What is the significance of clue cells in bacterial vaginosis (BV) diagnosis?

From the Guidelines

Clue cells are a crucial diagnostic indicator of bacterial vaginosis (BV), and their presence is a key factor in determining the need for treatment to prevent complications and improve patient outcomes. The presence of clue cells, which are vaginal epithelial cells covered with bacteria, primarily Gardnerella vaginalis, is a significant finding in the diagnosis of BV 1. Clue cells are characterized by their stippled appearance with indistinct borders when viewed under a microscope, and their presence in a vaginal smear, especially when they constitute more than 20% of epithelial cells, strongly suggests BV.

Diagnostic Criteria

The diagnosis of BV is typically made using the Amsel clinical criteria, which include:

• Vaginal pH greater than 4.7
• The presence of clue cells on wet mount
• Thin homogeneous discharge
• A fishy odor of vaginal discharge before or after addition of 10% KOH (i.e., the whiff test) 1.

Treatment and Prevention

Treatment of BV typically involves antibiotics such as metronidazole 500mg orally twice daily for 7 days, or clindamycin cream 2% intravaginally at bedtime for 7 days 1. Prompt identification of clue cells allows for appropriate treatment, preventing complications such as pelvic inflammatory disease, preterm birth, and acquisition of sexually transmitted infections, and relieving symptoms such as discharge with a fishy odor.

Clinical Considerations

It is essential to note that BV can be asymptomatic, and the presence of clue cells may be the only indication of the infection. Therefore, healthcare providers should be vigilant in diagnosing and treating BV to prevent complications and improve patient outcomes. Additionally, research has shown that BV is associated with adverse pregnancy outcomes, including preterm delivery, preterm premature rupture of membranes, spontaneous abortion, and preterm labor 1.

Key Points

• Clue cells are a key diagnostic indicator of BV
• The presence of clue cells is a significant finding in the diagnosis of BV
• Treatment of BV typically involves antibiotics such as metronidazole or clindamycin
• Prompt identification of clue cells allows for appropriate treatment, preventing complications and relieving symptoms
• Healthcare providers should be vigilant in diagnosing and treating BV to prevent complications and improve patient outcomes.

From the Research

Significance of Clue Cells

• Clue cells are epithelial cells heavily covered with adherent bacteria and are an accepted clue to the diagnosis of bacterial vaginosis 2, 3.
• The presence of clue cells is one of the four criteria used to diagnose bacterial vaginosis, along with a homogenous noninflammatory discharge, pH >4.5, and a positive whiff test 2.
• Clue cells are found in approximately 56% of cases of bacterial vaginosis, and their presence is unique to Gardnerella species 3.
• The diagnosis of bacterial vaginosis using clue cells is important, as it can help guide treatment and prevent complications such as preterm labor and pelvic inflammatory disease.

Diagnosis and Treatment of Bacterial Vaginosis

• Bacterial vaginosis can be diagnosed using a combination of clinical criteria, including the presence of clue cells, and laboratory tests such as Gram stain and pH measurement 4, 5.
• Treatment of bacterial vaginosis typically involves the use of antibiotics such as metronidazole or clindamycin, which can be administered orally or intravaginally 4, 5, 6.
• The effectiveness of treatment can be evaluated using criteria such as the presence or absence of clue cells, vaginal pH, and symptoms such as discharge and odor 4, 5.

Morphology of Clue Cells

• Clue cells can be distinguished from pseudo-clue cells, which are epithelial cells mechanically entrapped in bacterial masses 3.
• The morphology of clue cells can be evaluated using fluorescence in situ hybridization (FISH) and can provide information on the spatial distribution of bacterial taxa in vaginal discharge 3.
• The presence of true clue cells, which are characterized by direct cohesive adherence to epithelial cells, is unique to Gardnerella species and can be used to diagnose bacterial vaginosis 3.