Bacterial vaginosis

Introduction to bacterial vaginosis In recent years, it is believed that the occurrence of bacterial vaginosis (BV) is due to vaginal flora imbalance, and the reduction of lactobacilli causes the proliferation of other pathogens such as Gardnerella, various anaerobic bacteria, Vibrio curvus, etc. BV is actually A mixed infection based on Gardnerella. Since its publication in 1954, it has been called Haemophilus vaginitis, Corynebacterium vaginitis and non-specific vaginitis because of its unclear understanding of its pathogens. It was officially named BV at the special international conference in Sweden in 1984. basic knowledge Sickness ratio: 0.1% Susceptible people: women Mode of infection: non-infectious Complications: pelvic inflammatory disease endometritis cervical cancer infertility

Cause of bacterial vaginosis

Endogenous infection (90%):

Bacterial vaginosis (BV) is generally caused by a single pathogen, but is the result of a combination of multiple pathogenic bacteria. BV is an endogenous infection caused by a disorder of the ecological balance of the normal vaginal flora. Lactobacillus producing hydrogen peroxide predominates. In bacterial vaginosis, the number of lactobacilli that produce hydrogen peroxide in the vagina is reduced and other microorganisms multiply, mainly Gardnerella vaginalis (GV), anaerobic bacteria ( Ureaplasma urealyticum, with nucleic acid bacteria, Streptococcus faecium, Plasmodium, Actinobacillus sp., and human mycoplasma, of which most of the anaerobic bacteria, but promote the transformation of the normal vaginal flora, the development of BV The factors are still unclear.

Pathogenesis:

Lactobacillus, especially hydrogen peroxide-producing lactobacilli, is critical to maintaining the ecological environment of the normal vagina. When it is significantly reduced or disappeared, Gardnerella, anaerobic bacteria, Bacteroides, and Mycoplasma hominis proliferate. The number can be increased by 100 to 1000 times, resulting in a decrease in the concentration of lactate, including cytotoxin, sialidase, mucopolysaccharidase and collagenase, amines (cadaverine, putrescine, trimethylamine), organic acids and The increase of some enzymes (mucopolysaccharidase, sialidase, phospholipase, IgA protease, etc.) can increase vaginal secretions and have odor. BV pathogens can produce virulence factors to cause epithelial cell damage, causing fluid to seep out. And vaginal squamous epithelial cells fall off, producing a typical BV secretion, bacteria such as Gardnerella attached to the detached vaginal epithelial cells to form clue cells, when the biochemical components of vaginal secretions change correspondingly, the pH value rises. The alkaline environment is not conducive to the adhesion and growth of Lactobacillus, which is conducive to the growth of anaerobic bacteria such as Gardnerella, which causes bacterial vaginosis, and the incidence of pregnant women is high. Estrogen levels associated, wherein the pathological inflammatory lesions and no leukocyte infiltration, organic acids and enzymes can destroy the host defense mechanisms, such as dissolving cervical mucus, can promote microbial into the upper genital tract, causing inflammation of the genital tract.

Bacterial vaginosis prevention

Pay attention to hygiene, enhance physical fitness, actively treat, and prevent complications. Pay attention to personal hygiene during pregnancy and maintain vulvovaginal hygiene. The method of teaching patients to self-care, keep the vulva clean and dry, and avoid cross-infection. Eat more fresh vegetables and fruits to keep the stool smooth; drink plenty of water to prevent urinary tract infections.

Bacterial vaginosis complications Complications pelvic inflammatory disease endometritis cervical cancer infertility

1. Pelvic inflammatory disease: Surgery confirmed that the most frequently isolated flora in the upper genital tract secretions of women with pelvic inflammatory disease is consistent with the bacterial vaginosis, and 61.8% of patients with pelvic inflammatory disease and bacterial vaginosis.

2. Abnormal uterine bleeding and endometritis: abnormal uterine bleeding is often caused by endometritis, endometritis causes abnormal uterine bleeding and infected endometrium abnormal response to ovarian hormone or endometrial infection Or direct damage to inflammation, oral administration of metronidazole in patients with bacterial vaginosis, can quickly relieve uterine bleeding.

3. Infection after gynecological surgery: In women who have terminated pregnancy, the incidence of pelvic inflammatory disease in women with pregnancy-induced bacterial vaginosis is 3.7 times that of women without bacterial vaginosis. Oral metronidazole is used to treat bacteria in women with surgical abortion. Sexual vaginosis can reduce the incidence of postoperative pelvic inflammatory disease by 70%. Patients with bacterial vaginosis have an increased risk of vaginal rupture of cellulitis, pelvic abscess or both.

4. Cervical cancer: bacterial vaginosis, cervical intraepithelial neoplasia and genital human papillomavirus infection have the same epidemiological characteristics, anaerobic metabolism of bacterial vaginosis can produce amines and carcinogenic effects Nitroamine, a bacterial vaginosis patient with high concentrations of phospholipase C and A2 in the vaginal secretions, which increases the susceptibility of human papillomavirus infection, which may play a role in the transformation of cervical epithelial cells.

5. HIV infection: Bacterial vaginosis can increase the risk of HIV (human immunodeficiency virus) transmission between heterosexuals. When the pH increases, HIV's viability and adhesion capacity increase, and may make the spread easier. Bacterial vaginosis can alter other physicochemical properties of vaginal secretions that alter the host's defense mechanisms and increase HIV susceptibility.

6. Infertility and abortion: The incidence of tubal factor infertility is increased in patients with bacterial vaginosis. In the treatment of assisted pregnancy, the rate of embryo implantation in patients with bacterial vaginosis and non-bacterial vaginosis is similar, but bacterial vaginosis The rate of abortion in early pregnancy is higher than in non-bacterial vaginal diseases.

7. Amniotic chorioamnion, premature rupture of membranes, premature delivery and low birth weight infants: bacterial vaginal bacteria in the vagina can enter the amniotic membrane through the membrane, leading to amnion and amnion chorioamnion, and can be further developed into a fetus Premature rupture of membranes, premature delivery and delivery of low birth weight infants.

8. Postpartum endometritis and post-cesarean wound infection: The incidence of abdominal wound infection and endometritis in patients with bacterial vaginosis after cesarean delivery is higher than that of patients with non-bacterial vaginosis. Vaginal bacteria associated with bacterial vaginosis can often be cultured in endometritis.

Symptoms of bacterial vaginosis Common symptoms Increased vaginal discharge Itching vaginal discharge genital burning irritating leucorrhea brown urinary pain edema vaginal ulcer mold infection sexual intercourse difficulties

About 50% of patients with BV have no obvious symptoms. Most patients have no inflammation such as congestion and erythema in the vulva and vaginal mucosa. Symptoms are mainly characterized by increased vaginal secretions, thin or homogeneous, or grayish or gray. Yellow, fishy smell, increased after sexual intercourse, may be accompanied by mild genital itching or burning sensation, some people may have lower abdominal pain, difficulty in sexual intercourse or dysuria, only 7% of the signs, there may be vaginal mucosa Mild edema, redness, occasionally visible bleeding points, increased vaginal secretions, secretions are grayish white, uniform, often adhered to the vaginal wall, but the viscosity is very low, easy to wipe the secretions from the vaginal wall, because the performance is smooth Oil, it is called "oily leucorrhea", there are also 10% ~ 15% of patients with small foamy vaginal discharge, easy to be confused with trichomoniasis infection, BV can have periodic recurrence, often appear after the menstrual period.

Bacterial vaginosis examination

1. Ammonia test (whiff test) positive vaginal secretions plus 10% potassium hydroxide release a special unpleasant "fishy smell" or ammonia smell is positive for ammonia test, lack of ammonia taste does not rule out bacterial vaginosis.

2. Vaginal pH>4.5 Normal pH in the vagina is 3.8-4.2, pH>4.5 is most sensitive to the diagnosis of bacterial vaginosis, but low specificity, semen in the vagina, cervical mucus, menstrual blood and trichomoniasis Inflammation, etc. can increase the pH of vaginal secretions.

3. Lactobacillus 1 to 5/HP in the secretion, and Gram-negative and Gram-positive bacilli were observed.

4. The vaginal secretion Gram staining finds the clue cells, that is, the surface of the vaginal squamous epithelial cells is attached with a large number of Brevibacterium or Cocci (Gardnerella, B. mobilis, etc.), so that the cells are spotted, granular appearance, cells The edges are blurred and jagged, when the clue cells account for more than 20% and the specificity is above 90%.

5. Compared with clinical criteria, cervical smear diagnosis, cervical smear diagnosis of bacterial vaginosis sensitivity, specificity and positive predictive value is relatively low, the sensitivity and specificity are 85% and 95%.

6. Microbial culture In healthy women, the positive rate of Gardnerella vaginalis culture is more than 60%, that is, the semi-quantitative method is used to detect densely grown colonies, in the population with low prevalence of bacterial vaginosis, according to High concentrations of Gardnerella vaginalis can predict 41% to 49% of symptomatic bacterial vaginosis. In the absence of other relevant information, vaginal Gardnerella culture can not be used for the diagnosis of bacterial vaginosis.

Diagnosis and identification of bacterial vaginosis

Clinical diagnostic criteria for bacterial vaginosis: 3 of the following 4 items can be diagnosed. It is generally believed that clue cells are positive for the diagnosis of BV.

1. Uniform, thin, white vaginal secretions.

2. Vaginal pH > 4.5 (pH is usually 4.7 ~ 5.7, mostly 5.0 ~ 5.5).

3. Amine odor test (whiff test) is positive.

4. The clue cell is positive. In severe cases, the clue cells can reach more than 20%, but almost no white blood cells.

In addition, reference may be made to the diagnostic criteria for Gram staining, Lactobacillus is a Gram-positive large bacillus, often arranged in a chain; Gardnerella is a Gram-negative or positive bacillus; Actinobacillus is a Gram-staining variation, curved, Arc-shaped small bacillus; Prevo-bacteria is Gram-negative bacilli, Gram staining standard is Lactobacillus 5 in each high power field, two or more other morphological bacteria (Gram-negative bacillus) , Arc bacillus or Gram-positive cocci) 6.

Bacterial vaginosis is a disorder of normal flora. The qualitative culture of bacteria is of little significance in the diagnosis. At present, there is a kit for bacterial vaginosis for clinical application. This disease should be differentiated from other vaginitis.

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