6 | Diagnosis of Infections During Gynecologic Examination |
Colposcopy
Colposcopy allows for better observation of the epithelium, thus making it possible to evaluate any efflorescence and to detect small parasites. The acetic acid test (3–5%) should be used not only for assessing the vaginal portion of the cervix, but also when findings on the vulva are not clear (though not in the case of rhagades). Dysplasia, such as Bowen disease and subclinical HPV infections, become visible only this way and can therefore be easily distinguished from lichen simplex or lichen sclerosus.
Measuring the pH of the Discharge
(Special indicator paper for pH 4.0–4.7, Merck.)
This is part of every gynecological examination because it tells something about the bacterial colonization of the vagina. A pH value of < 4.5 means that lactobacilli are present, since only they produce lactic acid and can still multiply at this pH. It also means that the normal protective flora is present, which—depending on estrogen levels—largely keeps the vagina free of germs derived from the perianal region during times of severe strain (Table 6.1, Figs. 6.1–6.3).
Table 6.1 Significance of the pH value of discharge
Range of pH value | Significance |
|---|---|
pH 3.8–4.2 | Many lactobacilli, possibly yeast infections |
pH 4.3–4.7 | Few lactobacilli, slightly mixed flora (may include yeasts), possibly leukocytosis |
pH 4.8–5.5 | Disturbed vaginal flora (mixed flora) suspected, bacterial vaginosis, trichomoniasis, status post antibiotics (when lactobacilli are no longer present), severe leukocytosis |
pH > 6.0 | Atrophic vaginitis, amniorrhexis during pregnancy, condition of a girl prior to estrogen production; this is also the pH of cervical secretion |
Test for Amines
A drop of 10% potassium hydroxide solution is added to the discharge collected on a cotton swab or microscopic slide. This intensifies the characteristic fishy odor (amines) in the case of bacterial vaginosis. However, this effect may be limited to specific instances.
Microscopy
For microscopic examination, the discharge is spread onto a microscopic slide and stained and then viewed in oil, or in solution under a cover slip. Alternatively, the discharge is first diluted and then viewed as so-called wet mount. Specific sampling of the discharge is easily performed with the wooden handle of a cotton probe, which is then stirred into a drop of methylene blue solution (0.1 %) on a slide. The mildly microbicidal methylene blue provides a better contrast if the flora is disturbed (with the higher pH resulting in better staining) and prevents contamination of the diluting solution. However, if trichomonads are suspected (yellow discharge), sodium chloride solution should be used instead of methylene blue solution; otherwise the trichomonads lose their vitality too quickly.
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