The incidence of acute PID has risen to an estimated 1,000,000 cases per year in the United States. Pelvic inflammatory disease is defined as the acute clinical syndrome attributed to the ascending spread of microorganisms from the vagina and endocervix to the endometrium, fallopian tubes, and contiguous structures. Several risk factors for PID can be identified. Previous PID damages endothelial resistance and predisposes to recurrence. Women with multiple sex partners have a relative risk factor of 4.6, and IUD users have a relative risk factor of 3.5.
Young patients are more likely to have multiple sex partners and less immunity.
Birth control pills provide some protection against salpingitis, probably because the user experiences changes in the cervical mucous and a lighter menstrual flow. Anaerobic bacteria are the most frequent tubal isolates, with peptococcus and peptostreptococcus being the most frequent. Because chlamydia is an obligatory intracellular parasite, chlamydia seems to be associated with a more indolent, less acute, less severe clinical picture of PID, with more potential for permanent tubal damage. Chlamydia may play a more important role in infertility caused by tubal obstruction. Hugh- Curtis syndrome, a clinical picture of perihepatitis and right upper quadrant pain, also has been associated with chlamydia as well as gonococcus.