Trichomoniasis

Trichomoniasis is one of the most common diseases of the genitourinary tract and ranks among the top STIs.

Causes of Trichomoniasis

Trichomoniasis is caused by the protozoan Trichomonas vaginalis. Most men infected with T. vaginalis are asymptomatic, although a small number develop nongonococcal urethritis. In women, most of whom are symptomatic, T. vaginalis causes a characteristic diffuse, foul-smelling, yellow-green discharge and vulvar irritation, although many women have few symptoms. Recent evidence suggests a possible association between vaginal trichomoniasis and adverse pregnancy outcomes, particularly early rupture of membranes and preterm labor.

Trichomonas vaginalis is a flagellated protozoan that causes an infection that is transmitted exclusively sexually in adults. Trichomonas is a single-celled parasite that exhibits the following symptoms:

• the ability to repeat the relief of an epithelial cell, penetrate into intercellular spaces and invaginate into the host cell;
• fix a large amount of antitrypsin on its surface, which provides protection;
• dependence of virulence on their hemolytic activity;
• infection develops only after intravaginal or intra-urstral inoculation of the microorganism;
• the presence of proteolytic enzymes on the surface of trichomonads, which contribute to significant tissue loosening and freer penetration of toxic metabolic products of accompanying flora into the intercellular spaces;
• pronounced chemotaxis of polymorphonuclear leukocytes.

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Symptoms of Trichomoniasis

Clinical manifestations in women are characterized by liquid, greenish-yellow vaginal discharge - up to 70%, foamy in 10-30% of cases. Patients note itching and burning in the vulva, dysuric phenomena, which intensify during menopause. In 30-50% of patients there are no complaints. The main lesion is the vagina, urethra, vaginal part of the cervix. The skin and mucous membranes of the labia majora, vestibule and vagina are edematous, hyperemic, covered with discharge. Liquid, purulent, foamy discharge of greenish-yellow color is characteristic. When examining in mirrors: the cervix is edematous, there are pinpoint hemorrhagic areas with signs of erosion on it. This symptom is typical for trichomoniasis and is detected in 40% of women during colposcopy.

Complications of trichomoniasis in women include vulvitis, bartholinitis, endocervicitis, rupture of the amniotic sac, premature birth and infertility.

Indications for laboratory testing for trichomoniasis in women

Change in the nature of vaginal discharge compared to the norm, detection of trichomoniasis in a sexual partner, lack of positive changes in the nature of vaginal discharge after empirical treatment, persistent vulvar itching after empirical treatment with antifungal drugs.

Clinical manifestations of trichomoniasis in men occur as a transient and asymptomatic carrier, which is observed in 10-36%. Symptomatic complaints include a burning sensation in the urethra, scanty gray or whitish-watery discharge. Dysuric phenomena are also observed.

Complications of trichomoniasis in men are diagnosed in the form of epididymitis, prostatitis, vesiculitis, urethral stricture, erectile dysfunction and infertility.

Indications for laboratory testing for trichomoniasis in men

Urethral discharge, dysuria, burning and itching in the urethra, irritation in the penis, reproductive disorders, erectile dysfunction, orchiepididymitis, prostatitis.

Classification of trichomoniasis

Depending on the duration of the disease and the intensity of the body's reaction to the introduction of the pathogen, the following forms of trichomoniasis are distinguished:

1. fresh, acute, subacute, torpid (low-symptom);
2. chronic (sluggish course and disease duration over 2 months);
3. trichomonas carriage (if trichomonads are present, there are no objective or subjective symptoms of the disease).

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Laboratory diagnostics of trichomoniasis

Microscopy of native and stained preparations is performed. In native preparations, vaginal trichomonads are defined by a pear-shaped or oval body slightly larger than a leukocyte, a characteristic jerky movement and a flagellum. The advantage of studying trichomonads in stained preparations is the possibility of studying them a long time after the material was taken. In stained preparations (methylene blue, Gram's), they have an oval, round or pear-shaped form with well-defined contours and a delicate cellular structure of the cytoplasm.

To identify the finer structure of trichomonads, more complex staining methods are used (according to Romanovsky-Giemsa, Heidenhain, Leishman). These methods allow identifying the pathogen in 40 to 80% of cases.

Cultural studies using special media can detect up to 95% of cases.

Treatment of trichomoniasis

Metronidazole (Trichopolum, Flagyl) is effective. Metronidazole is used at 0.25 g 2 times a day for 10 days; for a course - 0.5 g or the first 4 days at 0.25 g 3 times a day, the remaining 4 days - 0.25 g 2 times a day; for a course - 5.5 g. Tipidazole (Fazizhin) is prescribed once in a dose of 2.0 g (four tablets). If trichomoniasis is resistant to metronidazole, orpizole (orpidazole) is effective. For uncomplicated trichomoniasis, it is used at 1.5-2.0 g once, for complicated - 500 mg 2 times a day for 5-10 days.

Recommended treatment regimen for trichomoniasis

Metronidazole 2 g orally once.

Alternative scheme

Metronidazole 500 mg twice 2 times a day for 7 days.

In the United States, only oral metronidazole is used to treat trichomoniasis. Randomized trials have shown cure rates of approximately 90% to 95% with recommended metronidazole regimens, and treatment of sexual partners may improve this rate. Treatment of patients and sexual partners results in resolution of symptoms, microbiologic cure, and decreased transmission. Metronidazole gel has been approved for the treatment of bacterial vaginosis, but like other topical antibacterials that do not reach therapeutic levels in the urethra or Bartholin's glands, it is significantly less effective than oral metronidazole for treating trichomoniasis and is therefore not recommended for use. Several other topical antibacterials are used to treat trichomoniasis, but they are probably no more effective than metronidazole gel.

Follow-up observation

Follow-up is not necessary for men and women whose symptoms resolve after treatment or who were initially asymptomatic.

Infections caused by strains of T. vaginalis with reduced susceptibility to metronidazole may occur. However, most of these organisms were eliminated after the use of higher doses of the drug. If the treatment regimen is violated, the patient should be treated again according to the scheme: metronidazole 500 mg 2 times a day for 7 days. If the treatment is still ineffective, the patient should be given metronidazole 2 g once a day for 3-5 days.

Patients in whom infection is confirmed by culture and treatment with regimens recommended in this guideline has failed and in whom reinfection has been excluded should be referred to an expert; consultation is available from CDC. Metronidazole susceptibility testing of T. vaginalis is necessary in the evaluation of such cases.

NB! The FDA approved Flagyl 375™ - twice daily for 7 days - for the treatment of trichomoniasis based on pharmacokinetic similarity to metronidazole 250 mg three times daily for 7 days. However, there are no clinical data to support the clinical similarity of these two regimens.

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Management of sexual partners

Sexual partners should be treated. Patients should be advised to avoid sexual intercourse until cure. In the absence of microbiological confirmation of cure, this means until treatment is completed and the patient and their partners are symptom-free.

Special Notes

Allergies, intolerances and side effects

There are no effective alternative treatment regimens to metronidazole. Patients with allergy to metronidazole may be prescribed desensitization.

Pregnancy

Patients can be treated with metronidazole at a single dose of 2 g.

HIV infection

People with HIV infection and trichomoniasis should receive the same treatment as patients without HIV infection.