Vaginitis ========= þ BV Bacterial Vaginosis Amsel criteria (3 of 4) Thin, homogenous vaginal discharge Clue cells (+)whiff test (fishy odor on KOH prep) pH >4.5 "Clinical diagnosis of bacterial vaginosis was considered positive if two of the following three criteria were met: vaginal pH exceeded 4.5, whiff test was positive, and clue cells were present on wet smear preparation. The character of vaginal secretion was not used as in the Amsel criteria because discharge in pregnant women is less easily characterized than in nonpregnant women" [Mastrobattista JM, Bishop KD, Newton ER. Wet smear compared with gram stain diagnosis of bacterial vaginosis in asymptomatic pregnant women. Obstet Gynecol. 2000 Oct;96(4):504-6.] Gardnerella vaginalis, a catalase-negative, oxidase-negative, non-spore-forming bacillus. On Gram stain, it appears as pleomorphic gram-variable coccobacilli. It is normal vaginal flora in many women, and it is also found in the distal urethra of many men. G. vaginalis is occasionally associated with urinary tract infections, and, rarely, with bacteremia; however, it is best known for its association with bacterial vaginosis. Bacterial vaginosis, or BV, is the most common vaginal infection in women of childbearing age. Although it does not cause complications in most cases, BV is associated with significant health risks. Women who have BV are at increased risk for pelvic inflammatory disease, ectopic pregnancy, and infertility. Pregnant women who have BV are more likely to have babies born prematurely or with low birth weight. BV is associated with an increased susceptibility to infection with HIV and other sexually transmitted diseases, such as chlamydia and gonorrhea. BV is also associated with an increased risk that an HIV-infected woman will pass HIV to her partner. Despite research spanning nearly five decades, the cause of BV is still not fully understood. In 1955, Gardner and Dukes published results suggesting BV was caused by the bacterium now known as Gardnerella vaginalis, and for many years the condition was referred to as Gardnerella vaginalis vaginitis. Studies done since 1955 have shown that G. vaginalis is present as normal flora in many women, so clearly it is not the sole cause of BV. Researchers now believe BV results from a disruption of normal vaginal flora that involves a loss of lactobacilli and a corresponding overgrowth of G. vaginalis, Mycoplasma hominis, and anaerobes such as Prevotella spp., Bacteroides ureolyticus, Fusobacterium nucleatum, and Mobiluncus. Because G. vaginalis is present in almost 100% of women with BV, it likely has a role in the development of the condition. Researchers now suspect a more important bacterium is Mobiluncus, an anaerobic Gram-negative bacillus usually present in the rectum. Mobiluncus is commonly found in the vaginal secretions of patients with BV, but it is almost never found in patients without BV. Because G. vaginalis is present as normal flora in up to 58% of asymptomatic women, culture is of little value in the diagnosis of BV. In fact, studies have shown that the predictive value of a positive culture for G. vaginalis is less than 50%. For this reason, culture is no longer recommended as a diagnostic tool for BV. Instead, clinicians now diagnose BV when at least three of the following four criteria are present: • Thin, homogeneous, noninflammatory vaginal discharge • “Fishy” odor when 10% potassium hydroxide is added to vaginal secretions (positive “whiff test”) • Vaginal pH greater than 4.5 • Presence of clue cells in vaginal fluid Of these, the criterion most specific for BV is the presence of clue cells. Clue cells are vaginal epithelial cells that are covered with bacteria, including G. vaginalis, Mobiluncus, and others. On a wet mount, clue cells appear stippled, glittery, or granular with fuzzy, indistinct edges. To diagnose BV, more than 20% of the vaginal epithelial cells should be clue cells. In 1991, Nugent et al published a standardized method for scoring Gram stains for BV. With Nugent’s method, a Gram-stained smear of vaginal secretions is examined for the presence of three morphotypes: 1) large, parallel-sided Gram-positive rods (lactobacillus-like); 2) curved Gram-negative rods (Mobiluncus-like); and 3) a combination of tiny, Gram-variable coccobacilli and rounded, pleomorphic Gram- negative rods with vacuoles (Gardnerella/Bacteroides-like). Based on the average number of organisms seen per field, each morphotype is assigned a score ranging from 0 to 4. The three scores are then added together. A total score of 7-10 is diagnostic for BV. A table that describes the scoring system can be found in reference 2, p 377 (Forbes et al). Since 1991, studies have clearly established the value of a Gram stain examination of vaginal fluid in the diagnosis of BV. Nugent’s standardized method readily shows the loss of lactobacilli and concurrent overgrowth of G. vaginalis and anaerobes that characterize BV. A Gram stain also confirms the presence of clue cells seen on a wet mount. Finally, Gram stains are easily prepared; they can be quickly screened; and they provide a permanent record. B. EXAMINATION 1) Epithelial Cells - large rounded cells with sharp, wispy, well defined edges 2) WBC's - smaller, rounded cells with a normal ratio of "WBC : Epi of < 1" 3) Normal Vaginal Flora - predominantly very small rod shaped lactobacilli with notable BROWNIAN MOTION that stain Gram positive (purple) 4) Vaginitis Examination - 3 MAIN CAUSES: 1) Bacterial vaginosis > 2) Candidiasis > 3) Trichomoniasis (these 3 conditions account for > 90% all cases of vaginitis) MIMICKING CONDITIONS: 1) Mucopurulent cervicitis (2/ to gonorrhea, chlamydia, or herpes) 2) Excessive normal secretions (These later 2 conditions combined with the 3 main causes of vaginitis account for approximately 95% of all vaginal complaints) III. BACTERIAL VAGINOSIS - BV is a disturbance of the vaginal microbial ecosystem rather than a true infection - There is little inflammation and few white blood cells - Loss of predominant lactobacilli - Massive overgrowth of coccobacillary mixed flora including: Gardnerella vaginalis + mobiluncus + bacteroides + peptostreptococci + genital mycoplasmas, and more 4 DIAGNOSTIC CRITERIA: 1) Thin gray vaginal discharge 2) Vaginal pH > 4.5 (Swab middle 1/3 of vagina. Avoid cervix & blood.) 3) Positive 10% KOH Whiff/Sniff Test = fishy odor of volatile amines {3 MAJOR AMINES: Cadaverine, Putrescine, Trimethylamine} 4) Clue Cells - vaginal epithelial cells covered with adherent bacteria - Epi's = granular & stippled with loss of clear cell borders - Up to 30% of normal women can have clue cells - Up to 30% of culture positive cases may NOT have clues - Gardnerella vaginalis is the most common adherent bacteria but organisms such as mobiluncus and others do adhere - FALSE CLUE CELLS = epi's with adherent lactobacilli - > 20% of all cells must be CLUE CELLS to be diagnostic - Mobiluncus are smaller than lactobacilli, curved, and are motile 2 STRAINS: 1) Mobiluncus curtisii - Gram variable 2) Mobiluncus mulieris - Gram negative, slightly larger - they have active corkscrew and spinning motions - REMEMBER there are usually FEW white blood cells present in BV. If there are many WBC's suspect a mixed infection (eg., gonorrheal or chlamydial cervicitis) 3 IV. CANDIDIASIS (YEAST) - Yeast is a fungal infection caused by Candida albicans in most cases - It presents as single oval blastospores, replicating budding yeast, & as invasive pseudohyphae - The intestinal reservoir allows vaginal cross contamination & asymptomatic colonization - Under certain conditions the blastospore germinates producing invasive pseudohyphae - Pseudohyphae invade & cause symptoms; cell damage & sloughing obscure the pseudohyphae - 10% KOH Prep - make epithelial cell walls transparent and the pseudohyphae easier to see - Yeast has highly adherent cottage cheese-like plaques attached to the vaginal walls - Candida albicans stains Gram positive (purple) and identifies well via this method - WBC's are often present and vary directly with the degree of invasion & inflammation V. TRICHOMONIASIS - Trichomoniasis is a protozoal infection caused by the ovoid Trichomonas vaginalis - Trichomonads are motile with ameboid characteristics, have an undulating membrane, 4 highly active beating anterior flagella, & a stiff posterior axostyle - Trichomonads are very inflammatory to the vaginal mucosa leading to many WBC's - "COLPITIS MACULARIS" or the "STRAWBERRY CERVIX" = punctate cervical hemorrhages 2/ to inflammation - Vaginal discharge is often copious, yellow-green, and frothy - Dry slides kill and pin the trichomonads making them indistinguishable from WBC's RULE OF THUMB - err on the side of too much rather than too little normal saline GONORRHEA - highly associated with Trichomoniasis and also causes many WBC's - remember to check for GC by Gram stain and/or culture - GC is a Gram negative (red to pale pink), very small diplococci found within the WBC's þ Vaginal pH - Normal vaginal fluid and candidal discharge typically has a pH of 3.8-4.2, whereas bacterial vaginosis typically causes a discharge with a pH of 5-6, and trichomonas discharge typically has a pH of 6-7. 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