Pelvic inflammatory disease. A brief overview.

Most pelvic inflammatory disease (PID) is caused by the ascent of sexually transmitted disease pathogens from the endocervix. In fact, PID remains the most common serious complication of infection from sexually transmitted bacterial pathogens. PID also may be caused by normal vaginal micro-organisms (such as those associated with bacterial vaginosis) that have overgrown in the vagina. PID has been linked to the occurrence of long-term sequelae, most commonly and most importantly infertility and ectopic pregnancy. In many patients PID may remain undiagnosed and asymptomatic, and may not become evident until such long-term consequences become manifest. We briefly review the epidemiology of PID including case definitions, the prevalence of the problem, and causal pathways and associated risk factors. Risk factors for both PID and its sequelae are discussed in relation to the mechanism of ascent of associated etiologic agents from the lower to the upper genital tract.