Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Pelvic inflammatory disease (PID) is a general term for infection of the upper female genital tract, including the uterus, Fallopian tubes, and ovaries.
PID usually results from ascending infection from the cervix. 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.
- The exact prevalence of PID is unknown as it is under-diagnosed and it is also often asymptomatic.
- The rate of definite PID diagnosis in primary care is around 280/100,000 person-years.
- PID most commonly occurs in women aged 20-29 years.
- 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.
- Genital chlamydial infection is currently the most common sexually transmitted infection diagnosed in genitourinary medicine (GUM) clinics in the UK.
- The incidence of gonorrhoea is increasing and therefore becoming a more common cause of PID.
- Other organisms implicated in PID include those commonly associated with bacterial vaginosis - eg, Gardnerella vaginalis, Mycoplasma hominis, Mobiluncus spp. and other anaerobes. Actinomycetes are part of the normal vaginal flora and a rare cause of PID.
- Risk factors for acquiring sexually transmitted infections - eg, young age, new sexual partner, multiple sexual partners, lack of barrier contraception, lower socio-economic group.
- There may be an increased risk in those women who have had an intrauterine contraceptive device (IUCD) inserted in the previous 20 days.
- Termination of pregnancy.
Diagnosis of acute PID made only on clinical signs and positive swab results is 65-90% as accurate when compared to laparoscopic diagnosis. Many episodes of PID go unrecognised, as women often have absent, mild, or atypical symptoms.
There is no combination of symptoms and signs to make a clinical diagnosis of PID so it is very important to have a high index of suspicion for PID.
The following features are suggestive of PID:
- Bilateral lower abdominal pain.
- Deep dyspareunia.
- Abnormal vaginal bleeding (postcoital, intermenstrual or menorrhagia).
- Vaginal or cervical discharge that is purulent.
- 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).
Other symptoms and signs include nausea or vomiting, urinary symptoms, proctitis and an adnexal mass.
- Other causes of abdominal pain - eg, appendicitis (nausea and vomiting are seen more often than PID), ectopic pregnancy.
- Other causes of abnormal vaginal bleeding.
- Other causes of vaginal discharge - eg, foreign body.
- Other causes of dyspareunia - eg, endometriosis.
- 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; however, a negative result does not exclude PID.
- Endocervical swabs for C. trachomatis and N. gonorrhoeae, using nucleic acid amplification tests where available, are recommended in all patients with suspected PID.
- An elevated ESR or CRP may also support a diagnosis of PID; however, these are nonspecific tests.
- 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 obviously not appropriate in routine clinical practice.
- Urinalysis and urine culture to exclude urinary tract infection.
- Ultrasound scans may be useful in excluding other conditions.
- Mild or moderate disease can be managed in primary care or outpatients, whereas clinically severe disease requires hospital admission for intravenous (IV) antibiotics.
- 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.
- Consider referral to a GUM clinic, for a full sexually transmitted infection screen (HIV, etc), contact tracing and treatment of sexual partners.
- Do not delay antibiotic treatment while waiting for the results of tests if PID is clinically suspected.
- 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.
- The choice of an appropriate treatment regimen may be influenced by local guidelines, cost, patient preference and severity of disease.
- Broad-spectrum antibiotic treatment to cover C. trachomatis, N. gonorrhoeae and anaerobic infection is recommended.
- 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. An alternative regime is oral ofloxacin 400 mg twice daily and oral metronidazole 400 mg twice daily for 14 days. 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.
- The current treatment recommendation for severely ill patients is:
- IV therapy is recommended for patients with more severe clinical disease - eg, pyrexia above 38°C, clinical signs of tubo-ovarian abscess, signs of pelvic peritonitis or pregnancy.
- Initial treatment is 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 empirical 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.
- IV therapy should be continued for 24 hours after signs of clinical improvement.
- In those who fail to respond to treatment, laparoscopy is essential to confirm the diagnosis or to make an alternative diagnosis.
Management of sexual partners
- Patients should be advised to avoid unprotected intercourse until they and their partner(s) have completed treatment and follow-up.
- 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.
- As many cases of PID are not associated with gonorrhoea or chlamydia, broad-spectrum empirical therapy should also be offered to male partners - eg, azithromycin 1 g single dose.
Admission to secondary care (for IV antibiotics and/or further investigation) should be considered in the following situations:
- Diagnostic uncertainty - eg, where appendicitis or ectopic pregnancy cannot be excluded.
- Severe symptoms or signs.
- Deteriorating clinical condition.
- Clinical failure with oral treatment, ie failure to show substantial improvement within three days.
- Inability to tolerate oral treatment - eg, due to nausea and vomiting.
- Presence of a tubo-ovarian abscess.
- Immunodeficiency - eg, HIV infection, immunosuppression therapy.
Studies have shown that delaying treatment by as little as two or three days increases the risk of infertility.Prompt treatment for cases of suspected PID is therefore very important. Complications include:
- 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 Curtis syndrome): causes right upper quadrant pain.
- 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.
- Use of barrier contraception significantly reduces the risk of PID.
- Limited evidence suggests that screening for chlamydia and treating identified infection prior to IUCD insertion reduce the risk of PID. Routine prophylactic antibiotics prior to IUCD insertion are not recommended.
- The English National Chlamydia Screening Programme (NCSP) recommends that all sexually active men and women under the age of 25 be tested for chlamydia annually or on change of sexual partner.
- Highly sensitive and specific tests - nucleic acid amplification tests (NAATs) - for chlamydia are widely available, and used for all chlamydia tests performed through this screening programme. These tests can be performed on non-invasive samples (urine in men, self-taken vulvovaginal swabs or urine for women).
- Testing for gonorrhoea is recommended within specialist sexual health clinics targeting higher-risk populations or where clinically indicated.However, there is no evidence to support widespread opportunistic screening for gonorrhoea in community-based settings, and the evidence for selected screening in UK community-based settings is sparse.
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