Trichomoniasis: Causes and Treatment - Essay Example

Trichomoniasis Introduction: Genitourinary tract infections are among the most frequent disorders for which patients seek care from gynecologists. By understanding the pathophysiology of these diseases and having an effective approach to their diagnosis, physicians can institute appropriate antimicrobial therapy to treat these conditions and reduce long-term sequelae. It is not known what triggers the disturbance of normal vaginal flora. It has been postulated that repeated alkalinization of the vagina, which occurs with frequent sexual intercourse or use of douches, plays a role (World Health Organization, 2004). Trichomoniasis: Trichomoniasis is the second most common sexually transmitted infection. This sexually transmitted disease is not reportable, so the epidemiologic data remains very difficult to obtain. However, it has been estimated that there are 5 million new cases in the United States each year, which is more than the sum of all cases of Chlamydia and gonococcal infections. The World Health Organization estimates that there is incidence of 173 million new infections of Trichomoniasis worldwide per year. This is also known as Trichomonas vaginitis. It is caused by the sexually transmitted, flagellated parasite, Trichomonas vaginalis. The transmission rate is high; 70% of men contract the disease after a single exposure to an infected woman, which suggests that the rate of male-to-female transmission is even higher. The parasite, which exists only in trophozoite form, is an anaerobe that has the ability to generate hydrogen to combine with oxygen to create an anaerobic environment. It often accompanies bacterial vaginosis, which can be diagnosed in as many as 60% of patients with Trichomonas vaginitis (Cates, Jr., 1999, S2-S7). Risk Factors: There are certain risk factors that are associated with Trichomoniasis. These include all the risk factors for sexually transmitted infection acquisition. These are multiple or new partners, non-use of barrier method of contraception, young age, minority member, lower socioeconomic status, and other sexually transmitted diseases. Chlamydial infection is a particularly high risk factor; up to 30% of women with Chlamydial cervicitis also have Trichomoniasis. Peak years of prevalence for Trichomoniasis occur later in life-among 20- to 46-year-olds. There is generally a longer duration of infectiousness and a high level of asymptomatic infections, especially in men. Many women with annual Pap smear examination have asymptomatic infections. This is responsible for 25% of all cases of clinically diagnosed vaginitis. More than half of infected women and nearly 90% of infected men are asymptomatic, which increases the reservoir of people spreading the infection. Trichomoniasis increases the risks of human immunodeficiency virus (HIV) transmission and HIV acquisition (Horowitz, Mrdh, eds., 1999). Infection: The primary mode of transmission of T. vaginalis is through sexual contact. Transmission by fomites is possible, but is rarely the cause of a symptomatic infection. An inoculums of at least 10,000 organisms is needed to establish a clinically significant infection. Male-to-female transmission rates are higher than female-to-male rates; about 85% of exposed women will contract the infection. Female-to-male transmission rates are more variable, but may be as high as 70% within 48 hours of exposure. Incubation period varied between 4 to 28 days. T. vaginalis resembles anaerobic bacteria more than eukaryotic behavior in that it ferments large amounts of carbohydrates into carbon dioxide and hydrogen gases, causing bubbles. Its presence in the vaginal vault changes the vaginal microbiology-the lactobacilli disappear and anaerobic bacteria predominant. T. vaginalis swims freely in the vaginal discharge but can also attach to the vaginal wall. The cell membranes of the parasite and those of the host interdigitate. Trichomonas adhere to vaginal and cervical epithelial cells. T. vaginalis also infects the urethra, Skene's glands, and Bartholin glands. The organism does not invade into the underlying tissues but precipitates an intense inflammatory response locally (Sweet and Gibbs, 2002, 339-40). Clinical Features: Half of women infected with T. vaginalis are asymptomatic, but about 30% of these women will develop symptoms when they are followed for 6 months. Local immune factors and inoculum size influence the appearance of symptoms. Symptoms and signs may be much milder in patients with small inocula of Trichomonas, and Trichomonas vaginitis often is asymptomatic. In symptomatic Trichomoniasis, there is profuse, purulent, malodorous vaginal discharge with frothy appearance that may be accompanied by vulvar pruritus or edema. The odor may not be because of the original Trichomonas infection, but may result from concomitant bacterial vaginosis. Vaginal secretions may exude from the vagina. In patients with high concentrations of organisms, a patchy vaginal erythema and colpitis macularis may be observed. Women may also have complaints of urinary frequency, dysuria, dyspareunia, and/or postcoital spotting. Dysuria and frequency may be caused by a urethral infection; dyspareunia and postcoital spotting generally result from the inflamed and friable cervix. The pH of the vaginal secretions is usually higher than 5.0. Microscopy of the secretions reveals motile Trichomonas and increased numbers of leukocytes. Clue cells may be present because of the common association with bacterial vaginitis. The whiff test may be positive (Wolner-Hanssen, Krieger, Stevens et al., 1989, 571-576). Physical Examination: On physical examination, an infected woman may have copious amounts of frothy discharge at her introitus with erythema and some edema in the vestibule and surrounding labia. The vaginal vault may be coated with gray or yellow-green-colored frothy discharge, which often pools in the upper vault. The bubbles in the discharge, which are characteristic of this infection, result from the metabolism of carbohydrates into carbon dioxide and hydrogen gases. Wiping away the discharge from the cervix, the portio may seem to have an injected, edematous appearance speckled with clusters of petechiae or punctate mucosal hemorrhages, which has classically been described as a "strawberry" or "flea-bitten" cervix. These petechiae are best seen with colposcopic magnification. The cervix may be quite friable, but in the absence of other sexually transmitted infections, there should not be cervical motion tenderness (Wolner-Hanssen, Krieger, Stevens et al., 1989, 571-576). Laboratory Diagnosis: T. vaginalis can be isolated in urine, semen, and vaginal discharge. The standard diagnostic test is microscopic examination of vaginal discharge. Collecting and handling of the specimen are critically important in improving the sensitivity of the wet-mount test. The classic technique of placing a drop of the vaginal secretions directly onto a slide and mixing in some normal saline, then trapping the specimen under a cover slide is most effective when the specimen is promptly examined (Sweet and Gibbs, 2002, 339-40). Morbidity: Morbidity associated with Trichomoniasis may be related to bacterial vaginitis. Patients with Trichomonas vaginitis are at increased risk for postoperative cuff cellulitis following hysterectomy. Pregnant women with Trichomonas vaginitis are at increased risk for premature rupture of the membranes and preterm delivery. Because of the sexually transmitted nature of Trichomonas vaginitis, women with this infection should be tested for other sexually transmitted diseases, particularly Neisseria gonorrhoeae and Chlamydia trachomatis. Serologic testing for syphilis and human immunodeficiency virus (HIV) infection should also be considered (Horowitz, Mrdh, eds., 1999). Treatment: Metronidazole is the drug of choice for treatment of vaginal Trichomoniasis. Both a single 2 g oral dose and a multidose, 500 mg twice daily for 7 days' regimen are highly effective and have cure rates of about 95%. The sexual partner should also be treated. Women who do not respond to initial therapy should be treated again with metronidazole, 500 mg, twice daily for 7 days. Patients who do not respond to repeated treatment with metronidazole or tinidazole and for whom the possibility of reinfection has been excluded should be referred for expert consultation (Horowitz, Mrdh, eds., 1999). Reference List Cates W Jr., 1999. Estimates of the incidence and prevalence of sexually transmitted diseases inthe United States. American Social Health Association Panel. Sex Transm Dis 1999; 26:S2-S7. Horowitz BJ, Mrdh P-A, eds., 1999, Vaginitis and Vaginosis. New York, NY: Wiley-Liss Soper D., 2004. Trichomoniasis: under control or undercontrolled Am J Obstet Gynecol;190:281-290 Sweet RL, Gibbs RS., 2002. Infectious Diseases of the Female Genital Tract, 4th Ed.Philadelphia, PA: Lippincott Williams & Wilkins, 2002, pp. 339-340. Wolner-Hanssen P, Krieger JN, Stevens CE, et al., 1989, Clinical manifestations of vaginaltrichomoniasis. JAMA;261:571-576. World Health Organization, 2004. Sexually Transmitted Infections Fact Sheet. Geneva,Switzerland: World Health Organization. Available from: www.who.int/reproductive-health/rtis/docs/sti_factsheet_2004.pdf. Accessed November 26, 2008. Read More