Trichomoniasis : Clinical Aspects

TRICHOMONIASIS :CLINICAL ASPECTS

MANIFESTATIONS

In women, T. vaginalis produces a persistent vaginitis. Although up to 50% are asympto-matic at the time of diagnosis, most develop clinical manifestations within 6 months. Ap-proximately 75% develop a discharge, which is typically accompanied by vulvar itching or burning (50%), dyspareunia (50%), dysuria (50%), and a disagreeable odor (10%). Al-though fluctuating in intensity, symptoms usually persist for weeks or months. Com-monly, manifestations worsen during menses and pregnancy. Eventually, the discharge subsides, even though the patient may continue to harbor the parasite. In symptomatic pa-tients, physical examination reveals reddened vaginal and endocervical mucosa. In severe cases, petechial hemorrhages and extensive erosions are present. A red, granular, friable endocervix (strawberry cervix) is a characteristic but uncommon finding. An abundant discharge is generally seen pooled in the posterior vaginal fornix. Although classically de-scribed as thin, yellow, and frothy in character, the discharge more frequently lacks these characteristics. Recent studies have demonstrated that trichomoniasis both increases the risk of preterm birth and enhances susceptibility to human immunodeficiency virus (HIV) infections.

The urethra and prostate are the usual sites of infection in men; the seminal vesicles and epididymis may be involved on occasion. Infections are usually asymptomatic, possi-bly because of the efficiency with which the organisms are removed from the urogenital tract by voided urine. Symptomatic men complain of recurrent dysuria and scant, nonpu-rulent discharge. Acute purulent urethritis has been reported rarely. Trichomoniasis should be suspected in men presenting with nongonococcal urethritis, or a history of ei-ther prior trichomonal infection or recent exposure to trichomoniasis.

DIAGNOSIS

The diagnosis of trichomoniasis rests on the detection and morphologic identification of the organism in the genital tract. Identification is accomplished most easily by examining a wet mount preparation for the presence of motile organisms. In women, a drop of vaginal discharge is the most appropriate specimen; in men, urethral exudate or urine sediment after prostate massage may be used. Although highly specific when positive, wet mounts have a sensitivity of only 50 to 60%. They are most likely to be negative in asymptomatic or mildly symptomatic patients and in women who have douched in the previous 24 hours. Giemsa- and Papanicolaou-stained smears provide little additional help. The recent intro-duction of a commercial system that allows direct, rapid microscopic examination without the need for daily sampling may ameliorate this situation. Direct immunofluorescent antibody staining has a sensitivity of 70 to 90%. Parasitic culture, while more sensitive, re-quires several days to complete and is frequently unavailable.

TREATMENT

Oral metronidazole is extremely effective in recommended dosage, curing more than 95% of all infections. It may be given as a single dose or over 7 days. Simultaneous treatment of sexual partners may minimize recurrent infections, particularly when single-dose therapy is used for the index case. Because of the disulfiram-like activity of metronidazole, alco-hol consumption should be suspended during treatment. The drug should never be usedduring the first trimester of pregnancy because of its potential teratogenic activity. Use in last two trimesters is unlikely to be hazardous but should be reserved for patients whose symptoms cannot be adequately controlled with local therapies. High-dose, long-term metronidazole treatment has been shown to be carcinogenic in rodents. No associa-tion with human malignancy has been described to date, and in the absence of a suitable alternative drug, metronidazole continues to be used.