Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (267 page)

   Group A
Streptococcus
,
Staphylococcus aureus
, and other pathogens may cause acute vaginal infection with pain, edema, erythema, and purulent vaginal discharge. Gram staining and culture confirm the diagnosis.

   Diagnosis: General Aspects of Vaginosis

The initial diagnostic evaluation should include a detailed history and laboratory testing. (Note that symptoms may be caused by more than one infectious condition.) A detailed clinical history may provide information that is useful in distinguishing infectious vaginitis from other conditions that may cause changes in the character of vaginal discharge (e.g., urethritis, cervicitis, noninfectious inflammatory conditions). Important factors include the following:

   Menstrual history: Vaginal secretions may vary with pregnancy and menstrual cycle. Vulvovaginal candidiasis often occurs in the premenstrual period; trichomoniasis often occurs in the postmenstrual period.

   Sexual history: Factors associated with an increased risk of STDs, including BV and trichomoniasis, include new sexual partner, exposure to multiple sexual partners, and history of STD.

   Recent and current medications: Antibiotics, estrogen and progestin drugs, and other medications may predispose to vaginitis through changes in the vaginal environment or flora.

   Personal hygiene and potential irritants: Hygienic products and practices, frequent or recent douching, soaps and detergents, topical medications, and panty liners and other products may cause vaginal irritation, resulting in symptoms indistinguishable from infectious causes.

   In addition to history and physical examination, the following tests are recommended: vaginal pH, microscopic examination of vaginal secretions (wet mount, Gram stain), and amine test. Additional testing, including testing for specific microorganisms, is recommended for patients in whom testing does not provide a diagnosis.

   Laboratory Tests

Specific diagnosis requires laboratory testing (see Table
8-1
).

   Vaginal pH: Secretions are collected, using a dry swab, from the vaginal sidewall halfway between the cervix and introitus. A narrow-range paper (pH 4.0–5.5) should be used.

   Microscopic examination: Saline wet mount preparations are used for direct detection of yeast-like cells and pseudohyphae, trichomonads, and host cells. Vaginal secretions collected by swab are suspended in a drop of normal saline on a microscopic slide. Normal vaginal secretions show a predominance of SECs with a minimal number of PMNs. Note that although
Candida
species are common components of the normal vaginal microflora, visualization of many yeast-like cells or pseudohyphae is abnormal and characteristic of candidiasis. (Detection of yeast may be facilitated by addition of 10% KOH to the saline wet mount preparation.) “Clue” cells are squamous epithelial cells covered by coccobacillary organisms, resulting in fuzzy or indistinct cell borders.

   Gram stain: Gram stains are used for direct detection of bacteria, yeast, and host cells. Normal vaginal secretions show a predominance of SECs with a minimal number of PMNs. There is a predominance of gram-positive bacilli consistent with
Lactobacillus
species.