What is the appropriate treatment for a patient with white blood cells in a wet prep, indicating a potential infection?

Treatment for White Blood Cells in Wet Prep

The appropriate treatment for a patient with white blood cells in a wet prep is metronidazole 2g as a single oral dose, which is the recommended first-line therapy for trichomoniasis, the most likely infection when white blood cells are present on wet prep examination. 1

Understanding White Blood Cells in Wet Prep

The presence of white blood cells (WBCs) in a vaginal wet preparation indicates inflammation and potential infection. According to the CDC guidelines, the presence of WBCs on saline microscopy of vaginal secretions is one of the additional criteria that support a diagnosis of infection 2. When evaluating a wet prep with WBCs, several conditions should be considered:

1. Trichomoniasis - Characterized by motile trichomonads and increased WBCs
2. Bacterial vaginosis - Characterized by clue cells (bacterial-covered epithelial cells)
3. Vulvovaginal candidiasis - Characterized by hyphae or budding yeast
4. Cervicitis/PID - Characterized by increased WBCs without other specific findings

Diagnostic Approach

When WBCs are found on wet prep, the following should be evaluated:

• Microscopic examination: Look for:

  • Moving flagellated trichomonads (trichomoniasis)
  • Clue cells (bacterial vaginosis)
  • Hyphae or budding yeast (candidiasis)
  • Elevated pH >4.5 (suggests trichomoniasis or bacterial vaginosis) 2

• Additional tests:

  • Whiff test (fishy odor with KOH indicates bacterial vaginosis)
  • Nucleic acid amplification tests for more sensitive detection of Trichomonas 2

Treatment Algorithm

1. If trichomonads are visible or suspected:

   • Metronidazole 2g orally in a single dose OR
   • Metronidazole 500mg orally twice daily for 7 days 2, 1

2. If clue cells are present (bacterial vaginosis):

   • Metronidazole 500mg orally twice daily for 7 days OR
   • Clindamycin cream 2% intravaginally at bedtime for 7 days 2

3. If yeast forms are present (vulvovaginal candidiasis):

   • Topical azole (clotrimazole, miconazole) for 3-7 days OR
   • Fluconazole 150mg orally as a single dose 2

4. If only WBCs are present without other findings:

   • Consider testing for gonorrhea and chlamydia
   • Empiric treatment may be warranted based on risk factors 2

Important Clinical Considerations

• Partner treatment: Sexual partners of patients with trichomoniasis should be treated simultaneously to prevent reinfection 1

• Follow-up: Consider follow-up testing to ensure resolution of infection, especially for recurrent cases

• Pregnancy considerations: Metronidazole 2g as a single dose is safe in pregnancy for symptomatic trichomoniasis 2, 1

• HIV infection: Patients with HIV should receive the same treatment regimen as those who are HIV-negative 2

Pitfalls and Caveats

• WBCs alone have limited diagnostic utility. In one study, vaginal WBC counts ≥11 WBCs/HPF had sensitivity of only 48.2-53.9% and specificity of 67.2-68.8% for STIs 3

• Coinfections are relatively uncommon but should be considered. A study of ED patients found that only 0.9% had bacterial vaginosis and trichomoniasis together, 0.8% had vulvovaginal candidiasis and bacterial vaginosis, and 0.1% had all three infections 4

• A normal vaginal wet prep typically shows abundant lactobacilli, no leukocytes, and mature squamous cells. The presence of WBCs disrupts this normal pattern 5

• Clue cells on wet prep are not associated with urinary tract infections, so additional testing may be needed if UTI is suspected 6

By following this evidence-based approach, clinicians can appropriately diagnose and treat patients with white blood cells on vaginal wet prep, improving outcomes and preventing complications.