Pelvic inflammatory disease (PID)

Assessing Risk Microbiology and Pathophysiology Pathogenesis Diagnostic Principles Diagnostic Techniques Special Considerations Treatment and Supportive Care Sequelae Prevention

Pelvic inflammatory disease (PID) is a spectrum of inflammatory disorders within the female upper genital tract. The condition may include any combination of endometritis, salpingitis, tubo-ovarian abscess, and pelvic peritonitis. PID remains a major public health problem. Although chlamydial and gonorrheal cervicitis are reportable diseases in most states, PID is not.

Each year at least 1 million women in the United States (one fifth of them teenagers) are diagnosed with PID. More than 200,000 women are hospitalized for PID at an estimated total cost of more than $5 billion. At least one fourth of women with PID suffer severe sequelae such as infertility, ectopic pregnancy, or chronic pelvic pain. The same proportion are at risk for major abdominal surgery such as drainage of a tubo-ovarian abscess or lysis of a pelvic adhesion. Although the condition in most young patients is not life-threatening, repeated episodes of PID may threaten fertility.

Assessing Risk of Pelvic inflammatory disease

By determining each patient's risk for PID, the clinician is more likely to diagnose the condition accurately and to identify women who would benefit from counseling about risk reduction. Risks for sexually transmitted disease (STD) and for PID overlap considerably (Table 1).

The intrauterine device (IUD) has long been considered a risk factor for PID and infertility. However, most cases of PID in users of current copper and progestin-containing "T" IUDs in the United States now seem to be related to insertion of the device.

Further risk for PID in an individual patient correlates with her risk of acquiring new STDs. An important risk factor for PID is the extent of her health-seeking behavior and that of her sex partner or partners. A delay in treatment of only 1 or 2 days, for example, increases the likelihood of hospitalization by nearly 10%. In contrast, initiating treatment within 3 days of onset of symptoms reduces by 3-fold the risk of subsequent infertility and ectopic pregnancy.

Microbiology and Pathophysiology of Pelvic inflammatory disease

PID results from an ascending infection of bacteria that have colonized the endocervix. PID is usually polymicrobial and may involve both aerobic and anaerobic bacteria. The sexually transmissible organisms that are most frequently implicated include Neisseria gonorrhoeae, Chlamydia trachomatis, and genital mycoplasia. Approximately one third of women who have untreated gonococcal or chlamydial cervicitis progress to PID.

Pathogenesis

The pathogenesis of PID has not yet been fully explained. The correlation is poor between cultures taken from the cervix and those taken from the endometrium, salpinges, and abdominal spaces. Anaerobic bacteria are almost always identified in intratubal, ovarian, and pelvic abscesses, yet chlamydiae and gonococci are uncommon even when cervical gonorrhea or chlamydial infection is implicated as the initial cause of PID.

Pelvic inflammatory disease Diagnostic Principles

Laparoscopy is currently the diagnostic standard, yet PID is correctly diagnosed on clinical and laboratory indicators in only 65% of cases. No historical, physical, or laboratory findings conclusively diagnose PID. The ultimate diagnosis relies on clinical judgment coupled with empiric therapeutic intervention and careful follow-up. 

Confirming additional criteria improves diagnostic accuracy in patients with severe symptoms. Failure to rule out competing diagnoses, such as appendicitis and ectopic pregnancy, places patients at risk for morbidity related to delayed treatment.

In women with PID, all laboratory studies may be normal or, if abnormal, may provide supportive rather than confirmatory evidence. If possible, the clinician should recommend that the partner be examined as well. A urethral Gram stain and positive cultures for gonorrhea and chlamydia in men whose female partners are being evaluated for PID provide supportive evidence. Cervical cultures that are positive for N. gonorrhoeae or Chlamydia strongly support the diagnosis of PID if found with cervical motion tenderness, adnexal tenderness, or both.

Pelvic inflammatory disease Diagnostic Techniques

Although culdocentesis can be used to diagnose PID, other diagnostic methods are preferable. Culdocentesis samples material in the posterior cul-de-sac by intravaginal needle aspiration. An aspirate laden with white cells with or without organisms suggests acute PID but also may be seen with appendicitis and other intra-abdominal infections. Aspiration is not widely used in the United States to diagnose PID because it provides nonspecific information and is painful.

Pelvic ultrasound scans via endovaginal probe assist the clinician in assessing pelvic structures, especially in patients whose abdominal tenderness or obesity precludes palpating for abnormalities. Ultrasound scans may uncover pelvic abscesses and help the clinician to localize an ectopic pregnancy in patients with a positive pregnancy test.

An endometrial biopsy provides a histopathologic evaluation of aspirated transcervical specimens. Although this technique has demonstrated diagnostic value, the results may not be available for more than 24 hours. At present, endometrial biopsy is not widely practiced in the United States because infection is often a stated contraindication to the procedure.

The best method for diagnosing PID is laparoscopy, which is indicated for patients with an uncertain diagnosis. Laparoscopic evidence of PID includes hyperemia of the tubal surface, edema of tubal walls, and sticky exudate on the tubal surface or fimbriated ends. Unfortunately, laparoscopy is expensive, cumbersome, and not without risks. It usually must be performed on hospitalized patients with suspected PID who fail to improve or in whom diagnostic confusion persists. An undiagnosed pelvic mass or nonresponding pelvic abscess often warrants laparoscopic clarification.

Direct culture, diagnostic biopsies, or both may be obtained during laparoscopy to confirm the diagnosis, identify pathogens, and assist in the selection of antibiotics. During laparoscopy, the surgeon may remove free purulent matter, aspirate pyosalpinges, and perform lysis of adhesions; all of these methods are believed to promote recovery.

Special Considerations of Pelvic inflammatory disease

PID presents a special challenge when it occurs during pregnancy. PID rarely complicates early pregnancy. Both ectopic pregnancy and PID present with considerable overlap of symptoms and signs. Clinicians should perform pregnancy testing on all patients presenting with PID symptoms. Failure to diagnose an ectopic pregnancy puts the patient at risk for ectopic rupture and death. HIV testing and counseling should be provided for patients with confirmed or suspected cervical gonorrhea, chlamydia, or PID.

Treatment and Supportive Care for Pelvic inflammatory disease

The clinician should institute empiric treatment upon suspecting the presence of PID. Whether or not to hospitalize the patient is a critical decision. The majority of women with PID are treated as outpatients. Most authorities recommend hospitalization and parenteral therapy when compliance with recommended treatment is doubtful.

Antibiotic therapy should be initiated even before culture results are returned. Treatment must include broad-spectrum coverage (aerobic, anaerobic, and chlamydial) to address the wide range of potential pathogens. The CDC's revised regimens for outpatient and inpatient treatment take into account newer antibiotics as well as the emergence of resistant organisms. Single-drug oral regimens for outpatient treatment of PID are not recommended.

Supportive measures include pain management and ensuring adequate hydration.

All patients undergoing therapy for PID require careful follow-up. Hospitalized patients should undergo a daily bimanual examination so that the clinician can assess therapeutic effectiveness. Outpatients treated for PID should be re-examined within 72 hours of the initiation of treatment to ensure improvement and compliance with the recommended therapy.

Abdominal tenderness, cervical motion tenderness, and adnexal tenderness as well as the resolution of fever and malaise should be expected within 72 hours. Lack of significant improvement requires hospitalization, parenteral therapy, and reaffirmation of diagnosis. Follow-up cultures of the cervix are generally advised after antibiotic therapy has been completed.

Sequelae

All consequences of PID are potentially serious. Nearly 25% of patients experience a recurrence. Nearly 20% of women with acute PID suffer from chronic abdominal pain syndromes, which are most likely related to intra-abdominal adhesions. The risk of infertility increases with each bout of PID; nearly half of women who have 3 episodes or more become infertile after the third episode. The risk for ectopic pregnancy can increase from 2-fold to 10-fold above baseline after 1 episode.

Pelvic inflammatory disease Prevention

In the great majority of cases, PID results from sexual exposure. For the majority of women at risk, prevention of PID parallels efforts to prevent STDs. More rarely, postsurgical PID is related to uterine instrumentation such as IUD insertion, hysterosalpingography, elective abortion, or dilation and curettage. Recent evidence suggests a correlation of increased post-procedure infection in women with bacterial vaginosis. Some clinicians advocate treatment of this common condition before uterine instrumentation is performed.

Antibiotic prophylaxis with doxycycline has been shown to decrease infection related to IUD insertion.
TABLE 1 Correlation of risks for PID and STDs

Legend for Chart:

A - Risk variable
B - Acquisition of STD
C - Development of PID

                                                        A     B     C

Age

<25 years: 75% of cases and 10-fold              +     +
increased risk; 3-fold increased risk if
intercourse before age 15

Marital status

Increased risk with single status,                   +     +
divorce, separation

Contraceptive practice

Barrier method                                            -     -
Oral contraceptives                                     +     -
Intrauterine device                                            +

Menstrual cycle

Risk increases during or shortly after menses    +     +

Douching

>3 times per month                                    *     +

Smoking

Smokers have twice the risk of                     +     +
nonsmokers

+ = increased risk;    - = decreased risk;    * = no association reported.

Last updated Jan 4/07