Pelvic Inflammatory Disease

Description

• Pelvic inflammatory disease (PID) is an infectious and inflammatory disorder of the upper female genital tract, including the uterus, fallopian tubes, ovaries, and adjacent pelvic structures. PID is most commonly an ascending polymicrobial infection acquired from sexually transmitted organisms (1).
• Salpingitis is the most clinically critical diagnostic component due to its consequences for future fertility.
• Mild to moderate PID is infection and inflammation in the absence of a tubo-ovarian abscess (TOA). Severe disease is defined as severe systemic symptoms OR the presence of a TOA (2).
• Diagnosis may be challenging due to nonstandardized definitions and guidelines, lack of a single definitive diagnostic test, and variation in signs and symptoms. Many patients with PID have subtle or nonspecific symptoms (3).

Epidemiology

Predominant age: 15 to 29 years

Incidence
PID is the most common gynecologic reason for admission in the United States accounting for 18 per 10,000 recorded hospital discharges (2).

Prevalence
The estimated prevalence of self-reported lifetime PID is 4.4% in sexually active cisgender women ages 18 to 44 years.

• Lifetime prevalence has decreased steadily since 1995 (4).
• Among those with no history of prior STI, lifetime prevalence higher in black versus white women (6% vs. 2.7%). Among patients with a prior STI, lifetime prevalence was similar across race (10% vs. 10.3%). This disparity suggests black patients might be more likely to have had an undiagnosed STI or not received care for a symptomatic infection, subsequently developing PID (4).

Etiology and Pathophysiology

Multiple organisms cause PID. Most cases begin with cervicitis and progress to polymicrobial infection. <50% of women with acute PID test positive test for a microbe.

• Mixed infections are common. Chlamydia trachomatis, Neisseria gonorrhoeae, genital tract mycoplasmas (particularly Mycoplasma genitalium), aerobic and anaerobic (Bacteroides fragilis), and vaginal microbes (e.g., Prevotella, peptostreptococci, Gardnerella vaginalis, Escherichia coli, Haemophilus influenzae) are common flora (1),(5),(6).
• Many nongonococcal, nonchlamydial microorganisms recovered from the upper genital tract in acute PID are associated with bacterial vaginosis.
• Possible mechanisms for ascent from the lower genital tract include (i) travel from cervix to endometrium to salpinx to peritoneal cavity; (ii) lymphatic spread via infection of the parametrium (from an IUD); and (iii) hematogenous route, although this is rare.
• Of cases, 75% occur within 7 days of menses, when cervical mucus favors ascent of organisms.

Risk Factors

• Sexually active and age <25 years
• First sexual activity at younger age (<15 years)
• New/multiple sexual partners
• Inconsistent condom use
• Gynecologic procedures that break the cervical barrier such as endometrial biopsy, curettage, hysterosalpingography, hysteroscopy, in vitro fertilization, and insertion of IUD in the last 6 weeks
• Other factors associated with PID:
  • Certain contraceptive methods, such as oral contraceptive pills and spermicidal creams, disrupt vaginal pH/microbiome and increase risk for STIs
  • Previous history of PID; 20–25% will have a recurrence.
  • Cervical ectopy
  • History of C. trachomatis; 10–40% will develop PID.
  • History of gonococcal cervicitis; 10–20% will develop PID.

General Prevention

• Educational programs about safe sex practices such as barrier contraceptives, especially condoms
• The U.S. Preventive Services Task Force recommends annual screening for chlamydia in all sexually active women <25 years and in those ≥25 years at increased risk (new sex partner/multiple sex partners). Moderate-quality evidence suggests that chlamydia screening reduces cases of PID (3)[A].
• Routine STI screening in pregnancy
• Early medical care with occurrence of genital lesions or abnormal discharge

Commonly Associated Conditions

• In a patient with an IUD and a pelvic abscess, suspect Actinomyces infection requiring penicillin treatment.
• Rupture of an adnexal abscess is rare but life-threatening. Early surgical exploration is mandatory (5).
• Chlamydial or gonococcal perihepatitis, called Fitz-Hugh-Curtis (FHC) syndrome, may occur with PID. FHC syndrome is characterized by severe pleuritic right upper quadrant pain and complicates 10% of PID cases.
• Plasma cell endometritis in women with PID: seen in majority of women with PID; density of plasma cell infiltration correlates to severity of symptoms (5).