What are the symptoms and treatment options for Trichomonas vaginalis infection in sexually active individuals?

Trichomonas Vaginalis: Symptoms and Treatment

Recommended Treatment

Treat all patients with Trichomonas vaginalis infection with oral metronidazole 500 mg twice daily for 7 days, and simultaneously treat all sexual partners with the same regimen to achieve cure rates of 90-95% and prevent reinfection. 1, 2, 3

Clinical Presentation

In Women

• Many women (up to 50%) are asymptomatic, making screening essential in at-risk populations 4
• Symptomatic women present with:
  • Diffuse, malodorous, yellow-green vaginal discharge 1
  • Vulvar irritation and itching 1
  • Vaginal soreness 5
  • Dyspareunia (painful intercourse) 5

In Men

• Most men are asymptomatic, serving as efficient vectors for transmission without knowing they carry the infection 1, 4
• Symptomatic men may develop:
  • Nongonococcal urethritis 1
  • Urethral discharge (typically milky white and fluid) 6
  • Urethral irritation 6
  • Symptoms persisting for more than 4 weeks in 78% of cases 6

Treatment Algorithm

First-Line Therapy

• Metronidazole 500 mg orally twice daily for 7 days (preferred regimen) 2, 3, 7
• This extended regimen is critical because Trichomonas persists in the urethra and perivaginal glands, requiring sustained therapeutic drug levels 2, 3
• Achieves cure rates of 90-95% 1

Alternative Regimen (When Adherence is Concern)

• Metronidazole 2 g orally as single dose 3, 8
• However, recent evidence shows this single-dose regimen has higher failure rates in women compared to the 7-day regimen 7
• Single-dose remains preferred treatment in men 7

Alternative Agent

• Tinidazole 2 g orally as single dose can be used as an alternative 9

Critical Management Steps

Partner Treatment (Non-Negotiable)

• All sexual partners must be treated simultaneously with the same regimen, regardless of symptoms 1, 2, 3
• Male partners often harbor asymptomatic urethral infection serving as reinfection reservoir 2
• Patients must abstain from sexual activity until both partners complete treatment and are asymptomatic 1, 3

Treatment Failure Protocol

1. First failure: Re-treat with metronidazole 500 mg twice daily for 7 days, ensuring partner treatment 2, 3
2. Repeated failure: Metronidazole 2 g once daily for 3-5 days 2, 3
3. Persistent failure: Consider susceptibility testing of T. vaginalis to metronidazole 2

Common Pitfalls to Avoid

Never Use Topical Metronidazole

• Topical metronidazole gel has less than 50% efficacy because it cannot achieve therapeutic levels in the urethra or perivaginal glands 3
• Only oral therapy is appropriate 3

Alcohol Avoidance

• Patients must avoid alcohol during treatment and for at least 24 hours after completion due to disulfiram-like reaction causing nausea, vomiting, flushing, headache, and abdominal cramps 3

Follow-Up

• Routine follow-up is unnecessary for patients who become asymptomatic after treatment 1, 3
• However, rescreening at 3 months is recommended due to high rates of repeat and persistent infections 7

Special Populations

Pregnant Women

• Symptomatic pregnant women should be treated because trichomoniasis is associated with:
  • Premature rupture of membranes 1, 3
  • Preterm delivery 1, 3
  • Low birth weight 1
• Treatment: Metronidazole 2 g orally as single dose after first trimester 2, 3
• Metronidazole 500 mg twice daily for 7 days can also be used 2

HIV-Positive Patients

• Use the same treatment regimen as HIV-negative patients 1, 2, 3
• Treatment is particularly important as T. vaginalis infection increases HIV acquisition risk 4, 7

Metronidazole Allergy

• Desensitization may be required as effective alternatives are extremely limited 2, 3

Clinical Significance Beyond Symptoms

Trichomoniasis has serious health consequences including:

• Facilitation of HIV transmission and acquisition 4, 7
• Increased risk of cervical cancer 4, 7
• Adverse pregnancy outcomes (premature rupture of membranes, preterm delivery, low birth weight) 1, 4, 3, 7
• Postabortal and postcesarean infection 10
• Pelvic inflammatory disease 5