Pelvic Inflammatory Disease (PID)
Pathophysiology
PID results from ascending infection where microorganisms migrate from the vagina or cervix to the fallopian tubes and other upper genital tract structures (endometrium, fallopian tubes, ovaries, peritoneum) 1, 2
Polymicrobial etiology is the rule, with most cases involving multiple organisms rather than a single pathogen 1, 3
Primary pathogens include:
Secondary pathogens from endogenous lower genital tract flora include:
Bacterial vaginosis is recognized as an antecedent condition that predisposes to polymicrobial acute PID 1
Clinical Features
Minimum Diagnostic Criteria (Must Have All Three)
Treatment should be initiated based on these minimum criteria alone in the absence of competing diagnoses 1:
Additional Routine Criteria (Increase Specificity)
- Oral temperature >38.3°C 1
- Abnormal cervical or vaginal discharge 1
- Elevated erythrocyte sedimentation rate and/or C-reactive protein 1
- Culture or non-culture evidence of cervical infection with N. gonorrhoeae or C. trachomatis 1
Elaborate Criteria (More Definitive but Invasive/Expensive)
- Histopathologic evidence on endometrial biopsy 1
- Tubo-ovarian abscess on sonography 1
- Laparoscopic visualization of inflamed, purulent fallopian tubes 1, 4
Clinical Presentation Spectrum
- Many women present with minimal or atypical symptoms, and some experience "silent PID" with no recognized symptoms 1
- Clinical diagnosis has only approximately two-thirds positive predictive value when compared to laparoscopic findings 1
Investigations
Mandatory Tests for All Suspected Cases
Additional Investigations
- Pelvic ultrasonography to exclude tubo-ovarian abscess (mandatory) 5
- Pregnancy test to exclude ectopic pregnancy 1
- Complete blood count (white blood cell count may be normal, especially in HIV-infected patients) 1
- Vaginal and endocervical sampling for molecular and bacteriological analysis 5
Expected Findings
- Elevated inflammatory markers (ESR, CRP) in many but not all cases 1
- Positive cervical cultures or NAATs for N. gonorrhoeae or C. trachomatis in 5%-80% depending on pathogen and population 1
- Tubo-ovarian abscess on imaging in complicated cases 1, 5
- Endometrial biopsy showing histopathologic inflammation if performed 1
Treatment
Hospitalization Criteria
Hospitalization should be considered whenever possible and is particularly recommended when 1, 6:
- Diagnosis is uncertain 1, 6
- Surgical emergencies (appendicitis, ectopic pregnancy) cannot be excluded 1, 6
- Pelvic abscess is suspected 1, 6
- Patient is pregnant 1, 6
- Patient is an adolescent (compliance unpredictable, long-term sequelae particularly severe) 1, 6
- Severe illness precludes outpatient management 1, 6
- Patient unable to tolerate outpatient regimen 1, 6
- Patient has failed to respond to outpatient therapy 1, 6
- Clinical follow-up within 72 hours cannot be arranged 1, 6
Inpatient Treatment Regimens
Regimen A (continue at least 48 hours after clinical improvement) 6:
- Cefoxitin 2 g IV every 6 hours 6, 7
- OR Cefotetan 2 g IV every 12 hours 6
- PLUS Doxycycline 100 mg oral or IV every 12 hours 6
- After discharge, continue doxycycline 100 mg orally twice daily to complete 14 days total 6
Regimen B (continue at least 48 hours after clinical improvement) 6:
- Clindamycin 900 mg IV every 8 hours 6
- PLUS Gentamicin (loading and maintenance doses per institutional protocol) 6
- Clindamycin provides more complete anaerobic coverage than doxycycline 6
For Tubo-Ovarian Abscess 5:
Outpatient Treatment Regimens (Mild-to-Moderate PID)
- Cefoxitin 2 g IM PLUS Probenecid 1 g oral simultaneously 6
- PLUS Doxycycline 100 mg oral twice daily for 10-14 days 6
- Consider adding metronidazole for anaerobic coverage in most cases 3, 4
Alternative: Ofloxacin-based regimen 5:
- Ofloxacin + Metronidazole for 14 days 5
Critical Treatment Principles
- Broad-spectrum coverage must include N. gonorrhoeae, C. trachomatis, anaerobes, and facultative bacteria 1, 3
- Cephalosporins have NO activity against C. trachomatis; appropriate antichlamydial coverage (doxycycline or azithromycin) must always be added 8, 7
- Doxycycline is the treatment of choice for chlamydial disease 6
- Antibiotic therapy should be started early and given for adequate duration to reduce complications 4
Sex Partner Management
- Treatment of sex partners is imperative and management is inadequate without it 1
- All sex partners must be empirically treated with regimens effective against C. trachomatis and N. gonorrhoeae 1, 6
- Failure to treat partners places woman at risk for reinfection and complications 1
Monitoring
Initial Follow-up
- Clinical reassessment at 48-72 hours is mandatory 1
- If no clinical improvement at 48-72 hours, reconsider alternate diagnoses (appendicitis, endometriosis, ruptured ovarian cyst, adnexal torsion) 1
- Consider alternate or additional antimicrobial therapy if no improvement 1
Patient Education and Compliance
- Emphasize need to take all medication regardless of symptom resolution 1
- Review contraindications and potential side effects 1
- Emphasize need to avoid sexual intercourse until treatment completed 1
- Ensure sex partners referred for evaluation and treatment 1
Long-term Considerations
- After one episode of PID, risk of ectopic pregnancy increases sevenfold 1
- Infertility risk: 12% after one episode, 25% after two episodes, >50% after three or more episodes 1
- 15%-20% of women develop complications requiring surgical intervention 1
- Sequelae include chronic pelvic pain, dyspareunia, pyosalpinx, tubo-ovarian abscess, pelvic adhesions 1