music It's a typical day. A patient has noticedsome itching, or maybe an unpleasant vaginal odor. During her exam, the ian willcheck vaginal pH, examine any discharge that's present, and collect a sample. Then, it'son to the microscope. music This is where you'll gather more specificinformationabout what's causing those vaginal symptoms. We'll show you how to prepare andexamine vaginal wet preps and how to do a whiff test. The results, combined with the patient's vaginal pH test, will aid in the diagnosis.
Under the microscope, you'll be looking for trichomonads, yeast, and the clue cells associated with bacterial vaginosis. We'll show you how to recognize them. music First, the microscope itself: This is a compoundlight microscope. It has several objective lenses on a rotating mount. For our purpose,one of these has to be a 10x low power objective, and one has to be a 40x for greater magnification.This flat part, under the objectives, is the stage. Under the stage is the condenser. Belowthat, at the base of the microscope, is the light source. There are two knobs that controlfocus; one for coarse adjustment and one for
fine adjustment. And these are the oculars,or eyepieces. We'll come back to the microscope in a minute, but first, let's look at how to prepare wet mount slides. The complete vaginal wet mount involves botha saline prep and a potassium hydroxide, or KOH, prep. When the vaginal sample was collected,the swab was placed in a test tube with approximately half a milliliter of saline. So, for the salineprep, you only have to take a drop of the suspension and place it on a slide. Add acoverslip, being careful to avoid trapping air bubbles. Your saline slide is ready.Place a second drop of the vaginal sample on another slide and add one drop of 10 percentKOH. Sniff the preparation immediately, using
your hand to waft any odor toward your nose.This is the whiff test. Note if there's a fishy or amine odor. Then add a coverslip,avoiding air bubbles. Keep in mind that you must work quickly to prepare and examine thewet mounts. That's because trichomonads may lose their characteristic motility within15 to 20 minutes. Before we move on now, though, let's lookat the cast of characters you may discover. These are normal squamous epithelial cellsfound in the vagina. They're large, flat cells with a small nucleus and a large area of cytoplasm.Note that there is some granularity in the cytoplasm.
Polymorphonuclear leukocytes are known asPolys, or PMNs. They may also be called white blood cells, or WBCs. These are small roundcells. Several lobes of the nucleus are visible within the surrounding cell cytoplasm. Findingmany PMNs may indicate infection. Trichomonads are pearshaped protozoa whichmove by means of flagella. Trichomonads are similar in size to PMNs and are identifiedby their characteristic jerking movement. The actual flagella may be too thin and toorapidlymoving to be seen. A clue cell is a squamous epithelial cellcoated with enough small bacteria that at least 75 percent of the cell's border is obliterated.It may look as if someone has spread glue
over the cell and pressed it in sand. Cluecells are associated with bacterial vaginosis, a condition in which the normal microbialflora of the vagina is disrupted. Yeast may be found in two forms. Pseudohyphaeare the long, tubular, branching forms. Budding yeast are paired yeast cells that resemblea shoe print. The larger part is the sole and the smaller bud is the heel of the shoe. The saline prep will allow you to see epithelialcells, PMNs, trichomonads, and clue cells. You can also see yeast in saline, but sometimesit's hidden by epithelial cells or by PMNs. Red blood cells, sperm, and bacteria can alsobe seen.
What is bacterial vaginosis
Bacterialvaginosis is a disease that's caused by the overgrowth of a type of bacteria that's called Gardnerella vaginalis, Gardnerella vaginalis. And as the name might suggest, this is the most common vaginal infection. Now I wanna put these really big quotes
around the term infection because the thing that's interesting about Gardnerella vaginalis is that it's a bacteriathat's naturally found in the vagina. Now some may consider this to be a sexually transmitted infection, which is interestingbecause it doesn't cause
any problems until there'stoo much of it there. So when we look to the causes of bacterial vaginosis, they are all things that change the vaginal environment. That can include acts like douching, so douching, or rinsing of the vagina. The other is having newor multiple sex partners.
And finally, another known cause is the use of antibiotics. This could be in the case of somebody that has a throat infection or a pneumonia that's on antibiotics which will then attackthe bacteria that exists within the vagina andallow Gardnerella vaginalis to overgrow and cause bacterial vaginosis.
So we've touched a little bit on it here, but I wanna draw it out. So when we talk about the pathophysiology of a disease, we'retalking about the mechanism by which that disease occurs. So in order to understandthe pathophysiology of bacterial vaginosis, we need to take a look at a sample of bacteria
that exists in the vagina. So I'll draw out someGardnerella vaginalis bacteria, and so I'll put this up in our key. This is the symbol forGardnerella vaginalis. And I'll draw a few of them around here, but I also wanna show that there are a lot of other bacteriathat exist in this sample. So if you really look at it here,