Pelvic Inflammatory Disease

BASICS

DESCRIPTION

  • Pelvic inflammatory disease (PID) is an infection of the upper female genital tract, including the uterus, fallopian tubes, ovaries, and surrounding structures. PID is most commonly an ascending polymicrobial infection acquired through retrograde movement of microorganisms from the lower genital tract.
  • PID is concerning due to its potential impact on fertility.
  • Mild to moderate PID is characterized by the absence of a tubo-ovarian abscess (TOA). Severe disease is defined as severe systemic symptoms or presence of a TOA.
  • Diagnosis is challenging due to nonstandardized definitions, lack of definitive tests, and variations in symptoms. (1)[C]

EPIDEMIOLOGY

Most commonly affects sexually active patients aged 15 to 24 years (1)[C].

Incidence

>1 million patients are diagnosed with PID annually.

Prevalence

Estimated prevalence of lifetime PID is 4.4% in sexually active cisgender women aged 18 to 44 years. ~2.5 million women of reproductive age in the United States have had a PID diagnosis.

  • Without a history of prior STI, lifetime prevalence is higher in black than white women (6% vs. 2.7%).
  • With a history of STI, lifetime prevalence is similar across races (10% vs. 10.3%).

ETIOLOGY AND PATHOPHYSIOLOGY

Multiple organisms cause PID, and polymicrobial infections are common.

  • Chlamydia trachomatis and Neisseria gonorrhoeae, previously thought to be the most commonly implicated pathogens in PID, are now identified in only 22–50% of cases.
  • Mycoplasma genitalium infection was seen in 10% of those diagnosed with PID, with the latest study showing a 67% increase in odds of developing PID with an M. genitalium infection (2)[A]
  • Common flora and causes of bacterial vaginosis including aerobic and anaerobic species, and vaginal microbes (e.g., Gardnerella vaginalis and Escherichia coli) are increasingly implicated (2)[A]
  • Possible mechanisms for ascent from the lower genital tract include: (i) travel from cervix to endometrium to salpinx to peritoneal cavity; (ii) lymphatic spread via infection of the parametrium; and (iii) hematogenous route, although this is rare.

RISK FACTORS

  • Sexually active and age <25 years
  • New sexual partner or sexual partner with symptoms or known STI
  • ≥2 sexual partners in the last year (1)[C]
  • Inconsistent condom use
  • Gynecologic procedures that break the cervical barrier include endometrial biopsy, curettage, hysterosalpingography (HSG), hysteroscopy, in vitro fertilization, and IUD insertion of IUD in the last 3 weeks.
  • Other factors associated with PID:
    • Previous history of PID (10–25% recurrence)
    • Cervical ectopy
    • History of C. trachomatis; 10–40% develop PID
    • History of gonococcal cervicitis; 10–20% develop PID (3)[A]

GENERAL PREVENTION

  • Educational programs about safe sex practices such as barrier contraceptive use.
  • The U.S. Preventive Services Task Force recommends annual chlamydia screening in all sexually active women aged <25 years and in those aged ≥25 years at increased risk (new sex partner/multiple sex partners), with moderate evidence suggesting that it reduces cases of PID (1)[C].
  • Routine STI screening in pregnancy
  • STI screenings for those with new genital lesions or abnormal discharge

COMMONLY ASSOCIATED CONDITIONS

  • In a patient with an IUD and a pelvic abscess, suspect Actinomyces infection and treat with penicillin.
  • Rupture of an adnexal abscess is rare but life-threatening, requiring early surgical exploration (1)[C].
  • Chlamydial or gonococcal perihepatitis, called Fitz-Hugh-Curtis syndrome, can accompany PID, causing severe pleuritic right upper quadrant pain, in 4–6% of PID cases (2)[A].

DIAGNOSIS

HISTORY

  • Lower abdominal/pelvic pain: dull, aching or crampy, bilateral, constant; worsened by motion, exercise, or coitus
  • New/abnormal vaginal discharge (~75% of cases) or unanticipated/post-coital bleeding (~40% of cases)
  • Fever, chills, dyspareunia
  • Low back pain
  • Dysuria
  • Recent HSG or other procedure breaking the uterine barrier
  • IUD insertion in the past 21 days

PHYSICAL EXAM

Fever; lower abdominal pain; cervical motion, uterine, or adnexal tenderness; evidence of cervicitis with/without vaginal discharge

DIFFERENTIAL DIAGNOSIS

Appendicitis, constipation, gastroenteritis, ectopic pregnancy, ovarian tumor/torsion, hemorrhagic/ruptured ovarian cyst, endometriosis/dysmenorrhea, functional pelvic pain, inflammatory bowel disease, diverticulitis, UTI/pyelonephritis, nephrolithiasis

DIAGNOSTIC TESTS & INTERPRETATION

Initial Tests (lab, imaging)

  • Pregnancy test
  • Chlamydia and gonorrhea testing with urine or cervical swab nucleic acid amplification test (NAAT); a negative result does not exclude PID.
  • Urinalysis
  • Saline microscopy of vaginal fluid
  • HIV test and syphilis screening test
  • Transvaginal ultrasound

Pediatric Considerations
Consider sexual abuse in children presenting with PID.

Follow-Up Tests & Special Considerations

Follow up ultrasound as an outpatient for resolution of TOA.

Diagnostic Procedures/Other

  • Consider laparoscopy in ill patients with a competing diagnosis, failed outpatient treatment, or lack of improvement after 72 hours of inpatient treatment.
  • Endometrial biopsy (indicated only if laparoscopy shows no evidence of salpingitis) reveals endometritis.

Test Interpretation

If suspicion is high, treat empirically since NAAT tests take 1 to 3 days to result (1)[C].

TREATMENT

GENERAL MEASURES

  • IUD removal is NOT required for PID unless no improvement occurs within 48 to 72 hours of treatment.
  • Treatment should cover principal pathogens (CT, NG, and polymicrobial infections with anaerobic coverage), regardless of test results (3)[A].

MEDICATION

First Line

Outpatient treatment regimen: long-acting cephalosporin, macrolide or tetracycline, and metronidazole.

  • Ceftriaxone 500 mg IM single dose plus doxycycline 100 mg PO BID for 14 days plus metronidazole 500 mg PO BID for 14 days; patients weighing >150 kg need 1 g of ceftriaxone.
  • As of 2021, CDC recommends adding PO metronidazole to the standard outpatient regimen.
  • Can also consider moxifloxacin 400 mg, PO QID monotherapy for 14 days, for mild to moderate PID, especially if the patient has a cephalosporin allergy (3)[A]; moxifloxacin offers the best coverage against M. genitalium, but it is not advised if local population has high incidence of fluoroquinolone-resistant gonorrhea infections (2)[A].

Second Line

  • Because of emerging resistance, culture for sensitivity testing and cure is advised 2 weeks after completion of treatment.
  • Outpatient treatment regimen
    • Cefoxitin 2 g IM single dose and probenecid 1 g PO single dose, or cefotaxime (1 g IM), or ceftizoxime (1 g IM) plus doxycycline 100 mg PO BID for 14 days plus metronidazole 500 mg PO BID for 14 days
  • In persons with documented severe allergic reactions to penicillin:
    • Skin testing is important to confirm or refute penicillin allergy.
    • Cross-reactivity between penicillin and third-generation cephalosporins is low (<1%) (1)[C].
    • Levofloxacin 500 mg PO BID for 14 days can be substituted for cephalosporins.
  • Special consideration
    • Treat sex partners from the last 60 days. If recent sexual encounter was >60 days prior, treat the most recent partner. Administer expedited partner therapy when possible (1)[C].
    • Treat HIV-infected patients with acute PID like non–HIV-infected patients but monitor closely for TOA, especially if they have low CD4 counts (<200/mm3).

SURGERY/OTHER PROCEDURES

Reserved for failures of medical treatment and suspected ruptured adnexal abscess with resulting acute surgical abdomen.

ADMISSION, INPATIENT, AND NURSING CONSIDERATIONS

  • Criteria for hospitalization if any of the following:
    • Surgical emergencies (e.g., appendicitis) cannot be excluded.
    • Pregnancy
    • TOA
    • Severe illness, nausea or vomiting, unable to follow or tolerate outpatient regimen, or fever >101°F
    • Failure to respond to 72 hours of or al antibiotics (1)[C]
  • For inpatient treatment of PID, the CDC recommends the following:
    • Parenteral regimen A
      • Ceftriaxone 1 g IV every 24 hours plus doxycycline 100 mg PO or IV every 12 hours plus metronidazole 500 mg PO or IV every 12 hours
      • Alternatively, cefotetan 2 g IV BID or cefoxitin 2 g IV every 6 hours plus doxycycline 100 mg PO or IV BID; this regimen does not require additional anaerobic coverage with metronidazole.
      • Parenteral therapy for 24 to 48 hours after clinical improvement; oral doxycycline should be preferred when possible due to its similar bioavailability to IV. Continue doxycycline and metronidazole for a total of 14 days.
    • Parenteral regimen B
      • Clindamycin 900 mg IV every 8 hours plus gentamicin loading dose IV or IM (2 mg/kg of body weight) followed by a maintenance dose (1.5 mg/kg) every 8 hours or single daily dosing at 3 to 5 mg/kg can be substituted.
      • Parenteral therapy may be discontinued 24 hours after clinical improvement, and oral therapy with doxycycline as aforementioned or clindamycin 450 mg PO QID for a total of 14 days should be continued.
    • Parenteral regimen C: ampicillin/sulbactam 3 g IV every 6 hours doxycycline 100 mg PO or IV BID
  • PID in pregnant patients requires hospitalization, infectious disease consultation, and parenteral antibiotics due to the high risk for maternal morbidity, perinatal mortality, and preterm delivery (1)[C].

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

  • Follow up 72 hours after initiation of treatment, particularly for patients with moderate or severe clinical presentation.
  • Observe for worsening symptoms (fever, abdominal pain, and cervical motion tenderness).
  • Retest for gonorrhea and chlamydia 3 months post-treatment (1)[C].
  • Follow adnexal abscess size and position with serial ultrasounds.

PATIENT EDUCATION

  • Abstinence from sexual contact until complete treatment of patient/partner.
  • Consistent and correct condom use
  • Hepatitis B and human papillomavirus (HPV) vaccines should be given for those who meet the criteria.
  • Advise comprehensive STI screening.
  • Offer HIV preexposure prophylaxis (PEP) to patients with new STI or PID.
  • IUD insertion presents a low risk of PID in the setting of prior/current STI diagnosis.

PROGNOSIS

  • PID has a high morbidity; about 18% become infertile, 29% develop chronic pelvic pain, and 0.6% have an ectopic pregnancy.
  • Good prognosis with early effective therapy
  • Poor prognosis with delayed treatment
  • Nongonococcal, nonchlamydial PID is associated with severe PID and a worse prognosis for future fertility.

COMPLICATIONS

  • TOA occurs in 7–16% of patients before presentation; 1/3 of patients are hospitalized with PID.
  • Recurrent infection occur in 20–25% of patients.
  • Risk of ectopic pregnancy is increased 7- to 10-fold among those with a history of PID.
  • Tubal infertility in 8%, 19.5%, and 40% of patients after 1, 2, and 3 episodes of PID, respectively.
  • Chronic pelvic pain in 20–30% of cases is related to adhesions, chronic salpingitis, or recurrent infection.
  • Hydrosalpinx: After PID resolves, fallopian tube fills with sterile fluid and becomes blocked; associated with pain and infertility

Authors

Chirag N. Shah, MD
Daniel Scott Morrison, MD
Rahul Nayar, MD, DO

REFERENCES

  1. Shroff S. Infectious vaginitis, cervicitis, and pelvic inflammatory disease. Med Clin North Am. 2023;107(2):299–315. doi: 10.1016/j.mcna.2022.10.009.  [PMID:36759099]
  2. Htaik K, Vodstrcil LA, Plummer EL, et al. Systematic review and meta-analysis of the association between Mycoplasma genitalium and pelvic inflammatory disease (PID). Clin Infect Dis. 2024:ciae295. doi:10.1093/cid/ciae295  [PMID:38845565]
  3. Chen F, Dong Q, Hong W, et al. Moxifloxacin monotherapy for treatment of uncomplicated pelvic inflammatory disease: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials. Pharmacoepidemiol Drug Saf. 2023;32(11):1189–1199. doi:10.1002/pds.5677  [PMID:37655831]

ADDITIONAL READING

Centers for Disease Control and Prevention: https://www.cdc.gov/std/treatment-guidelines/pid.htm

CODES

ICD10

  • N70.0 Acute salpingitis and oophoritis
  • N70 Salpingitis and oophoritis
  • N71.0 Acute inflammatory disease of uterus
  • N73.9 Female pelvic inflammatory disease, unspecified
  • N73.0 Acute parametritis and pelvic cellulitis
  • N70.93 Salpingitis and oophoritis, unspecified
  • N73.1 Chronic parametritis and pelvic cellulitis
  • N73.5 Female pelvic peritonitis, unspecified
  • N73.4 Female chronic pelvic peritonitis
  • N73.8 Other specified female pelvic inflammatory diseases
  • N73.3 Female acute pelvic peritonitis
  • N73.2 Unspecified parametritis and pelvic cellulitis

SNOMED

  • 442506007 inflammatory disease of female genital structure (disorder)
  • 198156004 Acute parametritis (disorder)
  • 46536000 Tubo-ovarian inflammatory disease (disorder)
  • 237044002 Chronic pelvic inflammatory disease (disorder)
  • 237037006 Acute pelvic inflammatory disease (disorder)
  • 237045001 Chronic parametritis (disorder)

CLINICAL PEARLS

Last Updated: 2026

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