Bacterial Vaginosis (BV): Vulvovaginal Candidiasis, Trichomonas Vulvovaginitis

BACTERIAL VAGINOSIS (BV)

Bacterial vaginosis (BV) is a polymicrobial infection char-acterized by a lack of hydrogen peroxide-producing lacto-bacilli and an overgrowth of facultative anaerobic organisms including G. vaginalis, Mycoplasma hominis, Bacteroides species, Peptostreptococcus species, Fusobacterium species, Prevotella species, and Atopobium vaginae.

Women with BV generally complain of a “musty” or “fishy” odor with an increased thin gray-white to yellow discharge. The discharge may cause mild vulvar irritation in approximately 25% of the cases. The vaginal discharge is mildly adherent to the vaginal wall and has a pH greater than 4.5.

Microscopic examination made under saline wet mount shows a slight increase in white blood cells, clumps of bacteria, loss of normal lactobacilli, and characteristic “clue cells” (Fig. 26.1). These are epithelial cells with nu-merous coccoid bacteria attached to their surface, which makes their borders appear indistinct and their cytoplasm resemble “ground glass.” Because the bacteria that cause BV are part of the normal vaginal flora, the mere presence of these organisms is not diagnostic. The diagnosis of BV is defined by any three of the following four criteria: (1) ab-normal gray discharge, (2) pH greater than 4.5, (3) positive “whiff test,” and (4) the presence of clue cells.

BV may be treated with oral or topical metronidazole or oral or topical clindamycin. Symptomatic pregnant women can also be treated with these medications, as neither drug has been shown to have teratogenic effects. Some studies have shown that screening for and treatment of BV in women with high-risk pregnancies may reduce the incidence of premature rupture of membranes (PROM) and preterm delivery. However, studies do not confirm that universal BV screening and treatment in asympto-matic pregnant women helps prevent adverse outcomes. In nonpregnant women, BV has been associated with other in-fections, including pelvic inflammatory and postoperative infections. It has also been associated with an increased risk of acquisition of human immunodeficiency virus (HIV) and herpes simplex virus (HSV). Although preoperative BV treatment may help prevent complications stemming from postoperative infection, treatment for BV has not been shown to decrease the risk of the HIV or HSV infection.

Vulvovaginal Candidiasis

Vulvovaginal candidiasis is caused by ubiquitous airbornefungi. Approximately 90% of these infections are caused by Candida albicans (Fig. 26.2). The remaining cases are causedby Candida glabrata, Candida tropicalis, or Torulopsis glabrata. Candida infections generally do not coexist with other infections and are not considered to be sexually transmit-ted, although 10% of male partners have concomitant pe-nile infections. Candidiasis is more likely to occur in women who are pregnant, diabetic, obese, immunosuppressed, on oral contraceptives or corticosteroids, or have had broad-spectrum antibiotic therapy. Practices that keep the vaginal area warm and moist, such as wearing tight clothing or the habitual use of panty liners, may also increase the risk of Candida infections.

The most common presenting complaint for women with candidiasis is itching, although up to 20% of women may be asymptomatic. Burning, external dysuria, and dys-pareunia are also common. The vulva and vaginal tissues are often bright red in color, and excoriation is not un-common in severe cases. A thick, adherent “cottage cheese” discharge with a pH of 4 to 5 is generally found. This dis-charge is odorless.

Multiple studies conclude that a reliable diagnosis can-not be made on the basis of history and physical examina-tion alone. Over-the-counter (OTC) treatments are safe and effective, but any woman who does not respond to OTC treatment or who has a recurrence soon after treat-ment should be seen by a physician for a definitive diagno-sis. Patients who have self-administered treatment with OTC medications should be advised to stop treatment three days before their office visit. Diagnosis requires either visualization of blastospores or pseudohyphae on saline, or 10% KOH microscopy, or a positive culture in a sympto-matic woman. The diagnosis can be further classified as uncomplicated or complicated vulvovaginal candidiasis (Box 26.1). Latex agglutination tests may be of particular use for non-Candida albicans strains, because they do not demonstrate the pseudohyphae on wet prep.

Treatment of candida infections is primarily with the topical application of one of the synthetic imidazoles, such as miconazole, clotrimazole, butoconazole, or tercona-zole in cream or suppository form placed intravaginally. Short-term oral therapy with low-dose (150 mg) flucona-zole has become widely used. Pregnant women should be treated with topical agents due to the increased risk of birth defects associated with high doses (400 to 800 mg) of fluconazole.

Box 26.1

Classification of Vulvovaginal Candidiasis

Although these agents are associated with high cure rates, approximately 20% to 30% of patients experience re-currences one month after treatment. Weekly therapy with fluconazole for six months has been shown to be effective in preventing recurrent candidiasis in 50% of women. Intermittent therapy with topical agents (weekly or twice weekly) can also be used for prevention. T. glabrata is resis-tant to all azoles and may respond to therapy with intra-vaginal boric acid capsules or gentian violet. Patients with frequent recurrences should be carefully evaluated for pos-sible risk factors such as diabetes or autoimmune disease. Prophylactic local therapy with an antifungal agent should be considered when systemic antibiotics are prescribed.

Trichomonas Vulvovaginitis

T. vaginalis is a flagellate protozoan that lives only in thevagina, Skene ducts, and male or female urethra. The infec-tion can be transmitted by sexual contact, but can also occur via fomites, and the organism has been known to survive in swimming pools and hot tubs. Trichomoniasis is associated with pelvic inflammatory disease (PID), endometritis, in-fertility, ectopic pregnancy, and preterm birth, and it often coexists with other sexually transmitted diseases and BV. It has also been shown to facilitate HIV transmission.

Symptoms of trichomonas infection vary from mild to severe and may include vulvar itching or burning, copious discharge with rancid odor, dysuria, and dyspareunia. Although not present in all women, the discharge associ-ated with trichomonas infections is generally “frothy,” thin, and yellow-green to gray in color, with a pH above 4.5. Examination may reveal edema or erythema of the vulva. Petechiae, or strawberry patches, are classically de-scribed as present in the upper vagina or on the cervix, but are actually found in only about 10% of affected patients. A significant number of women with trichomoniasis are asymptomatic.

The diagnosis is confirmed by microscopic examina-tion of vaginal secretions suspended in normal saline. This wet smear will show large numbers of mature epithelial cells, white blood cells (WBCs), and the trichomonas or-ganism (Fig. 26.3). A point-of-care test for trichomonas antigens, the OSOM Trichomonas Rapid Test, has a sen-sitivity of 88.3% and specificity of 98.8% compared with culture. Women diagnosed with trichomoniasis should also undergo screening for other STDs, especially gonor-rhea and chlamydia.

Treatment of trichomonas infections is with oral metronidazole or tinidazole. Treating sexual partners of women with trichomoniasis is recommended, and individ-uals undergoing treatment should avoid unprotected intercourse. Abstinence from alcohol use when taking metronidazole is necessary to avoid a possible disulfiram-like reaction. Trichomoniasis has been associated with preterm delivery, PROM, and low birth weight. Pregnant patients should be treated, and metronidazole is consid-ered safe for use during pregnancy. However, treatment may not prevent these pregnancy complications.

Although follow-up examination of patients with tri-chomoniasis for test of cure is often advocated, they are usu-ally not cost-effective, except in the rare patient with a history of frequent recurrences. In these patients, reinfec-tion or poor compliance must be considered as well as the possibility of infection with more than one agent or other underlying disease. Infections with metronidazole-resistant T. vaginalis have been reported. Although absolute resistance is rare, relative resistance may be as high as 5%. These infections are treated with high doses of tinidazole.