What is the diagnosis for a positive vaginal wet prep showing clue cells?

Bacterial Vaginosis

The diagnosis is bacterial vaginosis (BV). Clue cells on vaginal wet prep are pathognomonic for this condition and represent one of the four Amsel diagnostic criteria. 1

Understanding the Diagnosis

Clue cells are vaginal epithelial cells with bacteria adhered to their surface, creating a stippled appearance with obscured cell borders, and they are the hallmark microscopic finding of bacterial vaginosis. 2 These bacterial-covered epithelial cells are easily identified on saline wet mount preparation and serve as a key diagnostic feature. 1

Complete Diagnostic Criteria (Amsel Criteria)

While clue cells alone strongly suggest BV, the CDC recommends confirming the diagnosis when at least 3 of the following 4 criteria are present: 1, 2

• Homogeneous, white, noninflammatory discharge that smoothly coats the vaginal walls 1
• Presence of clue cells on microscopic examination (which you already have) 1
• Vaginal pH greater than 4.5 (normal is <4.5) 1
• Positive whiff test - fishy odor when vaginal secretions are mixed with 10% KOH, due to amines present in the discharge 1

Pathophysiology

BV results from replacement of the normal H₂O₂-producing Lactobacillus species in the vagina with high concentrations of anaerobic bacteria (Prevotella, Bacteroides, Mobiluncus species), Gardnerella vaginalis, and Mycoplasma hominis. 1, 3 This is the most prevalent cause of vaginal discharge or malodor, though up to 50% of women may be asymptomatic. 1, 3

Treatment Recommendations

When to Treat

All women with symptomatic disease require treatment, as the principal goal is to relieve vaginal symptoms and signs. 4, 3 However, asymptomatic women generally do not require treatment unless they fall into specific high-risk categories. 4

High-Risk Situations Requiring Treatment Even if Asymptomatic:

• Before surgical abortion procedures - treatment substantially reduces post-abortion pelvic inflammatory disease 4, 2
• Before hysterectomy or other invasive gynecological procedures - due to increased risk of postoperative infectious complications 4, 2
• Pregnant women with history of preterm delivery - may reduce risk of prematurity 4, 2

First-Line Treatment Regimens

Metronidazole 500 mg orally twice daily for 7 days is the recommended treatment with a 95% cure rate. 4, 3

Alternative regimens include: 4, 3

• Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days
• Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days
• Metronidazole 2g orally as a single dose (84% cure rate) - useful when compliance is a concern 4

Critical Clinical Considerations

Important Warnings

• Patients using metronidazole must avoid alcohol during treatment and for 24 hours afterward due to potential disulfiram-like reaction 4, 3
• Clindamycin cream is oil-based and might weaken latex condoms and diaphragms 4, 3
• Treatment of male sex partners has NOT been shown to prevent recurrence of BV 1, 3

Common Pitfalls to Avoid

• Missing the diagnosis before invasive procedures - failing to identify and treat BV increases risk of post-procedure infections including endometritis, PID, and vaginal cuff cellulitis 3, 2
• Overlooking BV in pregnant women - BV is associated with premature rupture of membranes, preterm labor, preterm birth, and postpartum endometritis 3
• Expecting permanent cure - BV has a high recurrence rate of 50-80% within one year, which may necessitate repeated treatments 3, 2

Additional Diagnostic Notes

If microscopy is unavailable or the evaluator is inexperienced, Gram stain can be used as an alternative diagnostic method by determining the relative concentration of bacterial morphotypes characteristic of BV. 1 Culture of G. vaginalis is NOT recommended as it lacks specificity (positive predictive value <50%). 1