Trichomoniasis is unpopular, underdiagnosed, expert says
By Stacey Butterfield
“Does trichomoniasis matter?” gynecologist Paul Nyirjesy, MD, asked attendees at the American Society of Tropical Medicine and Hygiene's annual meeting, held in Philadelphia in December.
As one would expect in a session titled “Neglected Diseases of Poverty,” Dr. Nyirjesy's answer was yes. As a professor of obstetrics and gynecology and medicine at Drexel University College of Medicine in Philadelphia, he has seen patients who have suffered significantly from trichomoniasis, including a woman who reported her painful symptoms for 17 years before being diagnosed.
“She saw six different gynecologists, none of whom had come up with a diagnosis,” he said.
Trichomoniasis can also lead to a number of more serious ailments.
“It's associated with low-birth-weight infants and preterm birth,” said Dr. Nyirjesy. “There are case reports of neonatal respiratory infections. It's associated with atypical pelvic inflammatory disease and infertility, cervical intraepithelial neoplasia, postoperative infection. It's associated with increased shedding of HIV.”
Yet trichomoniasis and Trichomonas vaginalis, the protozoan that causes it, get relatively little attention.
“If you look at the Healthy People 2020 sexually transmitted diseases (STDs) objectives, which lay out our objectives for controlling STDs in the United States, trichomoniasis doesn't even get mentioned,” he said.
Epidemiology data show that trichomoniasis is more common than some better known diseases. According to the National Health and Nutrition Examination Survey, overall prevalence was 3.1% (“More than gonorrhea and chlamydia combined,” noted Dr. Nyirjesy) and even higher in black women (13.1%). Other markers of higher risk of infection include increasing age, lower educational level, poverty and douching.
Diagnosis and treatment lag behind infection rates, in part due to the difficulty of diagnosis, according to Dr. Nyirjesy.
“People think it's really easy to diagnose,” he said. “It turns out that the wet mount is way less sensitive than everybody thinks it is. The sensitivity of a wet mount is somewhere between 35% and 80%.”
The patient who had remained undiagnosed for 17 years had negative wet mounts, including the one that Dr. Nyirjesy did. But he observed a lot of white blood cells, which should be a clue.
“If you do a wet mount and you see a lot of white blood cells on microscopy, consider doing a more sensitive test,” he added.
One more sensitive testing option is the OSOM Trichomonas Rapid Test, manufactured by Sekisui Diagnostics, a monoclonal antibody test that costs about $10 and can be done in the office with results available in 10 minutes. The Affirm VPIII, manufactured by Becton Dickinson, is a nucleic acid probe that is office-based if a practice has the necessary machine or otherwise can be sent out with results back the next day. Both tests have shown about 90% sensitivity.
But the gold standard for testing is a trichomonas culture or polymerase chain reaction (PCR) test, Dr. Nyirjesy said. A culture eliminates the risk of false positives but requires a medium with a short shelf life. The PCR test, the Gen-Probe APTIMA TMA T. vaginalis analyte-specific reagent, uses the same technology and specimen types as chlamydia and gonorrhea tests.
“The problem with these current tests isn't their ability to detect trichomonas infection. The problem is that no one thinks to use them,” said Dr. Nyirjesy.
In addition to white blood cells on a wet mount, another indication for testing is chronic vulvovaginal symptoms with a history of trichomoniasis.
“A lot of patients who get referred to us with recurrent bacterial vaginosis don't have bacterial vaginosis; they actually have trichomoniasis,” he said.
Although some of the same drugs could be used to treat both conditions, the infections recur because women are often reinfected with trichomoniasis by their sexual partners. “The biggest difficulty is getting the providers who see the partners of the women with trichomoniasis to actually give them a treatment,” he said.
Seventy to 80% of male partners of infected women are infected, but accurate testing of them is difficult, requiring multiple sample sites.
“If a patient tells you, ‘Oh yeah, my partner went to his doctor and he was told he doesn't need treatment because they didn't see any trichomonas,’ don't believe it. It's very hard to really prove that a man does not have trichomonas,” said Dr. Nyirjesy.
To improve partner treatment rates, researchers have experimented with having the female patient deliver treatment to her partner, but the effort didn't have a significant effect on recurrence. Current recommendations are to individualize partner treatment based on the patient population, he noted.
Treatment, at least, is fairly simple. The standard regimen is one dose of 2 grams of metronidazole.
“It's very affordable. Even people who are poor can afford it,” said Dr. Nyirjesy. The other commonly used drug, tinidazole, is much more expensive, which can pose a problem for poor patients, he noted.
One complication with the simple treatment is metronidazole allergy, which some patients have been known to have, although there are no data on prevalence.
“It could run the gamut from flushing, urticaria, fever, all the way to angioedema and anaphylactic shock,” Dr. Nyirjesy said. The Center for Disease Control and Prevention (CDC)'s current recommendation for treating a patient with an allergy to the drug is desensitization.
The CDC also has advice on treating drug resistance, which research shows may be as high as 2.7% in vitro.
“Anecdotal evidence suggests that it may be increasing. I'm getting a lot of phone calls from providers around the country,” Dr. Nyirjesy said. “If you see somebody with metronidazole resistance, first of all, make sure the patient did not get reinfected and that she took her initial course. Then either give her a second course of metronidazole twice a day for seven days or tinidazole as a single two-gram dose.”
If that still doesn't work, a physician can try higher doses of either drug or call for help by consulting a specialist or actually calling the CDC. The number is 404-718-4141, and there is a website, Dr. Nyirjesy said.
He also made a call of his own, to the CDC and other groups that could raise the profile of trichomoniasis.
“We need screening recommendations so that health care providers can know yes, you're supposed to be checking off gonorrhea, chlamydia and trichomonas [when screening a patient for STDs],” he concluded.
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