Infectious Disease · Gynecologic Infections
The facts most likely to be tested
Trichomonas vaginalis is a flagellated, motile protozoan transmitted via sexual contact.
Patients typically present with profuse, thin, yellow-green, frothy vaginal discharge and vulvar pruritus.
Physical examination reveals a strawberry cervix (punctate cervical hemorrhages) due to capillary dilation.
Wet mount microscopy demonstrates motile trichomonads as the diagnostic gold standard.
Vaginal pH is characteristically elevated (>4.5), similar to bacterial vaginosis.
First-line treatment for both the patient and all sexual partners is oral metronidazole.
Patients must be advised to avoid alcohol during treatment and for 24-48 hours after completion due to the disulfiram-like effect.
Vignette unlocked
A 26-year-old female presents to the clinic complaining of a persistent, foul-smelling vaginal discharge for one week. She reports associated vulvar itching and mild dysuria. On pelvic examination, the vaginal mucosa is erythematous, and the cervix displays punctate cervical hemorrhages described as a strawberry cervix. A saline wet mount of the discharge reveals motile, pear-shaped organisms. The vaginal pH is 5.2.
What is the most appropriate treatment for this patient and her sexual partner?
Oral metronidazole
The clinical presentation of a strawberry cervix and motile organisms on wet mount is pathognomonic for Trichomoniasis, which requires systemic treatment with metronidazole for the patient and all sexual partners.
Full handout
High yield triage
Etiology / Epidemiology
Caused by Trichomonas vaginalis, a flagellated protozoan. Primary STI risk factors include multiple partners and lack of barrier protection.
Clinical Manifestations
Presents with copious, frothy, yellow-green discharge and the pathognomonic strawberry cervix (punctate hemorrhages).
Diagnosis
Gold standard is NAAT (nucleic acid amplification test). Wet mount shows motile trichomonads.
Treatment
First-line is Metronidazole 2g orally in a single dose. Avoid alcohol during treatment.
Prognosis
High rate of reinfection; requires partner treatment to prevent recurrence.
Full handout
Epidemiology & Etiology
This is the most common non-viral STI worldwide. It is caused by the anaerobic, motile protozoan Trichomonas vaginalis. Transmission occurs via sexual intercourse, with high prevalence in patients with other concurrent STIs.
Pertinent Anatomy
The organism primarily colonizes the urogenital tract, specifically the vagina, Skene's glands, and urethra. Infection is often multifocal, explaining why vaginal treatment alone is insufficient.
Pathophysiology
The parasite adheres to the vaginal epithelium, causing micro-ulcerations and inflammation. This disrupts the normal vaginal flora, often leading to an elevated pH > 4.5. The inflammatory response results in the characteristic discharge and friability of the cervical mucosa.
Clinical Manifestations
Patients often report a malodorous, yellow-green discharge and intense vulvar pruritus. The strawberry cervix (colpitis macularis) is the pathognomonic finding on speculum exam. Dysuria and dyspareunia are common, while many patients remain asymptomatic.
Diagnosis
The NAAT is the most sensitive and specific diagnostic test. A saline wet mount demonstrating motile trichomonads is diagnostic but has low sensitivity. A vaginal pH > 4.5 is a classic, though non-specific, clinical finding.
Treatment
Metronidazole 2g orally as a single dose is the first-line therapy. Disulfiram-like reaction occurs if alcohol is consumed within 48 hours of ingestion. Tinidazole is an alternative. All sexual partners must be treated simultaneously to prevent the high risk of reinfection.
Prognosis
Untreated infection is associated with preterm birth and low birth weight in pregnant patients. There is also an increased risk of HIV acquisition. Patients should be re-tested 3 months post-treatment due to high reinfection rates.
Differential Diagnosis
Bacterial Vaginosis: Clue cells and positive whiff test
Candida Vaginitis: Thick, white, curdy discharge with pH < 4.5
Atrophic Vaginitis: Occurs in postmenopausal women with low estrogen
Gonorrhea/Chlamydia: Often presents with cervicitis and mucopurulent discharge
Allergic Contact Dermatitis: History of new soaps or hygiene products