Pelvic inflammatory disease (PID) is a general term for infection of the upper genital tract, including the uterus, Fallopian tubes, and ovaries.

PID usually results from ascending infection from the cervix.¹ It is a common and serious complication of some sexually transmitted diseases, especially chlamydia and gonorrhoea. It can damage the Fallopian tubes and tissues in and near the uterus and ovaries. Untreated PID can lead to serious complications, including infertility, ectopic pregnancy, abscess formation and chronic pelvic pain.

Epidemiology

• Pelvic infections are often polymicrobial. PID can be caused by genital mycoplasmas, endogenous vaginal flora (anaerobic and aerobic bacteria), aerobic streptococci, Mycobacterium tuberculosis, and sexually transmitted infections such as Chlamydia trachomatis or Neisseria gonorrhoeae.²
• Genital chlamydial infection is currently the most common sexually transmitted infection diagnosed in genitourinary medicine (GUM) clinics in the United Kingdom.^3,4
• The incidence of gonorrhoea is increasing and therefore becoming a more common cause of PID.⁵
• Other organisms implicated in PID include those commonly associated with bacterial vaginosis, e.g. Gardnerella vaginalis, Mycoplasma hominis, Mobiluncus spp. and other anaerobes.¹ Actinomycetes are part of the normal vaginal flora and a rare cause of PID.

Risk factors

• Risk factors for acquiring sexually transmitted infections, e.g. young age, new sexual partner, multiple sexual partners, lack of barrier contraception, lower socio-economic group.²
• Insertion of intrauterine contraceptive device (IUCD) - for the first 3-4 weeks after insertion.⁶
• Termination of pregnancy⁷

Presentation

Diagnosis of acute PID made only on clinical signs and positive swab results is 65-90% as accurate when compared to laparoscopic diagnosis.⁸ Many episodes of PID go unrecognised, as women often have absent, mild, or atypical symptoms.

Symptoms

• The following features are suggestive of PID:¹
• Bilateral lower abdominal pain.
• Deep dyspareunia.
• Abnormal vaginal bleeding (postcoital, intermenstrual or menorrhagia).
• Vaginal or cervical discharge that is purulent.

Signs

• Lower abdominal tenderness (usually bilateral).
• Mucopurulent cervical discharge and cervicitis seen on speculum examination.
• Cervical motion tenderness and adnexal tenderness on bimanual vaginal examination.
• Fever above 38°C (but may be apyrexial).

Differential diagnosis

• Other causes of abdominal pain, e.g. appendicitis (nausea and vomiting are seen more often than PID), ectopic pregnancy.
• Other causes of abnormal vaginal bleeding.
• Other causes of vaginal discharge, e.g. foreign body.
• Other causes of dyspareunia, e.g. endometriosis.

Investigations

• Pregnancy test (pregnant women with PID should be admitted; ectopic pregnancy may be confused with PID).
• Cervical swabs for chlamydia and gonorrhoea: a positive result supports the diagnosis of PID, but a negative result does not exclude PID.
• An elevated ESR or CRP also supports a diagnosis of PID.
• Endometrial biopsy and ultrasound scanning may also be helpful.
• Laparoscopy with direct visualisation of the Fallopian tubes is the best single diagnostic test, but is an invasive procedure and therefore not appropriate in routine clinical practice.¹
• Urinalysis and urine culture: to exclude urinary tract infection.

Management

• Provide adequate pain relief.
• The evidence for whether an IUCD should be left in situ or removed is limited. Removal of the IUCD may be associated with better short-term clinical outcomes. The decision to remove the IUCD needs to be balanced against the risk of pregnancy in those who have had otherwise unprotected intercourse in the preceding seven days.⁸
• Consider referral to a GUM clinic, for a full sexually transmitted infection screen (HIV, etc.), contact tracing and treatment of sexual partners.

Antibiotic treatment

• The current outpatient treatment recommendation is ceftriaxone 500 mg as a single intramuscular (IM) dose, followed by doxycycline 100 mg orally twice-daily and metronidazole 400 mg twice-daily, for 14 days.⁸
• Do not delay antibiotic treatment while waiting for the results of tests if PID is clinically suspected. It is likely that delayed treatment increases the risk of long-term complications, such as ectopic pregnancy, infertility and pelvic pain. Negative swabs do not exclude PID and therefore should not influence the decision to treat. Emphasise the importance of completing the course of antibiotics to reduce the risk of long-term complications.
• Broad-spectrum antibiotic treatment to cover C. trachomatis, N. gonorrhoeae and anaerobic infection is recommended.
• Other recommended regimes include:⁸
  • Outpatient regimens:
    • Ofloxacin 400 mg orally twice-daily plus oral metronidazole 400 mg twice-daily, for 14 days.⁹ This is not recommended if the woman is at high risk of gonococcal PID because of increasing quinolone resistance of gonorrhoea. Levofloxacin may be used as a once-daily, convenient alternative to ofloxacin.
  • Severely ill patients:
    • Intravenous (IV) therapy is recommended for patients with more severe clinical disease, e.g. pyrexia above 38°C, clinical signs of tubo-ovarian abscess, signs of pelvic peritonitis or pregnancy.⁸
    • Initial treatment with doxycycline, single-dose IV ceftriaxone and IV metronidazole, then change to oral doxycycline and metronidazole to complete 14 days of treatment.
    • There is no evidence-based recommendation for treatment in pregnancy, but an empiric regimen might include IM ceftriaxone plus oral or IV erythromycin, with the possible addition of oral or IV metronidazole 500 mg three times daily in clinically severe disease. Any risk of this regimen is justified on the basis of need to provide therapy and low risk to the fetus.⁸
    • IV therapy should be continued for 24 hours after signs of clinical improvement.

Management of sexual partners¹

• Although most infected male partners have no symptoms, infection rates of 26-36% for C. trachomatis have been reported among partners.¹⁰
• Patients should be advised to avoid unprotected intercourse until they, and their partner(s) have completed treatment and follow-up.⁸
• Screen for other sexually transmitted infections, ideally at a GUM clinic. All sexual partners within the previous six months (or the most recent sexual partner if there have been no sexual contacts within the previous six months) should be notified and offered screening for sexually transmitted infections.
• Sexual partners should be treated for chlamydial infection even if this is not identified on testing.
• Treatment for gonorrhoea only needs to be offered if N. gonorrhoeae is identified in the woman with PID or in her partner.
• Empirical treatment for chlamydial infection and gonorrhoea should be given to partners who are unwilling to be screened.

Referral

Admission to secondary care (for IV antibiotics and/or further investigation) should be considered in the following situations:^1,8

• Diagnostic uncertainty, e.g. where appendicitis or ectopic pregnancy cannot be excluded.
• Severe symptoms or signs.
• Deteriorating clinical condition.
• Clinical failure with oral treatment, i.e. failure to show substantial improvement within three days.
• Inability to tolerate oral treatment, e.g. due to nausea and vomiting.
• Presence of a tubo-ovarian abscess.
• Pregnancy.
• Immunodeficiency, e.g. HIV infection, immunosuppression therapy.

Complications

• Infertility: the risk of infertility following PID is related to the number of episodes of PID and their severity.
• Ectopic pregnancy.
• Chronic pelvic pain.
• Perihepatitis (Fitz-Hugh and Curtis syndrome): causes right upper quadrant pain. Occurs in up to 10-20% of women with PID.⁸
• Tubo-ovarian abscess.
• Reiter's syndrome (reactive arthritis).
• In pregnancy: PID is associated with an increase in preterm delivery, and maternal and fetal morbidity.
• Neonatal: perinatal transmission of C. trachomatis or N. gonorrhoeae can cause ophthalmia neonatorum. Chlamydial pneumonitis may also occur.

Prevention

• Limited evidence suggests that screening for chlamydia and treating identified infection prior to IUCD insertion reduces the risk of PID.¹ Routine prophylactic antibiotics prior to IUCD insertion are not recommended.
• It has been recommended that testing for chlamydia be offered to women at increased risk of sexually transmitted infections and to all sexually active women aged under 25 years.

Document references

1. Pelvic inflammatory disease, Prodigy (Aug 2009)
2. Simms I, Stephenson JM; Pelvic inflammatory disease epidemiology: what do we know and what do we need to know? Sex Transm Infect. 2000 Apr;76(2):80
3. Chlamydia (Chlamydia trachomatis), Health Protection Agency
4. Chlamydia - uncomplicated genital, Prodigy (May 2009)
5. Gonorrhoea (Neisseria gonorrhoeae), Health Protection Agency; general information
6. Meirik O; Intrauterine devices - upper and lower genital tract infections. Contraception. 2007 Jun;75(6 Suppl):S41-7. Epub 2007 Feb 16. [abstract]
7. Achilles SL, Reeves MF; Prevention of infection after induced abortion: release date October 2010: SFP Contraception. 2011 Apr;83(4):295-309. Epub 2011 Feb 12. [abstract]
8. Management of PID, British Association for Sexual Health and HIV (2011)
9. Management of Infection - Guidance for Primary Care, Health Protection Agency, various dates; (including diagnosis - quick reference guides)
10. McCathie RP, Carlin EM; Does partner notification of men with asymptomatic non-gonococcal non-chlamydial Int J STD AIDS. 2007 Sep;18(9):606-9. [abstract]

Internet and further reading

• Sexually transmitted and other reproductive tract infections: A guide to essential practice, World Health Organization
• Chlamydia - uncomplicated genital, Prodigy (May 2009)
• Management of sexually transmitted infections and related conditions in children and young people, British Association for Sexual Health and HIV (2010)