Vaginal Infections Diagnosis and Treatment

Introduction to Vaginal Infections

• The American College of Obstetricians and Gynecologists recommends that the three most common vaginal infections, bacterial vaginosis (BV), vulvovaginal candidiasis (yeast infection), and trichomoniasis, be diagnosed and treated promptly to prevent complications 1

Bacterial Vaginosis

• Bacterial vaginosis is the most prevalent cause of vaginal discharge or malodor, resulting from replacement of normal H₂O₂-producing Lactobacillus species with an overgrowth of anaerobic bacteria, including Gardnerella vaginalis, Prevotella species, Mobiluncus species, and Mycoplasma hominis, according to the Centers for Disease Control and Prevention (CDC) 1, 2
• The diagnosis of BV requires three of four Amsel criteria, including homogeneous, white, noninflammatory discharge, clue cells on microscopic examination, vaginal pH >4.5, and positive whiff test, as recommended by the CDC 1
• The CDC recommends metronidazole as first-line therapy for BV, with tinidazole as an alternative 1, 2
• Treating male partners does not prevent recurrence of BV, as it represents dysbiosis rather than simple sexual transmission, according to the CDC 1, 2

Vulvovaginal Candidiasis

• The CDC recommends that vulvovaginal candidiasis be diagnosed based on clinical presentation, including thick, white "curdled" or cottage cheese-like discharge, intense vulvar pruritus, and normal vaginal pH, with microscopic examination revealing budding yeast or pseudohyphae 1

Trichomoniasis

• Trichomoniasis is a sexually transmitted protozoal infection caused by Trichomonas vaginalis, characterized by a frothy greenish discharge with prominent itching, according to the CDC 3
• The CDC recommends metronidazole as the treatment for trichomoniasis, with tinidazole as an alternative, and emphasizes the importance of treating sexual partners simultaneously to prevent reinfection 3

Diagnostic Approach

• A pelvic examination with office laboratory testing is essential for accurate diagnosis of vaginal infections, as symptoms and physical examination alone are inadequate, according to the American College of Obstetricians and Gynecologists 1
• The CDC recommends essential office tests, including vaginal pH testing, wet mount examination, KOH preparation, and microscopic examination, to diagnose vaginal infections 1, 4

Evaluation and Diagnosis of Green Vaginal Discharge

Primary Etiology: Trichomoniasis

Secondary Etiology: Cervicitis Mimicking Green Discharge

Diagnostic Algorithm for Green Discharge

Management and Clinical Implications of Trichomoniasis

Treatment Recommendations

• For adults diagnosed with Trichomonas vaginalis infection, the CDC recommends a single oral dose of metronidazole 2 g to achieve microbiologic cure. 8

Partner Management

• All sexual partners of a patient with confirmed trichomoniasis should receive the same metronidazole 2 g single‑dose regimen concurrently to prevent reinfection. 8

Sexual Activity Guidance

• Patients should refrain from sexual intercourse until both the patient and their treated partner have completed therapy and are asymptomatic, in order to avoid transmission and recurrence. 8

Associated Risks

• Trichomoniasis infection is linked to an increased risk of HIV acquisition and transmission, as well as adverse pregnancy outcomes such as preterm delivery and premature rupture of membranes. 9

CDC‑Recommended Guidance for Vaginal Trichomoniasis and Its Differential Diagnosis

Diagnostic Differentiation

• Candida vaginitis maintains a normal vaginal pH (≈3.8–4.2), whereas trichomoniasis raises the pH above 4.5, helping clinicians distinguish the two infections. [CDC 2002] 10
• Bacterial vaginosis typically presents with a thin, homogeneous white‑ or gray‑colored discharge, which contrasts with the green‑yellow purulent discharge of trichomoniasis. [CDC 1993] 11
• Bacterial vaginosis is associated with a characteristic fishy odor (positive whiff test) and the presence of clue cells on microscopy, findings that are absent in trichomoniasis, which instead shows erythematous macular lesions. [CDC 1993] 11
• Bacterial vaginosis is a non‑inflammatory condition and does not produce punctate hemorrhagic (“strawberry cervix”) lesions, a hallmark of trichomoniasis. [CDC 1993] 11

Treatment Recommendations

• Administer metronidazole 2 g orally as a single dose to achieve microbiologic cure of Trichomonas vaginalis infection; this regimen is endorsed by CDC guidelines as the preferred first‑line therapy. [CDC 2002] 10
• Advise patients to abstain from sexual intercourse until both the patient and their sexual partner have completed therapy and are asymptomatic, to prevent reinfection and further transmission. [CDC 2002] 10

Pregnancy Considerations

• Trichomoniasis in pregnancy is linked to adverse outcomes such as preterm delivery and premature rupture of membranes; CDC recommends the same 2 g single‑dose metronidazole regimen, which is considered safe for use during pregnancy. [CDC 2002] 10