Bacterial Vaginosis Michael Addidle What is Bacterial Vaginosis (BV) ? • Polymicrobial vaginal infection involving a reduction in the amount of Lactobacilli bacteria and an overgrowth of anaerobic bacteria. Some key facts • Condition first described by Gardner and Dukes in 1955. • Initially thought to be due to which organism? • Most common infective cause of vaginal discharge in women of childbearing age. • Prevalence is approximately 20-30% • Approximately 50% symptomatic • The absence of inflammation is the basis of the term vaginosis as opposed to vaginitis Risk Factors for BV • • • • Multiple or new sexual partners Oro-genital sex Smoking Genetic predisposition Normal vaginal flora ? What else is normal vaginal flora? What part does age play in the make-up of normal vaginal flora? Pathogenesis • Normal vaginal flora in women of reproductive age is predominately lactobacilli. (Bit unusual) • At puberty eostrogen levels increase, stimulates glycogen uptake by vaginal epithelial cells. Glycogen one of main food sources of lactobacilli. • Lactobacilli produce both lactic acid and hydrogen peroxide. • Vaginal epithelial cells also produce lactic acid as a byproduct of glycogenolysis. • This makes the vaginal pH acidic • The hydrogen peroxide is also toxic against other bacterial species. • Lactobacilli per se are very low virulence bacteria. (Probiotic yoghurts etc), therefore its predominance is thought to have a protective effect against vaginal/pelvic infections. • At menopause, eostrogen levels decrease so lactobacilli often become non-dominant. Makes BV more difficult to diagnose Names to remember in BV • Amsel • Nugent • Hay Presentation of BV Amsel’s Criteria (introduced 1984) (3 out of 4 criteria below required to establish the diagnosis) • Vaginal discharge, thin white/grey • Fish like odour. (accentuated by addition of Potassium Hydroxide KOH) • Vaginal PH >4.5 (Litmus paper is a bedside test) • Presence of clue cells on laboratory examination. What are the problems with Amsel’s criteria? Introduced 1991 Hay’s Criteria (2002) Problems with Hay’s criteria? Other methods • DNA probes • DNA probes + pH Bacterial Vaginosis: Quality Assurance of results • Condition of degrees • Clear cut at either end of the spectrum. • Those in the middle (including AVF) are less clear cut. • Degree of subjectivity • External QC/Internal QC? The consequences of Bacterial Vaginosis • Causal relationship between BV and endometrial bacterial colonisation, endometritis, premature labour, postpartum fever, post-hysterectomy vaginal cuff cellulitis and post-abortal infection. • BV is a risk factor for HIV transmission (&other STDs). May be due to the lack of hydrogen peroxide producing lactobacilli in the vaginal flora of women with BV Bacterial vaginosis : Treatment • Metronidazole 400mg orally bd for 7 days. • Clindamycin 300mg orally bd for 7 days. • Metronidazole and Clindamycin gels can also be used. • Avoid gels during pregnancy. No evidence that they reduce the risks to the baby. • No evidence to suggest that woman’s response to therapy and risk of relapse are influenced by treatment of her male sex partner. Screening and treatment of asymptomatic infection • Generally asymptomatic infection not treated as patients often spontaneously improve and therapy often complicated by symptomatic vaginal yeast infection. • Treatment indicated for asymptomatic women who are about to undergo gynae procedures(in particular termination of pregnancy) and in “high risk pregnancies.” • No evidence that treating sexual partners of women with BV is beneficial. Bacterial Vaginosis (BV) in pregnancy (15-30%) • Why is BV a particular problem in pregnancy – More common than in non-pregnant pop. – Associated with premature labour & delivery – Controversial association with miscarriage – Post-partum endometriosis However treatment of BV may not return these risks to baseline levels. Benefit greatest in those higher risk pregnancies. When to look for and treat BV in pregnancy • Asymptomatic High Risk Pregnant women (previous pre-term delivery). Can consider screening these women for BV even if asymptomatic. • There is no evidence for routine screening for BV in pregnancy in all expectant mothers. Bacterial Vaginosis:Relapse • 30% recurrence in 3 months • 50% recurrence in 12 months • Long term suppressive antibiotics may be indicated when three or more episodes within a 12 month period.