Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (268 page)

   Amine “whiff” test: A drop of 10% KOH may be added to vaginal secretions on a microscopic slide. The immediate release of a “fishy” (volatile amine) odor is typical of BV.

   Culture: Culture of vaginal secretions may improve the sensitivity of detection for trichomoniasis, but special techniques are required for isolation of
T. vaginalis
. Culture is not recommended for routine evaluation of vulvovaginal candidiasis. Positive cultures for yeast must be interpreted with caution because
C. albicans
and other yeast may represent normal endogenous flora. Culture may be useful for patients with recurrent vulvovaginal candidiasis, or candidiasis resistant to standard therapy. Bacterial culture, including culture for
G. vaginalis
, is not reliable for the diagnosis of BV because no single organism can be specifically implicated in the pathogenesis of BV.

   Serology: Serologic testing does not play a significant role in the diagnosis of vaginitis.

   Molecular tests: Molecular diagnostic tests are increasingly available for the diagnosis of infectious vaginitis. For example, nucleic acid hybridization provided greater sensitivity for detection of agents associated with BV, trichomoniasis, and vulvovaginal candidiasis compared with standard methods.

   HIV and syphilis serology and testing related to other STIs should be considered.

   Diagnosis

   Common presenting symptoms of vaginitis include change in the volume, character or odor of vaginal secretions; irritation of the genital mucosa, including erythema, burning, and itching; dysuria; and spotting.

   In premenopausal women, the volume of vaginal secretions is <5 mL/day. Secretions are typically odorless, transparent, and viscous and white to yellowish. Normal vaginal pH is 4.0–4.5. Microscopic examination demonstrates a predominance of normal squamous epithelial cells (SECs) and few PMNs; there is a predominance of gram-positive bacilli consistent with lactobacilli (long, slender, may form chains).

TABLE 8–1. Comparison of Various Causes of Vaginitis

↓, decreased;↑, increased; PMN/EC, ratio of polymorphonuclear cells to epithelial cells.

   Douching within 24 hours decreases the sensitivity of tests. Do not test during first few days of menstrual cycle.

Bacterial Vaginosis

   Bacterial vaginosis (BV) is a common cause of infectious vaginitis, accounting for approximately 50% of cases. BV is associated with sexual transmission. BV is caused by a disruption of the normal microbial flora of the vagina. Gram stain shows a loss of the predominant
Lactobacillus
species, which produce peroxide and acidify the vaginal secretions. Loss of the lactobacilli allows overgrowth of anaerobes and other microorganisms, including
Gardnerella
and
Mobiluncus
,
Atopobium vaginae
, and other species.

   Patients with BV may be asymptomatic or present with minimal symptoms. Typical symptoms include an increase in the volume of thin, homogeneous, often malodorous vaginal secretions. Signs of inflammation are minimal.