Bacterial vaginosis: Introduction, clue cell significance and Amsel criteria

Bacterial vaginosis: Introduction, Clue Cell Significance and Amsel Criteria for Diagnosis

Bacterial vaginosis vaginal discharge showing clue cells

Introduction of Bacterial vaginosis

Bacterial vaginosis is a common reproductive tract infection. It is caused by different bacteria, leading to many complications such as miscarriage, premature rupture of membrane, post-partum endometritis, and still birth. Abnormal vaginal flora can emerge as a risk factor for intraepithelial neoplasia and cervical cancer. Abnormal vaginal flora can emerge as a risk factor for intraepithelial neoplasia and cervical cancer. Bacterial vaginosis has been defined as a polymicrobial alteration in vaginal flora causing an increase in vaginal pH, sometimes associated with a homogenous discharge, but in the absence of a demonstrable inflammatory response. It is associated with an increased vaginal pH and massive overgrowth of vaginal anaerobes such as Gardnerella vaginalis, Mycoplasma hominis, Bacteroides species. These anaerobes produce large amounts of proteolytic carboxylic enzymes, which break down vaginal peptides into a variety of amines that are volatile, malodors, and associated with increased vaginal transudation and squamous epithelial cell exfoliation, resulting in clue cells seen in the typical clinical features observed in patients with bacterial vaginosis. The most common presenting symptom in bacterial vaginosis is an uncharacteristic vaginal discharge that is homogeneous inconsistency and grayish-white in color, and that will react positively with the amine test, emit a foul, fishy odor. Other symptoms may include vaginal itching and irritation, dyspareunia, and pelvic pain. Although it is not itself considered to be a sexually transmitted disease, it can be associated with diseases such as gonorrhea and chlamydia. PAP (Papanicolaou )stained smears show clue cells, which is a characteristic feature of bacterial vaginosis. Clue cells surface covered with huge bacterial population is also stained by Gram’s stain.

Clue cells significance for Bacterial vaginosis

Clue cells are vaginal squamous epithelial cells coated with anaerobic Gram-variable coccobacilli Gardnerella vaginalis and granular appearance in direct wet mount microscopic examination. Clue cells were first described by Gardner and Dukes in 1955 and were so named as these cells give an important “clue” to the diagnosis of bacterial vaginosis (BV). The sensitivity and specificity of more than 20% clue cells on the wet mount for diagnosis of bacterial vaginosis were 87% and 94%. The normal vaginal squamous epithelial cells have distinct cell margins and lack granularity. Clue cells are seen as squamous epithelial cells with a large number of coccobacillus organisms densely attached in clusters to their surfaces, giving them a granular appearance. The edges of squamous epithelial cells, which normally have a sharply defined cell border, become indistinct or stippled. Polymorphonuclear leukocytes (PMNs) can also be demonstrated on the normal vaginal wet mount preparation. The vaginal discharge of patients with bacterial vaginosis is notable for its lack of PMNs, typically 1 or less than 1 PMN per vaginal epithelial cell. The prevalence of BV is high in women with Pelvic inflammatory disease( PID), and in one prospective study, BV was predictive of subsequent PID associated with gonorrhea or Chlamydia. In pregnancy bacterial vaginosis is associated with late miscarriage, preterm birth, preterm premature rupture of membranes, and postpartum endometritis. The disease is often asymptomatic and in many patients, the diagnosis is made during a routine examination or cytology.

Amsel criteria for diagnosis for Bacterial vaginosis

The clinical composite criteria for the diagnosis of bacterial vaginosis were developed by Amsel and colleagues. Amsel’s Criteria: At least three of the four criteria are present for the diagnosis to be confirmed.

Increased amounts of thin, homogeneous, grayish-white
Adherent vaginal discharge with a characteristic
Fishy smell
Vaginal pH higher than 4.5
A smell of amine before or after the addition of Potassium hydroxide
Presence of clue cells.

Note:- Microscopic detection of clue cells more than 20% in vaginal discharge is the most useful single procedure for the diagnosis of bacterial vaginosis.

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