Differences Between Cytolytic Vaginosis and Bacterial Vaginosis
Cytolytic vaginosis and bacterial vaginosis are distinct vaginal conditions with opposite microbiological profiles, different diagnostic criteria, and contrasting treatment approaches. 1, 2
Microbiological Differences
Bacterial Vaginosis (BV): Characterized by replacement of normal H₂O₂-producing Lactobacillus species with high concentrations of anaerobic bacteria (Prevotella sp., Mobiluncus sp.), Gardnerella vaginalis, and Mycoplasma hominis 3
Cytolytic Vaginosis (CV): Characterized by an overgrowth of lactobacilli in the vaginal flora, leading to cytolysis (breakdown) of vaginal epithelial cells 1, 2
Diagnostic Criteria
Bacterial Vaginosis
BV can be diagnosed using clinical criteria (Amsel criteria) requiring three of the following:
- Homogeneous, white, non-inflammatory discharge that smoothly coats vaginal walls 3
- Presence of clue cells on microscopic examination 3
- Vaginal fluid pH greater than 4.5 3
- Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test) 3
Cytolytic Vaginosis
CV is diagnosed based on:
- Vaginal pH ≤ 4.5 (acidic) 1, 2
- Large number of lactobacilli on Gram staining 1, 4
- Presence of false clue cells 1
- Cytolysis in vaginal epithelial cells 1, 4
- Absence or deficiency of leukocytes 1, 2
- Absence of Trichomonas, BV, or vulvovaginal candidiasis 1, 2
Clinical Presentation
Bacterial Vaginosis
- Most prevalent cause of vaginal discharge and malodor 3
- Up to 50% of women with BV may be asymptomatic 3
- Characteristic fishy odor 3
- Not typically associated with significant vulvar irritation 3
Cytolytic Vaginosis
- Presents with discharge, itching, dyspareunia, and dysuria 1, 5
- Often has a cyclical pattern with symptoms worsening during luteal phase of menstrual cycle 5, 2
- No fishy odor 2
- Often misdiagnosed as vulvovaginal candidiasis due to similar symptoms 4, 5
Treatment Approaches
Bacterial Vaginosis
- Treated with antibiotics such as metronidazole (500 mg orally twice daily for 7 days) or clindamycin 3, 6
- High recurrence rate (50-80% within a year) 6
- Treatment of male sexual partners not beneficial in preventing recurrence 3
Cytolytic Vaginosis
- No antimicrobial treatment required 1
- Managed with alkalinizing measures such as sodium bicarbonate (baking soda) sitz baths or douches to raise vaginal pH 4, 2
- Discontinuation of antifungal agents that may have been inappropriately prescribed 5
- Using pads instead of tampons during menstruation 5
Clinical Significance and Pitfalls
- CV is frequently misdiagnosed as vulvovaginal candidiasis, leading to inappropriate and ineffective antifungal treatment 4, 5
- Proper microscopic examination is crucial for differentiating between these conditions 1, 2
- BV is associated with increased risk for PID, preterm birth, and increased susceptibility to STIs, while CV is not associated with these complications 3, 6
- CV has been reported in approximately 1.7-19.4% of women with vaginitis symptoms, making it an important differential diagnosis 1, 4
Diagnostic Pearls
- The pH test is a key differentiator: BV typically has pH > 4.5, while CV has pH ≤ 4.5 3, 1
- Microscopic examination reveals opposite findings: BV shows few lactobacilli and many anaerobes, while CV shows abundant lactobacilli 1, 2
- The presence of epithelial cytolysis has high specificity (99%) for CV 1
- False clue cells in CV may be confused with true clue cells in BV, requiring careful microscopic assessment 1