Trichomoniasis overview

# Overview
Trichomoniasis is a common sexually transmitted disease that affects 7.4 million previously unaffected Americans each year. Trichomonas vaginalis, the causative agent of trichomoniasis, is an anaerobic, flagellated protozoan parasite. Trichomonas vaginalis was first discovered by Dr. Alfred Francois Donne, a French physician, in 1836.  The parasite is sexually transmitted through contact with an infected partner. Women can acquire the disease from infected men or women, but men usually contract it only from infected women. Trichomoniasis is primarily an infection of the genitourinary tract. The urethra is the most common site of infection in men, and the vagina is the most common site of infection in women. Trichomoniasis must be differentiated from other causes of vaginitis such as bacterial vaginosis, vulvovaginal candidiasis, and atrophic vaginitis. In 2008, the incidence of trichomoniasis was estimated to be 358 cases per 100,000 individuals in the United States. Females are more commonly affected with trichomoniasis than males.  Common risk factors in the development of trichomoniasis include multiple sexual partners, unprotected sexual activity, intravenous drug use, and coexisting veneral disease. If left untreated, women with trichomoniasis may progress to develop infection of the adnexa, endometrium, and Skene and Bartholin glands. In men, untreated trichomoniasis can cause epididymitis, prostatitis, and decreased sperm cell motility. Complications of trichomoniasis include pelvic inflammatory disease, increased risk of HIV, increased risk of cervical cancer, increased risk of prostate cancer, and pregnancy-related complications such as low birth weight, preterm delivery, and premature rupture of membranes. The prognosis of trichomoniasis is generally excellent with treatment. The majority of women (85%) and men (77%) with trichomoniasis are asymptomatic. One-third of asymptomatic women become symptomatic within 6 months. Common symptoms of trichomoniasis in women include vaginal discharge (which is often diffuse, malodorous, and yellow-green or gray in color), painful urination (dysuria), vulvar irritation and itching, abdominal pain, and discomfort during sexual intercourse. Symptoms of trichomoniasis in men include clear or mucopurulent urethral discharge, painful urination, and pruritus or a burning sensation following sexual intercourse. Common physical examination findings of trichomoniasis include strawberry cervix and a foul-smelling, frothy, and mucopurulent green or gray vaginal discharge. In males, there may be scanty, mucopurulent urethral discharge. Laboratory tests used in the diagnosis of trichomoniasis include saline microscopy, culture, and nucleic acid amplification tests (NAATs). Antimicrobial therapy is the mainstay of treatment for trichomoniasis.

# Historical Perspective
Trichomonas vaginalis was first discovered by Dr. Alfred Francois Donne, a French physician, in 1836.

# Pathophysiology
Trichomonas vaginalis, the causative agent of trichomoniasis, is an anaerobic, flagellated protozoan parasite. The parasite is sexually transmitted through contact with an infected partner. Women can acquire the disease from infected men or women, but men usually contract it only from infected women.

# Causes
Trichomoniasis is caused by the single-celled protozoan parasite Trichomonas vaginalis. The vagina is the most common site of infection in women, and the urethra is the most common site of infection in men.

# Differential Diagnosis
Trichomoniasis must be differentiated from other causes of vaginitis such as bacterial vaginosis, vulvovaginal candidiasis, and atrophic vaginitis.

# Epidemiology and Demographics
Trichomoniasis is the most common curable STD in young, sexually active women. An estimated 7.4 million new cases occur each year in the United States. In 2008, the incidence of trichomoniasis was estimated to be 358 cases per 100,000 individuals in the United States. Females are more commonly affected with trichomoniasis than males. Trichomoniasis usually affects African American individuals. Caucasian individuals are less likely to develop trichomoniasis. In the United States, the highest prevalence of trichomonas infection in women is observed among African-Americans, with rates ranging from 1351%.

# Risk Factors
Common risk factors in the development of trichomoniasis include multiple sexual partners, unprotected sexual activity, intravenous drug use, and coexisting veneral disease.

# Natural History, Complications, and Prognosis
If left untreated, women with trichomoniasis may progress to develop infections of the adnexa, endometrium, and Skene and Bartholin glands. In men, untreated trichomoniasis can cause epididymitis, prostatitis, and decreased sperm cell motility. Complications of trichomoniasis include pelvic inflammatory disease, increased risk of HIV, increased risk of cervical cancer, increased risk of prostate cancer, and pregnancy-related complications such as low birth weight, preterm delivery, and premature rupture of membranes. The prognosis of trichomoniasis is generally excellent with treatment.

# Diagnosis

## History and Symptoms
It is critical to collect a detailed and thorough sexual history from the patient. Specific areas of focus when obtaining a history from the patient include number and type of sexual partners (new, casual, or regular), contraception use, and previous history of trichomoniasis or other sexually transmitted diseases. The majority of women (85%) and men (77%) with trichomoniasis are asymptomatic. One-third of asymptomatic women become symptomatic within 6 months. Common symptoms of trichomoniasis in women include vaginal discharge (which is often diffuse, malodorous, and yellow-green or gray in color), painful urination (dysuria), vulvar irritation and itching, abdominal pain, and discomfort during sexual intercourse. Symptoms of trichomoniasis in men include clear or mucopurulent urethral discharge, painful urination, and pruritus or a burning sensation following sexual intercourse.

## Physical Examination
Patients with trichomoniasis are usually appear well. Common physical examination findings of trichomoniasis include strawberry cervix and a foul-smelling, frothy, and mucopurulent green or gray vaginal discharge. In males, there may be scanty, mucopurulent urethral discharge.

## Laboratory Findings
Laboratory tests used in the diagnosis of trichomoniasis include saline microscopy, culture, and nucleic acid amplification tests (NAATs).

# Treatment

## Medical Therapy
Trichomoniasis can usually be cured with the prescription drug metronidazole, administered orally in a single dose. The symptoms of trichomoniasis in infected men may disappear within a few weeks without treatment. However, an infected maneven a man who has never had symptoms or whose symptoms have stoppedcan continue to infect or re-infect a female partner until he has been treated. Therefore, both partners should be treated at the same time to eliminate the parasite. Persons being treated for trichomoniasis should avoid sex until they and their sex partners complete treatment and have no symptoms. Metronidazole can be used by pregnant women. Having had trichomoniasis once does not protect a person from getting it again. Following successful treatment, people can still be susceptible to re-infection.

## Primary Prevention
One effective measure for the primary prevention of trichomoniasis is abstinence from sexual contact.  Latex male condoms, when used correctly and consistently, can reduce the risk of transmission of trichomoniasis. Any genital symptom such as discharge, burning during urination, or an unusual sore or rash should be taken as a signal to stop having sex and to consult one's health care provider immediately.