Porth's Essentials of Pathophysiology, 4e

1056

Genitourinary and Reproductive Function

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Vaginal-Urogenital-Systemic Infections Some STIs infect male and female genital and extra- genital structures. Among the infections of this type are chlamydial infections, gonorrhea, and syphilis. Many of these infections also pose a risk to infants born to infected mothers. Some infections, such as syphilis, may be spread to the unborn infant while in utero, whereas others, such as chlamydial and gonorrheal infections, can be spread to the infant during the birth process. Chlamydial Infections Chlamydial infection is the most frequently reported bacterial STI in the United States, with an incidence esti- mated to bemore than twice that of gonorrhea. According the Centers for Disease Control and Prevention (CDC), an estimated 2.86 million infections occur annually. 25 A large number of cases go unreported because most people with chlamydia are asymptomatic and do not seek test- ing. If untreated, chlamydial infections can lead to seri- ous complications including pelvic inflammatory disease, infertility, ectopic pregnancy, and chronic pelvic pain. 25 Etiology and Pathogenesis Chlamydia trachomatis is an obligate intracellular bac- terial pathogen that is closely related to gram-negative bacteria. 9,10 It resembles a virus in that it requires tis- sue culture for isolation, but like bacteria, it has both DNA and RNA and is susceptible to some antimicro- bial agents. Chlamydial infection exists in two morpho- logically distinct forms during its unique life—a small infectious elementary body and a large noninfectious reticulate body. Much like a spore, the elementary body ■■ Bacterial vaginosis is a polymicrobial disorder characterized by a lack of hydrogen peroxide– producing lactobacilli and an overgrowth of anaerobic organisms, including G. vaginalis, Mobiluncus species, and M. hominis. It is the most prevalent vaginal disorder in women of reproductive age.The predominant symptom of bacterial vaginosis is a thin, grayish-white discharge that has a foul, fishy odor. ■■ The manifestations of infection with Trichomoniasis vaginalis, the causative agent of trichomoniasis, are primarily observed in women, and range from asymptomatic presentation to a copious, frothy, malodorous green or yellow discharge.The disorder is associated with pelvic inflammatory disease, endometritis, infertility, and premature labor. It has also been shown to facilitate human immunodeficiency virus (HIV) infection.

and postcesarean endometritis, have been shown to be associated with asymptomatic bacterial vaginosis. It has also been associated with increased risk of acquisition of HIV and HSV infection. The diagnosis of bacterial vaginosis is made when at least three of the following signs or symptoms are present: abnormal gray discharge, vaginal pH above 4.5 (usually 5.0 to 6.0), positive fishy odor of vaginal dis- charge on addition of 10% potassium hydroxide, and appearance of characteristic “clue cells” on wet-mount microscopic studies. 4 Because G. vaginalis can be a part of the normal vaginal flora, cultures should not be done routinely. Bacterial vaginosis may be treated with oral or topi- cal metronidazole or clindamycin and oral tinidazole. Symptomatic pregnant women can also be treated with metronidazole or clindamycin. 2,4 Some studies have shown that screening for and treating bacterial vagi- nosis may reduce the incidence of adverse pregnancy outcomes. However, studies do not confirm a benefit from universal testing of low- and medium-risk preg- nant women. FIGURE 41-4. Clue cells. Clue cells are epithelial cells with clumps of bacteria clustered on their surface. Clue cells indicate the presence of bacterial vaginosis. (From the Centers for Disease Control and Prevention Public Health Image Library. No. 3720. Courtesy of M. Rein.)

SUMMARY CONCEPTS

■■ Candidiasis, trichomoniasis, and bacterial vaginosis are common vaginal infections that become symptomatic because of changes in the vaginal ecosystem. ■■ Candidiasis, also called a yeast infection, is a frequent cause of vulvovaginitis. Candida can be present without producing symptoms; usually some host factor, such as altered immune status, contributes to the development of vulvovaginitis.