Pelvic inflammatory disease (PID) may affect the cervix, uterus, fallopian tubes, and/or ovaries. Infection of the cervix (cervicitis Cervicitis Cervicitis is infectious or noninfectious inflammation of the cervix. Findings may include vaginal discharge, vaginal bleeding, and cervical erythema and friability. Women are tested for infectious... read more 
) 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 of PID
PID results from microorganisms ascending from the vagina and cervix into the endometrium and fallopian tubes. Neisseria gonorrhoeae Gonorrhea Gonorrhea is caused by the bacteria Neisseria gonorrhoeae. It typically infects epithelia of the urethra, cervix, rectum, pharynx, or conjunctivae, causing irritation or pain and purulent discharge... read more 
and Chlamydia trachomatis Chlamydial, Mycoplasmal, and Ureaplasmal Mucosal Infections Sexually transmitted urethritis, cervicitis, proctitis, and pharyngitis not due to gonorrhea are caused predominantly by chlamydiae and infrequently by mycoplasmas or Ureaplasma sp. Chlamydiae... read more 
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 Bacterial Vaginosis (BV) Bacterial vaginosis is vaginitis due to a complex alteration of vaginal flora in which lactobacilli decrease and anaerobic pathogens overgrow. Symptoms include a gray, thin, fishy-smelling vaginal... read more 
. 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 of PID
Pelvic inflammatory disease commonly causes lower abdominal pain, fever, cervical discharge, and abnormal uterine bleeding, particularly during or after menses.
Cervicitis
In cervicitis Symptoms and Signs Cervicitis is infectious or noninfectious inflammation of the cervix. Findings may include vaginal discharge, vaginal bleeding, and cervical erythema and friability. Women are tested for infectious... read more , 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 of PID
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 Ectopic Pregnancy In ectopic pregnancy, implantation occurs in a site other than the endometrial lining of the uterine cavity—ie, in the fallopian tube, uterine cornua, cervix, ovary, or abdominal or pelvic cavity... read more , which can produce similar findings, should be considered.
Other common causes of pelvic pain Pelvic Pain Pelvic pain is discomfort in the lower torso; it is a common complaint in women. It is considered separately from perineal pain, which occurs in the external genitals and nearby perineal skin... read more include endometriosis Endometriosis In endometriosis, functioning endometrial tissue is implanted in the pelvis outside the uterine cavity. Symptoms depend on location of the implants and may include dysmenorrhea, dyspareunia... read more , adnexal torsion Adnexal Torsion Adnexal torsion is twisting of the ovary and sometimes the fallopian tube, interrupting the arterial supply and causing ischemia. Adnexal torsion is uncommon, occurring most often during reproductive... read more , ovarian cyst rupture Benign Ovarian Masses Benign ovarian masses include functional cysts and tumors; most are asymptomatic. Treatment varies depending on the patient's reproductive status. There are 2 types of functional cysts: Follicular... read more , and appendicitis Appendicitis Appendicitis is acute inflammation of the vermiform appendix, typically resulting in abdominal pain, anorexia, and abdominal tenderness. Diagnosis is clinical, often supplemented by CT or ultrasonography... read more 
. Differentiating features of these disorders are discussed elsewhere.
Fitz-Hugh-Curtis syndrome may mimic acute cholecystitis Acute Cholecystitis Acute cholecystitis is inflammation of the gallbladder that develops over hours, usually because a gallstone obstructs the cystic duct. Symptoms include right upper quadrant pain and tenderness... read more 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 Ectopic Pregnancy In ectopic pregnancy, implantation occurs in a site other than the endometrial lining of the uterine cavity—ie, in the fallopian tube, uterine cornua, cervix, ovary, or abdominal or pelvic cavity... read more , adnexal torsion Adnexal Torsion Adnexal torsion is twisting of the ovary and sometimes the fallopian tube, interrupting the arterial supply and causing ischemia. Adnexal torsion is uncommon, occurring most often during reproductive... read more ).
If the diagnosis is uncertain after ultrasonography, laparoscopy should be done; purulent peritoneal material noted during laparoscopy is the diagnostic gold standard.
Treatment of PID
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 Regimens for Treatment of Pelvic Inflammatory Disease* Pelvic inflammatory disease (PID) is a polymicrobial infection of the upper female genital tract: the cervix, uterus, fallopian tubes, and ovaries; abscess may occur. PID may be sexually transmitted... read more ) usually also aim to eradicate bacterial vaginosis Treatment Bacterial vaginosis is vaginitis due to a complex alteration of vaginal flora in which lactobacilli decrease and anaerobic pathogens overgrow. Symptoms include a gray, thin, fishy-smelling vaginal... read more , which often coexists.
Sex partners of patients with N. gonorrhoeae or C. trachomatis infection should be treated.
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 Regimens for Treatment of Pelvic Inflammatory Disease* Pelvic inflammatory disease (PID) is a polymicrobial infection of the upper female genital tract: the cervix, uterus, fallopian tubes, and ovaries; abscess may occur. PID may be sexually transmitted... read more ) 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 (1). 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).
Treatment reference
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1. Goje O, Markwei M, Kollikonda S, et al: Outcomes of minimally invasive management of tubo-ovarian abscess: A systematic review. J Minim Invasive Gynecol 28 (3):556–564, 2021. doi: 10.1016/j.jmig.2020.09.014
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).
