STI-associated syndromes guide: Pelvic inflammatory disease

On this page:

• Public health importance
• Common STI-associated etiology
• Clinical manifestations
• Diagnostic testing
• Empiric treatment and management
• Follow-up
• Reporting and partner notification
• References

Public health importance

PID is the most common infectious cause of lower abdominal pain in females^{Footnote 1}. Up to two-thirds of cases may not be recognized.

In Canada, there are approximately 100,000 cases of symptomatic PID diagnosed annually. In addition, it is estimated that 10%-15% of reproductive-aged females have had at least one episode of PID^{Footnote 2}.

Long-term sequelae of PID include infertility, ectopic pregnancy and chronic pelvic pain. The likelihood of developing these long-term sequelae is related to the number of PID episodes the person has experienced^{Footnote 3}.

Common STI-associated etiology

PID can be a complicated polymicrobial infection. Etiologic agents associated with PID may include sexually transmitted infections (STIs) and endogenous anaerobic and facultative (aerobic) bacteria.

In most cases, the specific microbial etiology of PID is unknown and no specific organism is identified. Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are the most identified STIs in cases of PID. CT, GC and Mycoplasma genitalium account for an estimated 30%-40% of cases^{Footnote 4}.

Approximately 15% of persons with endocervical GC or CT develop PID ^{Footnote 5Footnote 6Footnote 7}.

Other possible infectious causes: Trichomonas vaginalis, Gardnerella vaginalis, Mycoplasma hominis, Ureaplasma urealyticum, Bacteroides spp., Peptostreptococcus spp., Prevotella spp., Streptococcus spp., Escherichia coli and Haemophilus influenza^{Footnote 8}.

Clinical manifestations

Symptoms and signs of PID include:

• Adnexal tenderness
• Cervical motion tenderness
• Fever > 38.3°C
• Abdominal tenderness

GC-associated PID tends to be clinically more severe than CT-associated PID^{Footnote 4Footnote 9}.

Diagnostic testing

Abdominal and pelvic examination is indicated for individuals presenting with symptoms of PID, including:

• Speculum and bimanual exam
• Inspection of external genital area, vagina and cervix

Consider and rule out an ectopic pregnancy.

Recommended testing:

• Pregnancy test
• Endocervical swab for nucleic acid amplification tests (NAAT) for CT and GC, plus culture for GC (where available)
  • Vaginal swabs or first-void urine are also appropriate specimens for NAAT
  • Vaginal swabs for culture to detect GC are not recommended^{Footnote 10}
• Vaginal swabs for bacterial vaginosis and Trichomonas vaginalis detection (consult your local laboratory for availability)
• Pelvic ultrasound, particularly if tubo-ovarian abscess or ectopic pregnancy are suspected

Other tests that may be helpful in the diagnosis of acute PID include: complete blood count, erythrocyte sedimentation rate, C-reactive protein, endometrial biopsy, transvaginal sonography and laparoscopy.

Minimum diagnostic criteria:

• Adnexal tenderness
• Cervical motion tenderness
• Lower abdominal tenderness

Additional diagnostic criteria:

• Oral temperature >38.3°C
• Presence of white blood cells in vaginal secretions on wet mount or Gram stain
• Elevated erythrocyte sedimentation rate or elevated C-reactive protein
• Laboratory documentation of cervical infection with GC, CT or M. genitalium

Definitive diagnostic criteria:

• Endometrial biopsy with histopathologic evidence of endometritis^{Footnote 11}
• Transvaginal sonography or other imaging techniques showing thickened fluid-filled tubes, with or without free pelvic fluid or tubo-ovarian complex
• Gold standard: Laparoscopy demonstrating abnormalities consistent with PID, such as fallopian tube erythema or mucopurulent exudates

Empiric treatment and management

Early diagnosis and treatment are crucial to maintain fertility. Due to the polymicrobial nature of the infection, empiric treatment regimens include broad-spectrum coverage for the most likely etiologic agents such as STI, facultative bacteria and streptococci^{Footnote 12}.

Notes:

• Consider adding metronidazole to provide anaerobic coverage for people who are acutely ill (fever, chills and toxicity) or who have bacterial vaginosis^{Footnote 14}.
• Quinolones are effective in treating acute PID that is not caused by quinolone-resistant GC^{Footnote 15Footnote 16Footnote 17}.
• Consult an experienced colleague when there are contraindications to the recommended treatments.

The management of people with PID is not adequate unless sexual partners are also evaluated and treated.

Hospitalization is indicated in the following circumstances:

• Surgical emergencies such as appendicitis or ectopic pregnancy or tubo-ovarian abscess cannot be ruled out
• Pregnancy: Although PID in pregnancy is not common especially after the first trimester, there is an increased risk of adverse outcomes for both the person and the pregnancy
• Severe pain, illness, nausea, vomiting or high fever
• No clinical response to outpatient treatment regimen 2-3 days after initiation^{Footnote 18}
• Inability to follow or tolerate oral treatment regimen
• Immunocompromised

PID is not an indication for intrauterine device (IUD) removal^{Footnote 19}. If IUD removal is planned, delay removal until at least two doses of antibiotics have been administered.

Follow-up

Evaluate response to treatment after 2-3 days^{Footnote 18}. If there is no clinical improvement, consider consulting an experienced colleague. Hospitalization may be necessary for further investigation, parenteral therapy and observation. Consider other differential or mixed diagnoses and a laparoscopy.

The need for test of cure (TOC) depends on which pathogen is confirmed by laboratory testing. Refer to the etiology-specific guide.

In persons with persistent or recurrent PID, consider NAAT testing for M. genitalium, including antibiotic susceptibility (where available). If testing is not available, consider empiric treatment for M. genitalium. Refer to Mycoplasma genitalium guide.

Reporting and partner notification

When treatment is indicated for an STI: notify, evaluate, test and treat (as appropriate) sexual partners. Refer to the etiology-specific guide(s) for guidance on reporting and partner notification.