Pelvic inflammatory disease is an infectious process involving a woman’s upper genital tract. While the infection may be limited to the uterus, fallopian tubes, and/or ovaries, it may also become extensive and involve the neighboring pelvic organs.

Pelvic inflammatory disease (PID) is the most frequent gynecologic cause of emergency department visits, approaching 350,000 per year.¹ Complications of untreated PID are devastating and include ectopic pregnancy, infertility, and chronic pelvic pain.

Therefore, it is necessary for emergency physicians to diagnose and initiate appropriate antibiotic therapy in patients with PID in order to achieve optimal patient outcomes.

Pathogenesis

PID affects the female upper genital tract, with infection leading to endometritis, salpingitis, oophritis, pelvic peritonitis, and perihepatits.²

The dominant organism in a healthy woman’s vaginal flora is Lactobacillus acidophilus, though species of streptococci, staphylococci, and enterobacteriaceae are also present.³

While the endocervical canal typically functions as a barrier between the potentially pathogenic vaginal bacteria and the sterile female upper reproductive tract, PID results from a disruption of both the vaginal flora and the endocervical canal.

Risk factors for the development of PID include a prior episode of PID,⁴ a high number of sexual partners,⁵ use of nonbarrier contraception,⁶ and earlier age at first intercourse.⁷

Microbiology

Epidemiologic studies suggest that sexually transmitted diseases are the cause of community-acquired PID.

The most common initiating pathogens are Neisseria gonorrhoeae and Chlamydia trachomatis, although a specific inciting organism is not determined in approximately 20% of PID cases.⁸

N. gonorrhoeae was the first identified cause of PID and currently accounts for approximately 40% of PID cases overall, though there is considerable geographic variance.⁹ C. trachomatis was first recognized as an organism responsible for PID in the mid-1970s and is identified in 50% of cases.¹⁰

While the vast majority of gonorrheal and chlamydial infections are asymptomatic, it is estimated that approximately 15% of cervical infections from these organisms ultimately result in PID.¹¹