Genitourinary Tract Infections
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General Goal: To know the major cause(s) of these infections, how they are transmitted, and the major manifestations of the infections.

Specific Educational Objectives: The student should be able to:

1. Identify the common cause of vaginitis discussed in this handout. Know the common or pathognomonic signs of the diseases.

2. Describe the major manifestations of each infection and differentiate it from other infections in the course.

3. Describe how you diagnose, treat and prevent these infections.

Reading: MEDICAL MICROBIOLOGY by P.R. Murray, K.S. Rosenthal, G.S. Kobayashi and M.A. Pfaller, 3rd Edition. depends on the organism.

F.S. Southwick, Infectious Diseases in 30 Days, 1st edition, McGraw Hill. p. 289-318.

Lecture: Dr. Neal R. Chamberlain

References: 

  1. Burstein GR, Zenilman JM. Nongonococcal urethritis--a new paradigm. Clin Infect Dis 1999 Jan;28 Suppl 1:S66-73
  2. Hoeprich, PD., MC. Jordan, and AR. Ronald. Infectious Diseases: A Treatise of Infectious Processes. 5th edition. 1994. J.B. Lippincott Company, Philadelphia, PA.
  3. CDC. The national plan to eliminate syphilis from the United States. Atlanta, Georgia: US Department of Health and Human Services, CDC, National Center for HIV, STD, and TB Prevention, 1999:1--84.
  4. Sexually Transmitted Disease Guidelines 2002. Recommendations and Reports
    May 10, 2002/Vol. 51/No.RR-6 (
    http://www.cdc.gov/std/treatment/TOC2002TG.htm)

Vaginitis

Vaginal infections are the most common women's health problem, and have been increasingly linked to a growing array of serious health risks. Vaginal infections, known medically as vaginitis, are the most frequent reason American women see their doctors-accounting for more than 10 million office visits each year. Some vaginal infections are transmitted through sexual contact (trichomoniasis), but others such as candidiasis (yeast infections) are not. Bacterial vaginosis is usually transmitted by sexual contact however; on rare occasions it can affect women who have never been sexually active. A recent Gallup survey found that very few women have a thorough understanding of vaginitis. While 95% of women surveyed had heard about yeast infections only 36 percent had ever heard of the MORE COMMON vaginal infection bacterial vaginosis (BV).

Etiology

Bacterial Vaginosis (BV) is caused by Gardnerella vaginalis, Mycoplasma hominis and various anaerobic bacteria including Mobiluncus sp., and Prevotella sp. BV is the most common vaginal infection. The disease has been found in 12 to 25 percent of women in routine clinic populations, 10 to 26 percent of women in obstetrics clinics and 32 to 64 percent of women in clinics for sexually transmitted infections (STI’s).

Other organisms can cause vaginitis; Candida albicans (candidiasis) and Trichomonas vaginalis (trichomoniasis). These infections of the vagina are discussed in this section of the chapter as well.

Manifestations

Vaginal infections are often accompanied by vaginitis, which is an inflammation of the vagina characterized by discharge, irritation, and itching. The cause of vaginitis cannot be adequately determined solely on the basis of symptoms or a physical examination. Laboratory tests allowing microscopic evaluation of vaginal fluid are required for a correct diagnosis. A variety of effective drugs are available for treating vaginal infections and accompanying vaginitis.

Bacterial Vaginosis

Etiology

Bacterial Vaginosis (BV) is usually caused by Gardnerella vaginalis, Mycoplasma hominis and various anaerobic bacteria including Mobiluncus sp., and Prevotella sp.

Manifestations

Bacterial vaginosis is usually manifested as an unpleasant vaginal odor in varying degrees and an excessive white or gray vaginal discharge with a milk-like consistency. Women often report that the odor is particularly embarrassing after sexual intercourse. When semen mixes with vaginal secretions, it lowers the acidity level to make the odor particularly strong. Odor may also be more noticeable around the time of menses. Vaginal itching or burning is also sometimes present. Up to 40% of women with BV may experience no outward symptoms. BV has been associated with pelvic inflammatory disease, which can result in infertility, as well as increased risk of endometritis, cervicitis, pregnancy complications, and post-operative infections. Pregnant women with BV in the 23rd to 26th weeks of pregnancy were 40% more likely to deliver a low birth-weight baby (i.e., less than 5.5 lbs).

Epidemiology

Pathogenesis

Bacterial vaginosis is caused by an overgrowth of bacteria rather than yeast or other organisms. These are primarily anaerobic bacteria and an organism called Gardnerella vaginalis, all of which can be found in low numbers in the healthy vaginal microflora. In women with BV, the vaginal balance is disrupted so that these bacteria overgrow at the expense of the protective bacteria; Lactobacillus. Lactobacilli produce hydrogen peroxide to help maintain a healthy and normal balance of microorganisms in the vaginal mucosa. Women who have been diagnosed with BV have up to 1,000 times more anaerobic bacteria than women without the disease. Instead of the normal predominance of Lactobacillus bacteria, increased numbers of organisms such as Gardnerella vaginalis, Bacteroides, Mobiluncus, and Mycoplasma hominis are found in the vagina in women with BV. The cause of this imbalance in the microflora of the vaginal mucosa is not currently known. Some studies have suggested that douching may be one cause of BV.

Diagnosis

Three of four criteria should be positive to obtain a diagnosis of BV

Treatment and Prevention

Products like douches or deodorant sprays that mask vaginal odor should not be used to treat BV. Although they may temporarily eliminate odor, they will not cure the condition. It is important to tell the patient not to douche or use a feminine hygiene spray for a few days before their appointment. These products may actually hide important clues that can help in diagnosing BV, and may make the condition worse. If the patient has BV then it can be treated with the following:metronidazole or clindamycin

Mycotic Vulvovaginitis or Vulvovaginal Candidiasis

Etiology

The causative agent of this disease is a yeast called Candida albicans.

Manifestations

The vaginal discharge frequently appears as a thick, curd like discharge containing epithelial cells and masses of hyphae/pseudohypha. The patient usually has intense pruritus of the vulva and erythematous vagina and labia.

Epidemiology

Overgrowth with C albicans is the second most common cause of vaginitis.

Pathogenesis

When the delicate balance of organisms in the vagina is upset, the yeast can overgrow and cause vaginitis. When a woman takes certain antibiotics to treat a bacterial infection, the antibiotic may also kill the lactobacilli that produce hydrogen peroxide to protect against yeast overgrowth. Other factors that may upset the balance and lead to yeast infection include pregnancy, obesity, diabetes, birth control pills, steroids, and prolonged exposure to moisture, and poor feminine hygiene.

Diagnosis

Diagnosis is frequently made based on the character of the vaginal discharge (i.e., curd-like discharge) and on other patient signs and symptoms. Grams stains and KOH treatment of the discharge can be performed to look for yeast cells and pseudohyphae.

Treatment and Prevention

Intravaginal agents like butoconazole, clotrimazole, nystatin or terconazole can be given. An oral antifungal agent fluconazole can also be given to treat this disease.

Trichomoniasis

Etiology

The etiological agent is a flagellated protozoan Trichomonas vaginalis.  It is a pear shaped organism exhibiting a characteristic motility described as a wobbling and rotating motion, recognition of this on wet mounts is important in diagnosis.

Manifestations

In females proliferation of the organisms is associated with a low-grade inflammation manifested by: itching and burning, painful urination and a frothy, green, creamy discharge, which is described as being leukorrheic and very malodorous. Because of the ease of anatomic spread to the urethra, urethritis develops and is manifested chiefly by; dysuria and increased frequency and urgency. Many women with this infection may not have any symptoms.

In males symptoms can be associated with urethritis and prostatovesiculitis however men are usually asymptomatic. If symptoms exist they include: dysuria and increased frequency and urgency. Occasionally in severe cases there is exudate formation

Epidemiology

Pathogenesis

Low-grade inflammation is associated with the presence of high numbers of trichomonads. This parasite attaches to the cells that line the surface of the vagina and produce proteases and cytotoxic toxins that cause the host cells to round up and detach. This damage results in an immunological response from the host with many PMN’s arriving at the mucosal surface of the vagina and in the vaginal discharge. These high numbers of trichomonads become established oftentimes because of a disruption of the normal flora that has allowed them to overgrow. Immunity to infection does occur but it is only partially protective against subsequent T vaginalis infections.

Diagnosis

Clinical diagnosis depends upon recognition of the symptoms of dysuria, frothy, cream, malodorous discharges associated with punctate lesions and hyperemia of the vagina. The most practical method of specific diagnosis is microscopic examination for motile trichomonads in vaginal or urethral discharges. This vaginal discharge contains many PMN’s which usually are not present in the other causes of vaginitis.

Treatment and Prevention

Metronidazole is effective in treating this infection. Most men have asymptomatic T vaginalis infections and so can give back this parasite back to their female sexual partner. The use of male condoms can lower chances of transmission from an asymptomatic male to their female sexual partner. However, the best means of avoiding reinfection is to treat the male sexual partner with metronidazole.

Differential Diagnosis of Vaginal Infections

Diagnostic Criteria
Normal
Bacterial Vaginosis
Vaginitis Trichomonas
Candida Vulvovaginitis
Vaginal pH
3.8 - 4.2
> 4.5
4.5
< 4.5 (usually)
Discharge
White,thin, flocculent
Thin, white (milky), gray
Yellow, green, frothy
White, curdy, "cottage cheese" 
Amine odor 
"whiff" test
Absent
fishy
fishy
Absent
Microscopic
Lactobacilli,
epithelial cells
Clue cells, adherent cocci, no WBC's
Trichomonads, WBC's >10/hpf 
Budding yeast, hyphae, pseudohyphae

Send comments and mail to Dr. Neal R. Chamberlain, nchamberlain@atsu.edu
Revised 9/1/04
©2004 Neal R. Chamberlain, Ph.D., All rights reserved.