AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

Trichomoniasis is a sexually transmitted protozoal infection caused by Trichomonas vaginalis. Women may be asymptomatic carriers, or they may experience a range of symptoms, including a mild fulminant inflammatory disease. Men are frequently asymptomatic carriers. The widespread prevalence of trichomoniasis in US and international populations and co-infection with other sexually transmitted diseases (STDs) creates an important public health concern.

Pathophysiology

T vaginalis inhabits the vaginal and urethral tissues. In women, T vaginalis is isolated from the vagina, cervix, urethra, bladder, and Bartholin and Skene glands. In men, the organism is isolated from the anterior urethra, external genitalia, prostate, epididymis, and semen. The flagellated parasite is approximately the size of a white blood cell, although size may vary based on physical conditions. Symptoms typically occur after an incubation period of 4-28 days. The protozoal pathogen causes direct damage to the epithelium, leading to microulcerations.

Frequency

United States

The Centers for Disease Control and Prevention (CDC) estimates that 7.4 million new cases of trichomoniasis occur annually. The organism also is detected in 30-40% of men who are exposed. The prevalence of T vaginalis infection at clinics treating STDs varies from 8-31%. In men, trichomoniasis may account for as many as 17% of cases of nongonococcal, nonchlamydial urethritis.

International

Trichomoniasis affects approximately 180 million women worldwide. The frequency in Europe is similar to that of the United States. In Africa, the prevalence may be much higher. Trichomoniasis was present in 65% of pregnant women attending an antenatal clinic in South Africa.

Mortality/Morbidity

• Pregnant women infected with T vaginalis are 30% more likely than uninfected women to deliver preterm or to have a low birth weight infant. They are 40% more likely to deliver a preterm, low birth weight infant.
• Complications in men include prostatitis, epididymitis, urethral stricture disease, and infertility.
• T vaginalis infection is highly associated with the presence of other STDs, such as gonorrhea, chlamydia, and HIV infection. Men with coexisting symptomatic trichomoniasis and HIV infection have a 6-fold increase in the concentration of HIV in their semen. Theoretically, this confers an increased risk of transmission of HIV to their sexual partners. Two explanations exist for the associations between T vaginalis and HIV: (1) Disruption of the epithelial monolayer leads to increased passage of the HIV virus; (2) T vaginalis induces lymphocyte activation and replication and cytokine production, and this leads to increased viral replication in HIV-infected cells.

Sex

• Symptomatic trichomoniasis occurs more commonly in women.
• Trichomoniasis infection in men is less clinically apparent; 10-50% of infected men may be asymptomatic carriers.

Age

Trichomoniasis is an STD; therefore, it is encountered in sexually active adolescents and adults.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

• Women
• • Symptoms range from none in women who are asymptomatic carriers to a severe pelvic inflammatory disease.
  • Common symptoms are yellow vaginal discharge, abnormal vaginal odor, dyspareunia, and vulvar itching.
  • Some women may experience dysuria.
• Men
• • Symptoms range from none in men who are asymptomatic carriers to urethritis complicated by prostatitis.
  • The usual incubation period for the development of symptomatic disease is 10 days or less.
  • Nongonococcal urethritis is the most typical clinical syndrome in men who are symptomatic.
  • Discharge is present in 33-50% of men who are symptomatic and varies from purulent to mucoid in character.
  • Most symptomatic infections are intermittent and self-limiting.

Physical

• Women
• • Purulent or homogenous vaginal discharge and vulvar or vaginal erythema are common.
  • Colpitis macularis, or strawberry cervix, describes a diffuse or patchy macular erythematous lesion of the cervix. This is a specific sign for trichomoniasis but is visible in only 1-2% of cases without the aid of colposcopy. With colposcopy, colpitis macularis is detected in up to 45% of cases.
  • Lower abdominal tenderness may be present; however, this is described in fewer than 10% of patients. If this occurs, coexisting salpingitis or an intra-abdominal pathology is possible.
  • Coexisting Neisseria gonorrhea infection, candidiasis, and bacterial vaginosis are common and may produce a mixed clinical picture.
• Men
• • The findings on physical examination are generally unremarkable unless the infection is complicated. It may be associated with local inflammatory states, including balanitis and balanoposthitis.
  • Physical findings of epididymitis and prostatitis also may occur.

Causes

See Pathophysiology.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Bacterial vaginosis
Atrophic vaginitis with secondary infection
Erosive lichen planus
Foreign body vaginosis

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Laboratory studies aid in demonstration of the T vaginalis organism and are used to differentiate the infection from other causes of vaginitis.
• Bedside laboratory studies
• • The vaginal pH measured on Nitrazine paper is elevated. Usually, the pH is above 5.0, and it may be as high as 6.0. Bacterial vaginosis or atrophic vaginitis also may cause elevation in the vaginal pH.
  • Upon application of 10% potassium hydroxide to a vaginal swab sample in the potassium hydroxide amine test, a fishy odor is released, which can suggest trichomoniasis or bacterial vaginosis.
• Saline microscopic examination
• • Obtaining a vaginal swab sample for saline wet mount evaluation is an easy, valuable, and economical tool for obtaining diagnosis.
  • Trichomonads, which are ovoid-shaped parasites, are slightly larger than polymorphonuclear lymphocytes (PMNs) and may be identified by their ameboid mobility. Trichomonads cause an inflammatory reaction; therefore, a large number of PMNs usually are present, and this number correlates with the severity of the infection.
  • A saline wet preparation is positive for identifying trichomonads in approximately 60% of the cases.
• Papanicolaou test
• • Trichomonads may be viewed on Papanicolaou (Pap) test, but this test has a sensitivity of only 60-70% when compared to the use of saline microscopy.
  • False-positive results are common with this technique.
• Cultures
• • Incubate the cultures anaerobically.
  • Growth is detected within 48 hours and has a sensitivity of 95%.
  • Culture is important in establishing the diagnosis in men because the wet preparation findings are often negative.
• Polymerase chain reaction
• • Polymerase chain reaction (PCR) methods reportedly have high sensitivity and specificity (97% and 98%, respectively).
  • The availability of this test may be limited.

Other Tests

• VI-SENSE
• • The US Food and Drug Administration (FDA) recently approved this self-test to facilitate the management of vaginal symptoms at home.
  • The test consists of a panty liner that facilitates preliminary diagnosis of vaginal infections (bacterial vaginosis and trichomoniasis) by measuring acidity levels.
  • A yellow chemical strip embedded in the panty liner changes color upon contact with secretion that contains an elevated pH level.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• Systemic treatment is important to ensure a cure because trichomoniasis is an infection of multiple sites (eg, vaginal epithelium, Skene glands, Bartholin glands, urethra).
• Oral metronidazole is the treatment of choice and is demonstrated in multiple studies to be superior in efficacy when compared to intravaginal treatment. Treatment failures may require a high-dose metronidazole regimen.

Diet

Instruct the patient to avoid alcohol while taking metronidazole (and for 24 h after the last dose) or tinidazole (for 72 h after the last dose), because the interaction may cause a disulfiramlike reaction.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

The 5-nitroimidazole group of drugs includes antiprotozoal effective agents, which are used for the treatment of trichomoniasis. The mechanism of action is not well understood; however, anaerobic organisms preferentially reduce the 5-nitro group, and active metabolites are likely to interact with anaerobic bacterial and protozoal DNA.

Drug Category: Antiprotozoal agents

Therapy must be comprehensive and should cover all likely pathogens in the context of this clinical setting.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Sexual partners of infected patients must be treated to prevent reinfection.
• Consider empiric treatment of other STDs that frequently coexist with trichomoniasis.
• Advise the patient to avoid intercourse until therapy is complete and the patient and partner are asymptomatic.
• Persistent treatment failures may require metronidazole susceptibility testing through the Centers for Disease Control and Prevention (CDC).

Deterrence/Prevention

• Abstinence from sexual intercourse prevents this STD.
• Condoms may protect against transmission of trichomoniasis.
• Limiting the number of sexual partners decreases risk of trichomoniasis.

Complications

• See Mortality/Morbidity.

Patient Education

• Educate the patient about STDs, including HIV, and methods of prevention.
• Discuss the side effects and interactions encountered with metronidazole.
• For excellent patient education resources, visit eMedicine's Parasites and Worms Center and Pregnancy and Reproduction Center. Also, see eMedicine's patient education article Trichomoniasis.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to treat trichomoniasis during pregnancy may result in an adverse fetal outcome. The mother should seek treatment during pregnancy. Transmission from an infected mother during delivery is rare but possible. An infected infant may present with fever. Young girls may present with vaginal discharge.
• Screen for STDs in the pregnant patient and treat appropriately.

Special Concerns

• The use of metronidazole in the first trimester of pregnancy is traditionally avoided because of concern over possible teratogenic risk. Several studies, including a large meta-analysis of pregnant women exposed to metronidazole in the first trimester, found no increased risk of birth defects. Consider this when weighing the benefits and any possible risks in treating trichomoniasis in pregnant patients.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

• ACOG Committee on Practice Bulletins--Gynecology. ACOG Practice Bulletin. Clinical management guidelines for obstetrician-gynecologists, Number 72, May 2006: Vaginitis. Obstet Gynecol. May 2006;107(5):1195-1206.
• Abramowicz M (ed.). Drugs for Parasitic Infections. The Medical Letter. Aug 2004.
• Burtin P, Taddio A, Ariburnu O. Safety of metronidazole in pregnancy: a meta-analysis. ALYSIS. Feb 1995;172(2 Pt 1):525-9. [Medline].
• Cates W Jr. Estimates of the incidence and prevalence of sexually transmitted diseases in the United States. American Social Health Association Panel. Sex Transm Dis. Apr 1999;26(4 Suppl):S2-7. [Medline].
• Centers for Disease Control and Prevention. Trichomoniasis. 2004;[Full Text].
• Centers for Disease Control and Prevention (CDC). Sexually transmitted diseases treatment guidelines 2002. Centers for Disease Control and Prevention. MMWR Recomm Rep. May 10 2002;51(RR-6):1-78. [Medline].
• Cotch MF, Pastorek JG 2nd, Nugent RP. Trichomonas vaginalis associated with low birth weight and preterm delivery. The Vaginal Infections and Prematurity Study Group. Sex Transm Dis. Jul 1997;24(6):353-60. [Medline].
• Geva A, Bornstein J, Dan M, et al. The VI-SENSE-vaginal discharge self-test to facilitate management of vaginal symptoms. Am J Obstet Gynecol. Jun 9 2006;[Full Text].
• Guenthner PC, Secor WE, Dezzutti CS. Trichomonas vaginalis-induced epithelial monolayer disruption and human immunodeficiency virus type 1 (HIV-1) replication: implications for the sexual transmission of HIV-1. Infect Immun. Jul 2005;73(7):4155-60. [Full Text].
• Haefner HK. Current evaluation and management of vulvovaginitis. Clin Obstet Gynecol. Jun 1999;42(2):184-95. [Medline].
• Krieger JN. Trichomoniasis in men: old issues and new data. Sex Transm Dis. Mar-Apr 1995;22(2):83-96. [Medline].
• Madico G, Quinn TC, Rompalo A. Diagnosis of Trichomonas vaginalis infection by PCR using vaginal swab samples. J Clin Microbiol. Nov 1998;36(11):3205-10. [Medline].
• Nanda N, Michel RG, Kurdgelashvili G, Wendel KA. Trichomoniasis and its treatment. Expert Rev Anti Infect Ther. Feb 2006;4(1):125-35.
• Redondo-Lopez V, Meriwether C, Schmitt C. Vulvovaginal candidiasis complicating recurrent bacterial vaginosis. Sex Transm Dis. Jan-Mar 1990;17(1):51-3. [Medline].
• Saurina GR, McCormack WM. Trichomoniasis in pregnancy. Sex Transm Dis. Jul 1997;24(6):361-2. [Medline].
• Sobel JD. Vaginitis. N Engl J Med. Dec 25 1997;337(26):1896-903. [Medline].
• Sobel JD. Vaginal infections in adult women. Med Clin North Am. Nov 1990;74(6):1573-602. [Medline].
• Wolner-Hanssen P, Krieger JN, Stevens CE. Clinical manifestations of vaginal trichomoniasis. JAMA. Jan 27 1989;261(4):571-6. [Medline].

Article Last Updated: Sep 18, 2006