagina and vaginal douching and provide information about how these can increase the risk.
Clinical presentation of BV?
Half of women with BV are asymptomatic.
- Fishy-smelling watery grey or white vaginal discharge (standard presenting feature)
- A cyclical appearance of symptoms which worsen after sexual intercourse, cunnilingus or menstruation
- Larger volumes of vaginal discharge, occasionally requiring a panty liner to control
- Discharge takes on a thin consistency compared to physiological discharge
Are itching, irritation and pain typically associated with BV?
No - suggest an alternative cause or co-occurring infection.
What investigation should be conducted for patients with suspected BV?
A thorough female pelvic examination
Speculum + high vaginal swab (to exclude other causes of symptoms)
N.B. Examination is not always required where the symptoms are typical, and the women is low risk of sexually transmitted infections.
What clinical findings may there be on a thorough female pelvic examination in BV?
- A thin white discharge coating the vaginal walls or the speculum
- Offensive smell to discharge
- An alkali pH if a litmus test is used
Patients are unlikely to be tender on bimanual examination.
What are some potential protective factors for BV?
- Using barrier methods during sexual activity, such as condoms and dams
- Washing genitals externally with water alone
- The combined oral contraceptive pill
How can vaginal pH be tested?
Vaginal pH can be tested using a swab and pH paper.
What is a normal vaginal pH?
3.5-4.5
What vaginal pH does BV occur at?
> 4.5
Potential differentials for BV?
- Candida (thrush)
- STIs: chlamydia, gonorrhoea, herpes simplex virus (HSV), trichomoniasis vaginalis (TV)
- Physiological discharge
- Pregnancy
- Atrophic vaginitis
- Chemical irritants: lead to allergic vaginitis
- 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
- Tumour (vulva, vagina, cervix or endometrium): this can be benign or malignant and will require an urgent gynae-oncology review
What is the most likely cause of discharge changes in post-menopausal women?
Atrophic vaginitis
What causes discharge changes in atrophic vaginitis?
A reduction in oestrogen leading to localised irritation
When considering chemical irritants as a differential to BV, what should you ask about?
- Changes in body wash
- Laundry detergents
- Lubricants
- Use of sex toys
What foreign body is most likely to cause changes to discharge?
Tampons
Describe discharge & odour in
a) BV
b) Candida
c) Trichomonias vaginalis
d) Physiological
a) thin, white-grey, fishy
b) thick, white, non-offensive
c) thin, frothy, fishy
d) changes through menstrual cycle, often clear or white, odourless
Describe vulval irritation in
a) BV
b) Candida
c) Trichomonias vaginalis
d) Physiological
a) usually none but occasional burning and itching
b) vulvovaginitis causing itching, fissures and swelling
c) Itching, soreness and dysuria
d) nil
Describe vaginal pH in
a) BV
b) Candida
c) Trichomonias vaginalis
d) Physiological
a) >4.5
b) <4.5
c) >5
d) <4.5
Investigations in BV?
- A standard charcoal vaginal swab can be taken for microscopy as well as STI screening (can be a high vaginal swab taken during a speculum examination or a self-taken low vaginal swab)
- Vaginal pH can be tested using a swab and pH paper
What is seen on microscopy in BV?
Bacterial vaginosis gives “clue cells” on microscopy.
What are ‘clue cells’?
Clue cells are epithelial cells from the cervix that have bacteria stuck inside them, usually Gardnerella vaginalis.
A diagnosis of BV can be made based on bedside investigations using what 2 criteria?
1) Amsel criteria
2) Hay/Ison criteria
What are the Amsel criteria?
How many must be met to make a diagnosis of BV?
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 fluid
What do the Hay/Ison criteria take into account?
The Hay/Ison criteria take into account the microscopic appearance of gram-stained vaginal smear.
The appearance of vaginal flora is graded in the Hay/Ison Criteria.
What are the gradings?
Grade 1 (normal): lactobacillus morphotypes predominate
Grade 2 (intermediate): mixed flora with some Lactobacilli present, but Gardnerella or Mobiluncus morphotypes also present
Grade 3 (BV): predominantly Gardnerella and/or Mobiluncus morphotypes. Few or absent lactobacilli
Grade 4: gram-positive bacteria predominate
Management of asymptomatic BV?
Asymptomatic BV does not usually require treatment. Additionally, it may resolve without treatment.
What is the Abx of choice in treating BV?
Metronidazole
Usually oral metronidazole 400-500 mg BD for 5-7 days
Why is metronidazole the Abx of choice in BV?
Metronidazole specifically targets anaerobic bacteria.
What is an alternative (but less optimal) Abx than Metronidazole in BV?
Clindamycin
How is metronidazole in the treatment of BV managed?
This is given orally, or by vaginal gel.
Oral metronidazole 400-500 mg BD for 5-7 days