Bacterial vaginosis overview

# Overview
Bacterial vaginosis (BV) is a syndrome that results from an imbalance in the different types of bacteria in the vagina (also known as vaginal "flora").
Lactobacilli play an important role in maintaining the female genital tract health by keeping the vagina's pH at normal levels.
When the pH levels of the vagina become unbalanced, certain microorganisms may overtake the normal flora, which can cause a low-grade infection that often produces an abnormal vaginal discharge.
Bacterial vaginosis must be differentiated from other diseases that cause purulent, malodorous, thin vaginal discharge with elevated vaginal pH (<4.5), such as trichomoniasis, atrophic vaginitis, and desquamative inflammatory vaginitis. Additionally, bacterial vaginosis must also be differentiated from such other conditions as vaginal candidiasis, vaginitis, and cervicitis.
Bacterial vaginosis is the most common cause of vaginal symptoms among women; it is not clear what role sexual activity plays in the development of BV. The prevalence of BV in the United States is estimated to be 21.2 million (29.2%) among women ages 1449.
Untreated BV can lead to premature delivery, postpartum infections, clinically apparent and subclinical pelvic inflammatory disease (PID), post-surgical complications (after abortion, hysterectomy, cesarean section, and other reproductive procedures), increased vulnerability to HIV infection and, sometimes, infertility.
Antimicrobial therapy is recommended for all symptomatic women and high-risk, asymptomatic pregnant women with bacterial vaginosis. Metronidazole is the drug of choice for pregnant patients.
Basic effective measures for the primary prevention of bacterial vaginosis include limiting the number of sexual partners, avoiding douching, and using condoms and estrogen-containing contraceptives while sexually active.

# Historical perspective
In 1892, Albert Doderlein first described the hypothesis that bacterial flora may be a cause of vaginal infectious conditions. In 1955, Gardner and Dukes first named Haemophilus vaginalis (Gardnerella vaginalis) as a new genus and the cause of foul-smelling, watery vaginal discharge.

# Pathophysiology
Bacterial vaginosis is a syndrome that results from an imbalance in the different types of bacteria in the vagina (also called vaginal "flora"). 
The healthy vaginal microflora is comprised mainly of Gram-positive bacilli of the genus lactobacillus.
Lactobacilli play an important role in maintaining the health of the female genital tract by keeping the vagina's pH at normal levels.
When the pH levels of the vagina become unbalanced, certain microorganisms may overtake the normal flora, causing a low-grade infection that often produces an abnormal vaginal discharge.

# Causes
Common causes of bacterial vaginosis include gardnerella vaginalis, mycoplasma hominis, ureaplasma, and anaerobes.

# Differential Diagnosis
Bacterial vaginosis must be differentiated from other diseases that cause purulent, malodorous, thin vaginal discharge with elevated vaginal pH (<4.5), such as trichomoniasis, atrophic vaginitis, and desquamative inflammatory vaginitis. Additionally, bacterial vaginosis also must be differentiated from such other conditions as vaginal candidiasis, vaginitis, and cervicitis.

# Epidemiology
Bacterial vaginosis is the most common cause of vaginal symptoms among women; it is not clear what role sexual activity plays in the development of BV. The prevalence of BV in the United States is estimated to be 21.2 million (29.2%) among women ages 1449.

# Risk Factors
Common risk factors in the development of bacterial vaginosis include sexual activity, having a new sexual partner or multiple sexual partners, being a woman who has sex with women, the presence of other sexually transmitted infections, douching, and cigarette smoking.

# Screening
General screening for bacterial vaginosis is not recommended. According to the United States Preventive Services Task Force, sufficient evidence does not exist for the recommendation of routine screening for bacterial vaginosis (BV) in asymptomatic pregnant women at high or low risk for preterm delivery for the prevention of preterm birth.

# Natural history, complications, and prognosis
Most women who present with bacterial vaginosis (BV) report no symptoms. Symptomatic patients may present with vaginal odor and white/gray vaginal discharge.
If left untreated, bacterial vaginosis may progress to more serious conditions such as salpingitis, endometritis, bacteremia, and pelvic inflammatory disease (PID).
In most cases, BV causes no complications. 
However, some complication of bacterial vaginosis may include endometritis, cervicitis, pelvic inflammatory disease (PID), bacteremia, and an increased susceptibility to other STDs.
Approximately one-third of pregnant women have bacterial vaginosis.
If left untreated in pregnant women, bacterial vaginosis may result in serious pregnancy-related complications including premature rupture of membranes, premature labor, chorioamnionitis, postpartum endometritis, and septic abortion.

# Diagnosis

## Amsel criteria
BV is a common vaginal condition characterized by at least three of the following four Amsel criteria, which include thin, gray/white vaginal discharge; malodorous, fishy discharge upon adding 10% potassium hydroxide; high vaginal pH (>4.5); and the identification of clue cells.

## History and Symptoms
It is necessary to obtain a detailed and thorough sexual history from the patient in order to diagnose BV. Specific areas of focus when obtaining a history from the patient include number and type of sexual partners (new, casual, or regular) and any previous history of STDs. 
50-75% of women with bacterial vaginosis (BV) are asymptomatic.
Common symptoms of bacterial vaginosis include thin white/gray vaginal discharge and unpleasant vaginal odor, especially after sex.

## Physical Examination
A genital examination of patients with bacterial vaginosis is usually remarkable for fishy odor from the vagina; thin, white/gray vaginal discharge; and the lack of significant vulvovaginal inflammation.

## Laboratory Findings
Bacterial vaginosis can be diagnosed through the use of clinical criteria (amsels diagnostic criteria) or gram stain. A gram stain is considered the gold standard laboratory method for diagnosing bacteria vaginosis.

## Imaging findings
No imaging findings are associated with bacterial vaginosis.

## Other diagnostic studies
Other diagnostic studies associated with diagnosis of bacterial vaginosis (BV) include the Affirm VP III test, chromogenic diagnostic test (OSOM BVBlue system), and quantitative polymerase chain reaction (PCR).

# Treatment

## Medical Therapy
Antimicrobial therapy is recommended for all symptomatic women and high-risk asymptomatic pregnant women with bacterial vaginosis. Metronidazole is the drug of choice in pregnant patients with BV.

## Primary Prevention
Basic, effective measures for the primary prevention of bacterial vaginosis include limiting one's number of sexual partners, avoiding douching, and using condoms and estrogen-containing contraceptives while sexually active.

## Secondary prevention
Effective measure for the secondary prevention of infective conjunctivitis include maintaining a vaginal pH of 4.5, bacteriotherapy, avoiding douching, and changing one's method of contraception.