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 foundthe 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 bethe 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 aw it out. So when we talk about the pathophysiology of a disease, we'retalking about the mechanism by which that disease occurs. Soorder to understandthe pathophysiology of bacterial vaginosis, we need to take a look at a sample of bacteria
that existsthe vagina. So I'll aw out someGardnerella vaginalis bacteria, and so I'll put this upour key. This is the symbol forGardnerella vaginalis. And I'll aw a few of them around here, but I also wanna show that there are a lot of other bacteriathat existthis sample. So if you really look at it here,
Vaginitis Candida BV Trichomoniasis Wet Mount Whiff Test Vaginal pH Trich Albicans gardnerella
Distinguished future physicians welcome toStomp on Step 1 the only free tutorials series that helps you study more efficiently by focusingon the highest yield material. I'm Brian McDaniel and I will be your guide on thisjourney through vulvovaginal infections. This is the 3rd tutorialmy playlist covering allof microbio. Vulvovaginitis (AKA Vaginitis) is inflammationof the lower genital tract. It is usually due to infection, but there are a wide varietyof causes. During this tutorial we will focus on the 3 most important causes of vulvovaginitisfor the medical board exam (trichomonas, candida and BV). However, you should know that othertypes of vaginitis include mechanical irritation,
allergic reactions (to soaps or feminine products)and a variety of other infections. Atrophic Vaginitis is a common cause of vaginitis inpostmenopausal women and we will cover thata later tutorialthe GYN section. Gonorrheaand Chlamydia present primarily with cervicitis, but it can also cause vulvovaginitis. GCwill be covered laterits own tutorial. We will start with a few different tests thatwe will use to differentiate between the different infections.Wet Prep (AKA Wet Mount Test) is a microscopic examination of vaginal discharge used to differentiatebetween different types of vulvovaginitis. The vaginal specimen is obtained using a speculumand a que tip similar to how one gets a pap
smear. Then the specimen is rubbed onto aglass slide. One half of the slide has a op of saline added to it while the other halfof the slide has a op of 1020% KOH (Potassium hyoxide) added to it.When Saline is added it makes it easier to view clue cells for BV flagellated motilecells for trichomonas. The KOH kills bacteria and vaginal cells leavingonly yeast cells. This makes it easier to view the psuedohyphae and budding yeast presentduring vulvovaginal candidiasis. KOH is also alkalotic so it can be used fora â€œWhiff Test.â€� In this scenario when the alkalotic KOH is added to a sample containingBV it will create an amine or fishy smell.
This is a similar principle behind how thesmell of BV can increase after unprotected sex since semen is alkalotic. The normal vaginal pH for a reproductive agewoman is about 4, while the normal vaginal pH before puberty and after menopause is about7. During puberty there is an estrogen guided increasethe growth lactobacilli flora.These bacteria break down glycogen into lactic acid which lowers pH from about 7 to about4. Now that you know the normal values you can apply it to diseases. Usually, BacterialVaginosis Trichomonas have alkalotic pH (gt;4.5reproductive age women) while candidahas normal pH (lt;4.5). pH paper can be tested
by using pH paper on vaginal discharge. You can see here at the top right corner thatI give BV a high yield rating of 3 on a scale from 1 to 10. If you want to learn more about that ratingsystem you can go to my website or click on this orange box here if you are watching thistutorial on a computer. Bacterial Vaginosis (AKA BV) is a polymicrobialinfection caused by the overgrowth of normal flora. The key bacteriathis infectionis gram negative Gardnerella Vaginalis. Clue cells are visible on the saline portionof a wet prep. A Clue Cell is a sloughed mucosal
squamous epithelial cell coveredmany adherentcoccoid bacteria (Gardenerella Vaginalis). Here is a picture comparing normal squamousepithelial cells with a few stered lactobacill to squamous cells that are coveredthousandsof adherent garenerella bacteria. Here is one more pic. You can see on the leftwe have a normal squamos epithelial cell with a few WBCs. On the right we have the darkerClue cells. Finally I have a photomicrograph to look atin case you see that on your test. A thinwatery graywhite discharge is presentA fouls smell is present and often described as an Amine Odor or Fishy Smell. This smellis intensified after unprotected intercourse
Examination of Vaginal Wet Preps
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 aidthe 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 magnifiion.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 microscopea 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 hyoxide, or KOH, prep. When the vaginal sample was collected,the swab was placeda test tube with approximately half a milliliter of saline. So, for the salineprep, you only have to take a op 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 op of the vaginal sample on another slide and add one op 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. Keepmind 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 cellsfoundthe vagina. They're large, flat cells with a small nucleus and a large area of cytoplasm.Note that there is some granularitythe 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 indie infection. Trichomonads are pearshaped protozoa whichmove by means of flagella. Trichomonads are similarsize 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 itsand. Cluecells are associated with bacterial vaginosis, a conditionwhich the normal microbialflora of the vagina is disrupted. Yeast may be foundtwo 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 yeastsaline, but sometimesit's hidden by epithelial cells or by PMNs. Red blood cells, sperm, and bacteria can alsobe seen.