Genital tract disorders

13 Genital tract disorders





Vulvovaginal Conditions



Vaginitis: thrush






When is it most likely to occur?


Vaginal infections occur when there are changes to the ‘ecological’ environment that favour one or more types of organism over the status quo.


Despite the fact that thrush is probably one of the most common conditions affecting women, its aetiology and epidemiology remain poorly understood. The development of thrush has been linked to several factors including the recent use of antibiotics and oral contraceptives, the presence of diabetes mellitus, dietary practices, gastrointestinal colonisation by the organism, clothing and sanitary protection practices, sexual communicability of



the organism and specific immunological defects. However, the data supporting each of these factors are conflicting, and to date none is predictive of infection. The evidence related to each of these risk factors is summarised in Table 13.1.


TABLE 13.1 Epidemiological associations with vulvovaginal candidiasis (VVC)



























Risk factor Summary of the evidence
Antibiotics

Sexual factors




Oral contraceptive use

Other methods of contraception There is a higher risk with:


Sanitary pads and tampons Studies have failed to establish a link between thrush and either douching, tampons or sanitary pads.122,123
Tight-fitting clothing Is anecdotal and unproven.6
Dietary factors Are anecdotal and unproven; one RCT is too small to draw any conclusions.124







There are many different products available to manage acute thrush: which are the best to use?


Women and their doctors are often confused by the wide variety of products and formulations available for the treatment of candidiasis. Importantly, none of the available drugs are fungicidal. While they can reduce Candida to below detectable levels, they are not necessarily able to eradicate the organism completely. Azoles such as clotrimazole, econazole or miconazole (topical and oral) give an 80–95% clinical and mycological cure rate in acute thrush in non-pregnant women. By comparison, nystatin, an older product, gives a 70–90% cure rate under these circumstances.4


Differences in formulation are not thought to affect treatment outcome, and are more a function of patient preference.5


Women have the option of either topical or oral therapy. Creams are effective and give quicker initial relief than oral agents. Oral azoles, such as fluconazole or itraconazole as a 1-day course, are equally as effective as topicals (but a more expensive option), but they may have a delay in onset of action of 12–24 hours. They may also result in systemic side effects in 10% of users. These effects include gastrointestinal intolerance, headache and rashes, but are usually mild and transient.6 Oral ketoconazole is indicated only in cases not responsive to other agents. It should not be used for superficial fungal infections because of the potential risk of liver toxicity.



It is important to be aware of the fact that antifungal vaginal agents can produce local side effects characterised by burning, itching, soreness, erythema and oedema, especially with repeated application. For this reason, if the vulva is very inflamed oral treatment may be preferred. Another reason for using oral therapy is if the woman doesn’t feel comfortable using pessaries or products requiring the use of intravaginal applicators.


Routine use of corticosteroids is not recommended. In severe infections, low-potency topical corticosteroids may rapidly reduce local inflammation and burning, but the application of higher-dose corticosteroids often exacerbates the burning sensation.6








What approach should be taken if the woman gets recurrent thrush (>4 episodes per year)?


In these women, it is essential to be sure that what you are really dealing with is thrush. For this reason, with each individual episode vaginal swabs should be taken for microscopy and culture, and topical contact dermatitis, hypersensitivity or allergic reactions excluded. The patient should also be screened for diabetes, immunodeficiency, corticosteroid use and frequent antibiotic use.4


Recurrent thrush can be a very problematic condition that can prove frustrating to treat, not only for the woman but also for the doctor. The suggested approach is to use a two-phase line of attack. An induction period reduces the Candida and alleviates symptoms. A maintenance period then follows, aimed at preventing recurrence.1


Although the optimal induction period is not currently known, recurrent infections tend to respond less well to short courses of anti-mycotics (e.g. single-dose fluconazole or 7 days of a topical). Therefore, ‘induction’ therapy is recommended with at least 1 week of oral products or 1–2 weeks of topical products.1,6


The maintenance period usually lasts for 6 months. A wide variety of different regimens have been recommended. Commonly cited ones include oral fluconazole 100 mg weekly for 6 months, or topical clotrimazole (in the form of a pessary) 500 mg weekly for 6 months.1,4,6


Unfortunately cessation of therapy results in relapse in at least 50% of women4 and a small percentage of women may require maintenance azoles for years.6


If the woman is using a combined oral contraceptive pill, some advocate switching the pill to a less oestrogenic one (see Chapter 3). In women who are not on the pill who experience recurrent thrush in the week prior to the onset of menstruation, oral fluconazole can be used on a monthly basis at this time.


Another more novel way of treating recurrent or persistent candidiasis is through the use of Depo-Provera®.11 Its mechanism of action is thought to be through its action of lowering oestradiol levels in the blood.





Vaginitis: bacterial vaginosis





What causes BV?


The literature has yet to show a real understanding of why BV occurs or how its recurrence can be stopped. The prevalence of BV varies with ethnicity (with rates of >33% in studies of Indigenous Australian women,17 and >50% in sub-Saharan African and African American women18), low socioeconomic status, a history of STDs, large numbers of sexual partners and a recent change in sexual partner. A high concordance of BV between women in lesbian relationships has also been reported.19



What is the significance of BV?


BV puts women at greater risk of developing other STIs, especially HIV.20 It can also lead to infective complications after surgery and premature birth (see p 233).




How is the diagnosis of BV made?


Examination of a woman with a complaint of a vaginal discharge or odour should include an evaluation for the clinical criteria (Amsel criteria)23 of BV (Box 13.2). At least three of these criteria must be present for a diagnosis of BV to be made.



The odour of the vaginal secretions can be tested by smelling the withdrawn speculum (the ‘whiff test’); normal vaginal secretions do not have an unpleasant odour. If this test is negative, a more sensitive procedure for detecting the amines produced is performed by adding a few drops of 10% potassium hydroxide (KOH) to a few drops of vaginal secretions. The mixture should be smelt (‘whiffed’) immediately for the transient ‘dead fish’ odour characteristic of BV. KOH increases the pH to the point at which the volatilisation of polyamines, such as putrescine, cadaverine and trimethylamine, occurs. (Many women first notice vaginal malodour immediately following intercourse, because semen, which has a pH of 8.0, alkalinises vaginal fluid, thus releasing the volatile amines.)


The pH of vaginal secretions can be determined by using a strip of narrow-range pH paper (about pH 4.0–5.5), which may be applied to the withdrawn speculum or directly pressed against the vaginal wall with a swab.


Lastly, a wet mount of vaginal secretions should be tested to look for ‘clue’ cells. These are epithelial cells covered with G. vaginalis (Fig 13.6, p 232). They have a ground glass appearance and are the clues to the diagnosis of BV. By comparison, vaginal epithelial cells from women without BV have clear borders.



The Gram stain is the single, best laboratory test for diagnosis of BV. This method is preferable to culture because it has greater specificity. To prepare a vaginal smear for a Gram stain, a swab should be used to obtain vaginal fluid and cells from the vaginal wall (not the cervix). This swab should then be rolled across a slide and the material allowed to air-dry. There is no need to fix the smear prior to shipment to the laboratory: air-dried vaginal smears are stable at room temperature for months.




How is BV treated?


There are two options, either oral or topical treatment. First-line treatment of BV is either oral metronidazole (Flagyl) or tinidazole (Fasigyn) or the use of the vaginal cream clindamycin. These treatments are outlined in Box 13.3. Oral and topical therapy have the same efficacy, with cure rates of 70–90%.30 There is no evidence of teratogenicity of metronidazole in women during the first trimester of pregnancy.3133 Regardless of which therapy is used, BV will recur in over half of the women in which treatment seemed effective.34 In this group it may be helpful to suggest condom use because of the associated decreased incidence of BV among female partners35 (perhaps because the pH of semen does not affect the vaginal ecosystem when condoms are used).






What is the association between BV and premature birth?


There are many and varied reasons why premature birth occurs. In up to 40% of cases, the cause is infection,45 with one of the strongest correlations with premature delivery being the existence of chorioamnionitis. This condition is also associated with failure of the tocolytic drug therapy that is used to delay or reverse the onset of labour. Examination of the amniotic fluid or chorioamniotic membranes of women who experience premature labour and premature rupture of membranes commonly finds evidence of infection manifested by the presence of organisms and inflammatory cytokines. Most of these microorganisms are thought to come from the vagina, particularly from women with BV.46


In typical obstetric populations, BV is prevalent in 10–30% of women.47 In a study of high-risk pregnant women, the prevalence was 50%.48 Studies looking at the association between BV in pregnancy and premature delivery have found relative risks ranging from 0 to 6.9. A recently published meta-analysis reviewed 19 studies looking at the association and found a 60% increased risk of premature delivery given the presence of BV, or an odds ratio of 1.6.49


This association has enormous clinical significance, but the association between BV and premature delivery is not clear-cut. It is thought that BV is only a marker for something else—presumably subclinical infection of the upper genital tract that then leads to premature delivery. Interestingly, spontaneous regression of BV during pregnancy as assessed by vaginal Gram stain does not appear to improve perinatal outcomes.50



Does treatment of BV decrease the risk of premature birth?


A Cochrane review51 has found that antibiotic therapy was highly effective in eradicating infection during pregnancy. They also found that, while treating BV during pregnancy resulted in a trend towards fewer births before 37 weeks’ gestation, it only significantly prevented births before 37 weeks’ gestation in the subgroup of women with a previous premature birth (odds ratio 0.37, 95% CI 0.23–0.60).


This means that the current evidence does not support screening and treating all pregnant women for BV to prevent premature birth and its consequences. However, a proportion of those women with a history of premature birth may benefit from detection and treatment, preventing a further premature birth.





Vaginitis: trichomoniasis






How can a diagnosis be made?


Classically vaginal discharge is frothy, yellowy-green in colour and malodorous (Figs 13.7 and 13.8, p 234). The vulva and vagina appear inflamed (in contrast to BV) and a ‘strawberry cervix’ (this appearance is due to punctuate haemorrhages) is visible to the naked eye in 2% of patients.






The clinical features are not sufficiently sensitive to diagnose Trichomonas vaginalis infection.53 Diagnosis should therefore occur either through microscopy or culture of the organism. A swab is taken from the pool of discharge in the posterior fornix of the vagina. If a microscope is to hand, the Trichomonas can be seen as a unicellular flagellated protozoan in a saline wet mount. Culture requires a special medium. Sometimes Trichomonas infection is detected on a Pap smear as an incidental finding. Cervical cytology has a sensitivity of only 60–80% for Trichomonas, however, and a false positive rate of 30%, so its use as a diagnostic test is not recommended.54



What treatment is there?


Trichomonas is effectively treated with metronidazole. It can be taken either as a stat dose of 2 g or a twice-daily dose of 400 mg for 7 days. While compliance and expense favour the stat dose, the failure rate (5%) may be higher with single-dose therapy, possibly because of failure to treat partners concurrently. Side effects of metronidazole include nausea, a metallic taste and the need to abstain from using alcohol during use and for 48 hours afterwards.


Contrasting with BV, vaginal preparations such as metronidazole gel are not effective at treating Trichomonas (50%). Topically applied antimicrobials are unlikely to achieve therapeutic levels in the urethra or perivaginal glands and are therefore not recommended for use.


Some strains of T. vaginalis have diminished susceptibility to metronidazole. Thankfully, most of these will respond to higher doses of metronidazole. If treatment fails with either regimen, the patient should be re-treated with metronidazole 500 mg twice a day for 7 days. If treatment fails again, the patient should be treated with a single, 2 g dose of metronidazole once a day for 3–5 days.55


As with all STIs, sexual partners need to be treated simultaneously, contacts traced and screening for concurrent STIs undertaken.


Patients should be instructed to avoid sex until they and their sex partners are cured, i.e. when therapy has been completed and patient and partner(s) are asymptomatic (in the absence of a microbiologic test of cure).





Herpes




What causes herpes?


The herpes simplex virus (HSV) belongs to the Herpetoviridae family, the properties of which are described in Box 13.4. It gains access to sensory neurones through abraded skin, causes latency and persists for the life of the host. There are two types of HSV, type 1 and 2. Both types can cause oral and/or genital herpes, although type 1 favours oral sites and type 2 genital infections.




How common is it?


The prevalence and epidemiology of the two types of HSV are quite different. HSV1, traditionally associated with oral infection, is prevalent in about 20% of children <5 years of age and the prevalence rises in a linear fashion thereafter.58 Eventually about 80% of people acquire HSV1.59 Interestingly only a third report ever having a ‘cold sore’.60 HSV1 genital herpes may be increasing in incidence, especially in younger people. In a Melbourne study, the proportion of first-episode genital herpes due to HSV1 increased from 15.8 to 34.9% of cases between 1980 and 2003.61 The rising incidence of HSV1 genital herpes could be the result of decreasing HSV1 seroprevalence and consequently a larger susceptible population and/or an increase in the popularity of oral sex.62


In contrast HSV2 is extremely rare in young people, with most disease being acquired between the ages of 15 and 40, as would be expected of an STD. Approximately 20–25% of sexually active people contract HSV2 during this time.63 Prior infection with HSV1 modifies the clinical manifestations of first infection by HSV2.64


Nov 4, 2016 | Posted by in OBSTETRICS | Comments Off on Genital tract disorders
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