Pelvic Inflammatory Disease (PID)
Pelvic inflammatory disease (PID) may affect the cervix, uterus, fallopian tubes, and/or ovaries. Infection of the cervix (cervicitis) causes mucopurulent discharge. Infection of the fallopian tubes (salpingitis) and uterus (endometritis) tend to occur together. If severe, infection can spread to the ovaries (oophoritis) and then the peritoneum (peritonitis). Salpingitis with endometritis and oophoritis, with or without peritonitis, is often called salpingitis even though other structures are involved. Pus may collect in the tubes (pyosalpinx), and an abscess may form (tubo-ovarian abscess).
Etiology
PID results from microorganisms ascending from the vagina and cervix into the endometrium and fallopian tubes. Neisseria gonorrhoeae and Chlamydia trachomatis are common causes of PID; they are transmitted sexually. Mycoplasma genitalium, which is also sexually transmitted, can also cause or contribute to PID. Incidence of sexually transmitted PID is decreasing; < 50% of patients with acute PID test positive for gonorrhea or chlamydial infection.
PID usually also involves other aerobic and anaerobic bacteria, including pathogens that are associated with bacterial vaginosis. Vaginal microorganisms such as Haemophilus influenzae, Streptococcus agalactiae, and enteric gram-negative bacilli can be involved in PID, as can Ureaplasma sp. Vaginal inflammation and bacterial vaginosis help in the upward spread of vaginal microorganisms.
Risk factors
Symptoms and Signs
Pelvic inflammatory disease commonly causes lower abdominal pain, fever, cervical discharge, and abnormal uterine bleeding, particularly during or after menses.
Cervicitis
In cervicitis, the cervix appears red and bleeds easily. Mucopurulent discharge is common; usually, it is yellow-green and can be seen exuding from the endocervical canal.
Acute salpingitis
Lower abdominal pain is usually present and bilateral but may be unilateral, even when both tubes are involved. Pain can also occur in the upper abdomen. Nausea and vomiting are common when pain is severe. Irregular bleeding (caused by endometritis) and fever each occur in up to one third of patients.
In the early stages, signs may be mild or absent. Later, cervical motion tenderness, guarding, and rebound tenderness are common.
Occasionally, dyspareunia or dysuria occurs.
Many women with inflammation that is severe enough to cause scarring have minimal or no symptoms.
PID due to N. gonorrhoeae is usually more acute and causes more severe symptoms than that due to C. trachomatis, which can be indolent. PID due to M. genitalium, like that due to C. trachomatis, is also mild and should be considered in women who do not respond to first-line therapy for PID.
Complications
The Fitz-Hugh-Curtis syndrome (perihepatitis that causes upper right quadrant pain) may result from acute gonococcal or chlamydial salpingitis. Infection may become chronic, characterized by intermittent exacerbations and remissions.
A tubo-ovarian abscess (collection of pus in the adnexa) develops in about 15% of women with salpingitis. It can accompany acute or chronic infection and is more likely if treatment is late or incomplete. Pain, fever, and peritoneal signs are usually present and may be severe. An adnexal mass may be palpable, although extreme tenderness may limit the examination. The abscess may rupture, causing progressively severe symptoms and possibly septic shock.
Hydrosalpinx is fimbrial obstruction and tubal distention with nonpurulent fluid; it is usually asymptomatic but can cause pelvic pressure, chronic pelvic pain, dyspareunia, and/or infertility.
Salpingitis may cause tubal scarring and adhesions, which commonly result in chronic pelvic pain, infertility, and increased risk of ectopic pregnancy.
Diagnosis
Pelvic inflammatory disease is suspected when women of reproductive age, particularly those with risk factors, have lower abdominal pain or cervical or unexplained vaginal discharge. PID is considered when irregular vaginal bleeding, dyspareunia, or dysuria is unexplained. PID is more likely if lower abdominal, unilateral or bilateral adnexal, and cervical motion tenderness are present. A palpable adnexal mass suggests tubo-ovarian abscess. Because even minimally symptomatic infection may have severe sequelae, index of suspicion should be high.
If PID is suspected, PCR of cervical specimens for N. gonorrhoeae and C. trachomatis (which is about 99% sensitive and specific) and a pregnancy test are done. If PCR is unavailable, cultures are done. However, upper tract infection is possible even if cervical specimens are negative. At the point of care, cervical discharge is usually examined to confirm purulence; a Gram stain or saline wet mount is used, but these tests are neither sensitive nor specific.
If a patient cannot be adequately examined because of tenderness, ultrasonography is done as soon as possible.
The white blood cell count may be elevated but is not helpful diagnostically.
If the pregnancy test is positive, ectopic pregnancy, which can produce similar findings, should be considered.
Other common causes of pelvic pain include endometriosis, adnexal torsion, ovarian cyst rupture, and appendicitis. Differentiating features of these disorders are discussed elsewhere.
Fitz-Hugh-Curtis syndrome may mimic acute cholecystitis but can usually be differentiated by evidence of salpingitis during pelvic examination or, if necessary, with ultrasonography.
If an adnexal or pelvic mass is suspected clinically or if patients do not respond to antibiotics within 48 to 72 hours, ultrasonography is done as soon as possible to exclude tubo-ovarian abscess, pyosalpinx, and disorders unrelated to PID (eg, ectopic pregnancy, adnexal torsion).
If the diagnosis is uncertain after ultrasonography, laparoscopy should be done; purulent peritoneal material noted during laparoscopy is the diagnostic gold standard.
Treatment
Antibiotics are given empirically to cover N. gonorrhoeae and C. trachomatis and are modified based on laboratory test results. Empirical treatment is needed whenever the diagnosis is in question for several reasons:
Patients with cervicitis or clinically mild to moderate PID do not require hospitalization. Outpatient treatment regimens (see table Regimens for Treatment of Pelvic Inflammatory Disease) usually also aim to eradicate bacterial vaginosis, which often coexists.
Sex partners of patients with N. gonorrhoeae or C. trachomatis infection should be treated.
Regimens for Treatment of Pelvic Inflammatory Disease*
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Treatment |
Regimen |
Alternative Regimens |
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Parenteral† |
Regimen A: Cefotetan 2 g IV every 12 hours or Cefoxitin 2 g IV every 6 hours plus Doxycycline 100 mg orally or IV every 12 hours Regimen B: Clindamycin 900 mg IV every 8 hours plus Gentamicin 2 mg/kg (loading dose) IV or IM, followed by a maintenance dose (1.5 mg/kg) every 8 hours; possibly substitution of single daily dosing (3–5 mg/kg once a day) |
Ampicillin/sulbactam 3 g IV every 6 hours plus Doxycycline 100 mg orally or IV every 12 hours
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Oral and IM‡ |
Regimen A: Ceftriaxone 250 mg IM in a single dose plus Doxycycline 100 mg orally twice a day for 14 days with or without Metronidazole 500 mg orally twice a day for 14 days Regimen B: Cefoxitin 2 g IM in a single dose with probenecid 1 g orally given concurrently in a single dose plus Doxycycline 100 mg orally twice a day for 14 days with or without Metronidazole 500 mg orally twice a day for 14 days Regimen C: Another parenteral 3rd-generation cephalosporin (eg, ceftizoxime, cefotaxime) plus Doxycycline 100 mg orally twice a day for 14 days with or without Metronidazole 500 mg orally twice a day for 14 days |
Regimen D: Azithromycin 500 mg IV once a day in 1 or 2 doses, followed by 250 mg orally once a day for 12–14 days with or without Metronidazole 500 mg orally twice a day for 14 days Regimen E: Azithromycin 1 g orally once a week for 2 weeks plus Ceftriaxone 250 mg IM in a single dose with or without Metronidazole 500 mg orally twice a day for 14 days Regimen F:§ A fluoroquinolone (eg, levofloxacin 500 mg orally once a day, ofloxacin 400 mg orally twice a day, or moxifloxacin 400 mg orally once a day for 14 days) plus Metronidazole 500 mg orally twice a day for 14 days |
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* Recommendations are from the Centers for Disease Control and Prevention: Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR 64 (RR3):1–137, 2015. Available at www.cdc.gov/std/treatment. |
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† Clinical efficacy of parenteral and oral therapy for mild to moderately severe pelvic inflammatory disease (PID) appears similar. Clinical experience should guide the transition to oral therapy, which can usually be started within 24–48 hours of clinical improvement. |
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‡ Oral therapy can be considered for mild to moderately severe acute PID because the clinical outcomes with oral and parenteral therapy are similar. If patients do not respond to oral therapy within 72 hours, they should be reevaluated to confirm the diagnosis, and parenteral therapy should be given on an outpatient or inpatient basis. |
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§ This regimen may be considered if parenteral cephalosporin is not feasible, if community prevalence and individual risk of gonorrhea are low, and if follow-up is likely. Tests for gonorrhea must be done before therapy is started; if results are positive, the following is recommended: |
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If patients do not improve after treatment that covers the usual pathogens, PID due to M. genitalium should be considered. Patients can be treated empirically with moxifloxacin 400 mg orally once a day for 7 to 14 days (eg, for 10 days).
Women with PID are usually hospitalized if any of the following are present:
In these cases, IV antibiotics (see table Regimens for Treatment of Pelvic Inflammatory Disease) are started as soon as cultures are obtained and are continued until patients have been afebrile for 24 hours.
Tubo-ovarian abscess may require more prolonged IV antibiotic treatment. Treatment with ultrasound- or CT-guided percutaneous or transvaginal drainage can be considered if response to antibiotics alone is incomplete. Laparoscopy or laparotomy is sometimes required for drainage. Suspicion of a ruptured tubo-ovarian abscess requires immediate laparotomy. In women of reproductive age, surgery should aim to preserve the pelvic organs (with the hope of preserving fertility).
Key Points
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The sexually transmitted pathogens Neisseria gonorrhoeae and Chlamydia trachomatis are common causes of PID, but infection is often polymicrobial.
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PID can cause tubal scarring and adhesions, which commonly result in chronic pelvic pain, infertility, and increased risk of ectopic pregnancy.
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Because even minimally symptomatic infection may have severe sequelae, index of suspicion should be high.
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PCR and cultures are accurate tests; however, if results are not available at the point of care, empiric treatment is usually recommended.
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Hospitalize women with PID based on clinical criteria (see above).
