Pelvic inflammatory disease (PID) usually results from an untreated sexually transmitted infection (STI). The two most common organisms associated with PID are Chlamydia trachomatis (chlamydia) and Neisseria gonorrhoeae (gonorrhea) introduced into the genital tract during sexual intercourse. However, organisms that commonly reside in the lower genital tract can also cause pelvic inflammatory disease.
Both C. trachomatis and N. gonorrhoeae are bacteria that cause infection of the columnar epithelial cells of mucosal membranes: in men, infection involves the urethra (urethritis), and in women, infection involves the endocervix (cervicitis). Gonorrhea may also involve rectal mucosa, the throat and the conjunctiva.
The World Health Organization (WHO) estimate that more than 340 million curable cases of sexually transmitted infections (STIs) occur each year, and as many as 40% of women with endocervical gonorrhea and/or chlamydia may develop pelvic inflammatory disease. Chlamydia and gonorrhea are common STDs that, if left untreated, are more likely to cause PID.
How Pelvic Inflammatory Disease Occurs:
Pelvic Inflammatory Disease occurs when organisms ascend from the lower genital tract (vagina and cervix) to infect the upper genital tract, involving the:
- endometrium , the mucous membrane that lines the uterus (endometriosis);
- fallopian tubes extending from the uterus towards the ovaries allowing passage of eggs and sperm (salpingitis);
- and/or pelvic peritoneal cavity (pelvic peritonitis).
Passage of organisms to the upper genital tract occurs through the cervix, the opening to the uterus.
The inflammatory response to PID may result in scarring and blockage of the fallopian tubes, which can lead to infertility and/or ectopic pregnancy. Scarring of the fallopian tubes may prevent eggs from reaching the uterus, and/or prevent sperm cells from reaching eggs. One in eight women with PID becomes infertile–the risk is higher with repeated episodes. Scarred fallopian tubes may also result in growth of a fertilized egg within the fallopian tube (ectopic pregnancy) rather than the uterus, leading to rupture of the fallopian tube, internal bleeding, and possibly death.
The Centers for Disease Control and Prevention (CDC) estimate more than 1 million annual cases in the U.S. alone. Of these more than 100,000 women become infertile. In addition, many ectopic pregnancies are a result of PID, and more than 150 women die each year from PID or its complications. A first episode of PID increases the risk of subsequent episodes due to damage that occurred during initial infection.
Early treatment of PID can help prevent complications, but will not reverse damage that has already occurred. If left untreated, more serious infection may occur: abscess formation, chronic pelvic pain, pelvic peritonitis (infection of the pelvic abdominal cavity) or infection that also involves the liver (perihepatitis), a condition known as Fitz-Hugh-Curtis syndrome.
Further reading on pelvic inflammatory disease:
PID: Risk Factors and Prevention
Sexually Transmitted Infections
