Sexually transmitted diseases Flashcards
Bacterial vaginosis
Refers to an overgrowth of bacteria in the vagina, specifically anaerobic bacteria. It is not a sexually transmitted infection.
The loss of what bacteria causes Bacterial vaginosis?
Loss of the lactobacilli “friendly bacteria” in the vagina. Bacterial vaginosis can increase the risk of women developing sexually transmitted infections.
What bacteria is the main componenet of healthy vaginal bacterial flora?
Lactobacilli which produce lactic acid & 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.
How does Lactobacilli keep the vagina healthy?
Lactobacilli which produce lactic acid & 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.
Examples of anaerobic bacteria associated with bacterial vaginosis
- Gardnerella vaginalis (most common)
- Mycoplasma hominis
- Prevotella species
Risk factors for bacterial vaginosis
- Multiple sexual partners
- Excessive vaginal cleaning (douching, use of cleaning products and vaginal washes)
- Recent antibiotics
- Smoking
- Copper coil
Symptoms of bacterial vaginosis
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.
Investigations in bacterial vaginosis
A speculum examination
Vaginal pH can be tested using a swab and pH paper. BV occurs with a pH > 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.
What are clue cells?
Clue cells are epithelial cells from the cervix that have bacteria stuck inside them, usually Gardnerella vaginalis.
Specific to bacterial vaginosis
Whats the normal vaginal pH?
The normal vaginal pH is 3.5 – 4.5.
Microscopy changes in bacterial vaginosis
“Clue cells” on microscopy.
Management of bacterial vaginosis
Asymptomatic BV does not usually require treatment.
Metronidazole is the antibiotic of choice for treating bacterial vaginosis.
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,
What advice should be given to patients when prescribing Metronidazole?
Avoid alcohol for the duration of treatment.
Alcohol and metronidazole can cause a “disulfiram-like reaction”, with nausea and vomiting, flushing and sometimes severe symptoms of shock and angioedema.
Why should alcohol not be taken with metronidazole?
Alcohol and metronidazole can cause a “disulfiram-like reaction”, with nausea and vomiting, flushing and sometimes severe symptoms of shock and angioedema.
Complications of bacterial vaginosis
Increase the risk of catching STIs
Also associated with several complications in pregnant women
Complications of bacterial vaginosis in pregnant women
- Miscarriage
- Preterm delivery
- Premature rupture of membranes
- Chorioamnionitis
- Low birth weight
- Postpartum endometritis
Candidiasis
Commonly referred to as “thrush”. It refers to vaginal infection with a yeast of the Candida family. The most common is Candida albicans.
Most common organism to cause Candidasis
Candida albicans
Risk factors for candidiasis
- Increased oestrogen (higher in pregnancy, lower pre-puberty and post-menopause)
- Poorly controlled diabetes
- Immunosuppression (e.g use of corticosteriods)
- Broad-spectrum antibiotics
Presentation of candidiasis
Thick, white discharge that does not typically smell
Vulval and vaginal itching, irritation or discomfort
Investigations for candidiasis
Testing the vaginal pH using a swab and pH paper can be helpful in differentiating between bacterial vaginosis and trichomonas (pH > 4.5) and candidiasis (pH < 4.5).
A charcoal swab with microscopy can confirm the diagnosis.
Management options in candidiasis
Antifungal cream (i.e. clotrimazole) inserted into the vagina with an applicator
Antifungal pessary (i.e. clotrimazole)
Oral antifungal tablets (i.e. fluconazole)
What is Canesten Duo?
It contains a single fluconazole tablet and clotrimazole cream to use externally for vulval symptoms (e.g. in candidiasis)
They also recommend recurrent infections (more than 4 in a year) can be treated with an induction and maintenance regime over six months with oral or vaginal antifungal medications. This is an off-label use.
What advice should be given to women taking anti-fungal creams and pessaries?
Can damage latex condoms and prevent spermicides from working, so alternative contraceptive is required for at least five days after use.