Pelvic Inflammatory Disease (PID)

Essentials

• Pelvic inflammatory disease (PID) is an acute infection usually originating in the uterine cervix, which may cause endometritis, salpingitis, oophoritis, pelvic abscess, peritonitis and/or perihepatitis.
• Early diagnosis and treatment prevent late sequelae of PID:
  • infertility due to fallopian tube damage
  • ectopic pregnancy
  • chronic abdominal pain.

Epidemiology

• PID mainly occurs in sexually active women of reproductive age. The risk of PID is highest in the youngest age groups.
  • If the clinical picture in a postmenopausal patient resembles PID, careful differential diagnosis is required (high risk of malignancy).
• In 2019, the global age-standardized prevalence rate (ASPR) of PID was 53.19 per 100 000. For details, see http://pmc.ncbi.nlm.nih.gov/articles/PMC10544469/.

Aetiology

• Usually a mixed infection, and the causative pathogens cannot necessarily be detected by microbiological methods.
  • Chlamydia trachomatisChlamydia and Neisseria gonorrhoeae Gonorrhoea often cause PID in women of reproductive age. An estimated 10-15% of cervical chlamydial or gonococcal infections proceed to PID.
  • Mycoplasma genitalium is another probable cause of PID in premenopausal patients.
  • Anaerobic bacteria in the vaginal microbiome may also be associated with PID.
  • Intestinal or respiratory tract bacteria are involved more rarely.
• Inserting an IUD will increase the risk of PID for a few weeks.

Clinical picture

• The possibility of PID must be kept in mind if a patient of reproductive age presents with lower abdominal pain and abnormal vaginal discharge. The clinical diagnosis can be made based on typical symptoms and findings and basic investigations.
• The clinical picture varies from nearly asymptomatic to life-threatening.
• Symptoms
  • Bilateral lower abdominal pain
    • Pain on intercourse, pain on urination
  • Abnormal vaginal discharge
    • Intermenstrual bleeding, postcoital bleeding, purulent discharge
  • Low-grade fever / fever
• Findings
  • Palpation of the abdomen: tenderness of the lower abdomen
  • Pelvic examination: cervical, uterine and adnexal tenderness
  • Speculum examination: purulent or bloody cervical discharge

Workup

Differential diagnosis

• Urinary tract infection Urinary Tract Infections
• Ectopic pregnancy Ectopic Pregnancy
• Ovarian cyst (rupture or torsion) Benign Gynaecological Lesions and Tumours
• Endometriosis Endometriosis
• Inflammatory diseases of the bowel (appendicitis Acute Appendicitis, diverticulitis Diverticulitis and Diverticulosis, Crohn's disease Crohn's Disease)

Treatment

• To avoid consequences affecting fertility, PID should be diagnosed and treatment started without hesitation in patients of reproductive age.
• Treatment should be chosen to cover the most important potential causative bacteria and also a mixed infection; treatment should be directed at chlamydia, gonorrhoea and anaerobic bacteria.
• Outpatient management if:
  • the patient's general condition is good
  • inflammatory markers are only slightly increased.
• Antimicrobial treatment in outpatient care
  • Doxycycline 100 mg twice daily for 14 days and metronidazole 400 mg three times daily for 14 days
  • If gonorrhoea is diagnosed
    • a single dose of ceftriaxone 1 g i.m. should be added to the regimen, and
    • a gonococcal culture sample should preferably be taken for antimicrobial susceptibility testing before starting the treatment (see Gonorrhoea).
  • If gonorrhoea or chlamydia is diagnosed, ensure contact tracing (see Chlamydia).
  • If chlamydial and gonococcal infections can be excluded and the infection occurs after the insertion of an IUD, for example, it is usually a mixed infection caused by normal vaginal flora.
    • This can be treated with a combination of cephalexin (500 mg three times daily or 750 mg twice daily) and metronidazole (500 mg twice daily or 400 mg three times daily).
• Indications for hospital treatment
  • Severe symptoms: high fever, poor general condition
  • Complicated PID: suspected abscess in the lesser pelvis
  • PID refractory to outpatient care
  • Uncertain diagnosis, differential diagnostic problems
  • Pregnant women
• Antimicrobial treatment in hospital
  • Ceftriaxone 2 g i.v. once daily, doxycycline 100 mg i.v. or p.o. twice daily, metronidazole 400 mg i.v. or p.o. three times daily
  • After the patient's clinical condition improves, intravenous antimicrobial treatment should be continued for another day. It can then be replaced by oral medication.
    • Doxycycline 100 mg twice daily and metronidazole 400 mg three times daily to make the total duration of treatment 14 days
• Symptomatic treatment: NSAID, rest, sick leave
• If a patient with PID has an IUD, it should be removed if PID is refractory to antimicrobial treatment.
  • Remember to arrange postcoital contraception and further contraception, as necessary.
• If PID was due to chlamydia or gonorrhoea, a control sample (nucleic acid detection test for chlamydia and gonorrhoea) should be taken 4 weeks after the end of treatment.
• The sexual partner(s) should be examined: samples for chlamydia and gonorrhoea tests.

Prognosis

• PID should be readily treated to prevent any late complications.
• PID may damage the fallopian tubes, leading to subfertility.
  • A single case of PID with treatment begun at an early stage will hardly affect fertility.
  • The risk of infertility is increased if the patient has had severe PID or several episodes of PID.
• PID may increase the risk of ectopic pregnancy to some extent.
• About 30% of patients develop chronic pelvic pain.