Definition of Pelvic inflammatory disease (PID)

Reviewed on 6/3/2021

Pelvic inflammatory disease (PID): Ascending infection of the female upper genital tract (the female structures above the cervix). PID is the most common and serious complication of sexually transmitted diseases (STDs), aside from AIDS, among women.

The signs and symptoms of PID include fever, foul-smelling vaginal discharge, extreme pain, including pain during intercourse, and vaginal bleeding. PID can scar the fallopian tubes, ovaries, and related structures and lead to ectopic pregnancies, infertility, chronic pelvic pain, and other serious consequences.

The infectious microorganisms in PID migrate upward from the urethra and cervix into the upper genital tract. Many different organisms can cause PID, but most cases are associated with gonorrhea and genital chlamydial infections, two very common STDs. The gonococcus (Neisseria gonorrhea), which causes gonorrhea, probably travels up into the fallopian tubes, where it causes sloughing (casting off) of some cells and invades others. It multiplies within and beneath these cells. The infection then spreads to other organs, resulting in more inflammation and scarring. The presence of a cervical mucus plug normally helps prevent the spread of microorganisms to the upper genital tract, but it is less effective during ovulation and menses. The gonococcus may gain access more easily during menses, if menstrual blood flows backward from the uterus into the fallopian tubes, carrying the organisms with it. This may explain why symptoms of PID caused by gonorrhea often begin immediately after menstruation as opposed to any other time during the menstrual cycle.

Women with STDs are at greater risk of developing PID. A prior episode of PID increases the risk because the body's defenses are often damaged during the initial bout of upper genital tract infection. Sexually active teenagers are more likely to develop PID than are older women. The more sexual partners a woman has, the greater is her risk of developing PID. Women who douche once or twice a month may also be more likely to have PID. Douching may push the microorganisms up into the upper genital tract and it may also ease the discharge, masking the infection, so the woman delays seeking health care.

The diagnosis of PID can be difficult to make. If symptoms such as lower abdominal pain are present, a physical exam may be done to determine its location, check for abnormal vaginal or cervical discharge and for evidence of cervical chlamydial infection or gonorrhea. Other tests, such as a sonogram, endometrial biopsy, or laparoscopy may be used to distinguish between PID and other serious problems that may mimic PID.

Because cultures of specimens from the upper genital tract are difficult to obtain and because multiple organisms may be responsible for an episode of PID, the treatment is to prescribe at least two antibiotics that are effective against a wide range of infectious agents. The symptoms may go away before the infection is cured. Even if symptoms do go away, the woman should finish taking all of the medicine. Women should be re-evaluated by their physicians two to three days after treatment is begun to be sure the antibiotics are working to cure the infection.

About a quarter of women with suspected PID must be hospitalized. This may be necessary if the patient is severely ill; if she cannot take oral medication and needs intravenous antibiotics; if she is pregnant or is an adolescent; if the diagnosis is uncertain and may include an abdominal emergency such as appendicitis; or if she has HIV.

The sexual partners of women with PID often have no symptoms, although they may be infected. They should therefore be treated even if they do not have symptoms to prevent reinfection and another bout of PID. If used correctly and consistently, latex condoms prevent transmission of gonorrhea and partially protect against chlamydial infection.


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