What is the recommended evaluation and management for a woman presenting with vaginal discharge?

Management of Vaginal Discharge

For a woman presenting with vaginal discharge, perform point-of-care microscopy with saline wet mount, KOH preparation, and pH testing to differentiate between bacterial vaginosis (40-50% of cases), vulvovaginal candidiasis (20-25%), and trichomoniasis (15-20%), then treat based on specific diagnosis rather than empirically. 1, 2

Initial Diagnostic Evaluation

Essential Bedside Tests

• Measure vaginal pH using litmus paper: pH >4.5 suggests bacterial vaginosis or trichomoniasis, while pH <4.5 indicates candidiasis 1, 2
• Perform saline wet mount immediately to identify clue cells (bacterial vaginosis), motile trichomonads (trichomoniasis), or white blood cells 3, 2
• Perform KOH preparation to identify fungal hyphae or budding yeast (candidiasis) and conduct the "whiff test" for fishy odor (bacterial vaginosis) 1, 2
• Examine discharge characteristics: homogeneous white discharge coating vaginal walls (bacterial vaginosis), thick white cottage cheese-like discharge (candidiasis), or yellow-green frothy discharge (trichomoniasis) 1, 4

Critical Pitfall to Avoid

Never treat empirically without microscopy, as this leads to inappropriate antibiotic use, treatment failures, and missed diagnoses—the cost of pH testing and microscopy is far lower than repeat visits and complications from wrong treatment 5, 1

Bacterial Vaginosis (Most Common Cause)

Diagnosis

• Requires 3 of 4 Amsel criteria: homogeneous white discharge, clue cells on microscopy, vaginal pH >4.5, and positive whiff test (fishy odor with KOH) 1, 6
• If wet mount is equivocal, obtain Gram stain with Nugent scoring (90% sensitivity, most specific method)—standard clinical testing misses 20-30% of BV cases 7, 1
• Clue cells alone are insufficient for diagnosis; verify at least two additional Amsel criteria to avoid misdiagnosis 1

Treatment

• Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) is first-line therapy for symptomatic women 1, 6
• Avoid single-dose metronidazole 2g as first-line—it has inferior cure rates (84% vs 95%) 1
• Alternative regimens: metronidazole gel 0.75% intravaginally once daily for 5 days, or clindamycin cream 2% intravaginally for 7 days 6
• Counsel patients to avoid alcohol during metronidazole treatment and for 24 hours after (disulfiram-like reaction risk) 6
• Do not treat male partners—this does not prevent BV recurrence 6

Special Considerations

• BV recurs in 50-80% of women within one year, necessitating repeated evaluation if symptoms return 1, 7
• Treat before invasive gynecological procedures (abortion, hysterectomy, IUD insertion) to substantially reduce post-procedure pelvic inflammatory disease 1, 6

Vulvovaginal Candidiasis

Uncomplicated VVC

• Presents with vulvovaginal pruritus, erythema, and white discharge; pH typically <4.5 3, 2
• Treat with short-course topical azoles (3-7 days)—achieves symptom relief and negative cultures in 80-90% of patients 3
• Follow-up only if symptoms persist or recur within 2 months 3
• Partner treatment may be considered only in women with recurrent infection 3

Complicated VVC

• Defined as: recurrent (≥4 episodes/year), severe symptoms, non-albicans species, or occurring in pregnant/diabetic/immunosuppressed women 3
• Requires longer initial therapy to achieve remission, followed by maintenance regimen (clotrimazole, fluconazole, or itraconazole) for 6 months 3
• In pregnancy: use only 7-day topical azole therapies (oral agents contraindicated) 3
• In HIV-infected women: treat identically to HIV-negative women 3

Trichomoniasis

Diagnosis and Treatment

• Wet mount sensitivity is only 40-80%, so obtain nucleic acid amplification testing (NAAT) if clinical suspicion is high despite negative microscopy 1
• Treat with metronidazole (specific regimens per CDC guidelines) 3, 2
• Always treat sexual partners and test for concurrent STIs (gonorrhea, chlamydia) 3

Pelvic Inflammatory Disease (When Discharge Accompanies Pelvic Pain)

When to Suspect PID

Initiate empiric PID treatment in sexually active women at STI risk if uterine/adnexal tenderness OR cervical motion tenderness is present and no other cause is identified 3

Additional Supportive Criteria

• Oral temperature >38.3°C (101°F) 3
• Mucopurulent cervical discharge 3
• White blood cells on saline microscopy 3
• Elevated ESR or C-reactive protein 3
• Laboratory-documented cervical infection with N. gonorrhoeae or C. trachomatis 3

Critical Management Points

• If cervical discharge appears normal AND no WBCs on wet prep, PID is unlikely—investigate alternative causes 3
• Provide broad-spectrum coverage of N. gonorrhoeae, C. trachomatis, anaerobes, gram-negative bacteria, and streptococci 3
• Hospitalize if no improvement within 72 hours of oral therapy for parenteral treatment and possible surgical intervention 3
• Always treat male partners who had contact within 60 days before symptom onset 3
• Pregnant women with suspected PID require hospitalization and parenteral antibiotics due to high risk of maternal morbidity, fetal wastage, and preterm delivery 3

When Initial Testing is Negative

Missed Bacterial Vaginosis

• Laboratory testing fails to identify the cause in a substantial minority of women—missed BV is the most likely explanation 7
• Retest using Gram stain with Nugent criteria (90% sensitivity), as standard clinical testing misses 20-30% of BV cases 7
• Up to 50% of women with BV are asymptomatic, so infection can be present without classic symptoms 6, 7

Aerobic Vaginitis

• If confirmed by culture, treat with ampicillin or amoxicillin-clavulanate (not metronidazole) 1, 7

Important Caveat

Do not treat asymptomatic patients with incidental bacterial findings and no clue cells—this leads to inappropriate antibiotic use without clinical benefit 1, 7