Pelvic inflammatory disease (PID) is defined as an inflammation of the upper genital tract due to an infection in women. The disease affects the uterus, fallopian tubes, and/or ovaries. It is typically an ascending infection, spreading from the lower genital tract. The majority of cases PID are related to a sexually transmitted infection. The diagnosis of PID is primarily clinical and should be suspected in female patients with lower abdominal or pelvic pain and genital tract tenderness. During the patient’s evaluation, other etiologies of pain including ectopic pregnancy should be considered and ruled out. PID is treated with antibiotics to cover the primary pathogens including Neisseria gonorrhoeae and Chlamydia trachomatis. Short-term complications include tubo-ovarian or pelvic abscess. Long-term complications include ectopic pregnancy, infertility, and chronic pelvic pain. Early diagnosis and treatment can potentially prevent complications.
Ascending infection from the cervix causes PID. In 85% of cases, the infection is caused by sexually transmitted bacteria. Of the offending agents, the bacteria Neisseria gonorrhoeae or Chlamydia trachomatis are the most common pathogens. Approximately 10% to 15% of women with endocervical N. gonorrhoeae or C. trachomatis will go on to develop PID. Typically, gonorrheal PID is more severe than PID due to other causes. PID due to chlamydia is less likely to cause symptoms, and therefore, more likely to result in subclinical PID. Subclinical PID can produce little to no symptoms, but can still have adverse long-term consequences.
Other cervical microbes, including Mycoplasma genitalium, have been thought to contribute to the disease. Additionally, pathogens responsible for bacterial vaginosis (Peptostreptococcus species, Bacteroides species), respiratory pathogens (Haemophilus influenza, Streptococcus pneumonia, Staphylococcus aureus), and enteric pathogens (Escherichia coli, Bacteroides fragilis, group B Streptococci) have been implicated in acute PID, and account for approximately 15% of cases overall.
PID occurs most frequently in women ages 15 to 25 years. In 2001 there were more than 750,000 cases of PID in the United States. Over the past decade, the rates of PID have been decreasing, but it is still commonly seen in both outpatient clinic and emergency department settings.
Infection of the upper female genital tract leads to inflammatory damage, resulting in scarring, adhesions, and partial or total obstruction of the fallopian tubes. This can result in loss of the ciliated epithelial cells along the fallopian tube lining, resulting in impaired ovum transport and increased risk for infertility and ectopic pregnancy. Additionally, adhesions can lead to chronic pelvic pain.
Endometrial biopsy is rarely done if there is a doubt about the diagnosis. The biopsy usually shows the presence of inflammation but the organism is never identified.
Women with PID may present with lower abdominal or pelvic pain, vaginal discharge, dyspareunia, and/or abnormal vaginal bleeding. Therefore, PID should be suspected in any young female presenting with lower abdominal pain and pelvic discomfort. Risk factors include intercourse with multiple partners, age, previous history of PID, intrauterine device implantation, and tubal ligation. As PID is primarily a clinical diagnosis, a thorough history and physical exam is crucial. Clarification of the onset and character of the pain should be obtained, while also exploring possible alternative diagnoses.
All women with suspected PID should have a pelvic examination to evaluate for cervical discharge, cervical motion tenderness, uterine tenderness, adnexal tenderness or masses. The diagnosis of pelvic inflammatory disease is clinical and is defined by lower genital tract inflammation such as cervical discharge, an increased number of white blood cells on wet prep, or cervical friability.
Laboratory evaluation should include a pregnancy test to exclude the possibility of an ectopic pregnancy as an alternate etiology of the pelvic pain. Additionally, practitioners should consider microscopy of vaginal or cervical discharge (if present) along with nucleic acid amplification tests (NAAT) for C. trachomatis and N. gonorrhoeae. Testing for other sexually transmitted infections like HIV and Treponema pallidum (syphilis) should be considered as well. Additionally, if there is a concern for a tubo-ovarian abscess, a pelvic ultrasound should be considered. 
As stated before, the diagnosis of pelvic inflammatory disease is primarily clinical. PID should be considered in any sexually active young woman with pelvic or low abdominal pain and evidence of genital tract tenderness on exam. While laboratory tests may help confirm the diagnosis, NAAT testing typically can take several hours to days to result depending on your institution. Negative results do not exclude the diagnosis. An ultrasound or CT without findings of PID does not exclude the diagnosis. Therefore, early and prompt treatment should be started based on clinical suspicion.
Indications for hospitalization include pregnancy, failed outpatient treatment, severe clinical illness, PID with pelvic abscess, or possible need for surgical intervention.
Empiric treatment for PID in the inpatient setting includes:
The CDC recommends the following for first-line treatment for outpatient therapy:
Metronidazole (500 mg orally twice per day for 14 days) should be added if there is a concern for trichomonas or recent vaginal instrumentation.
The differential when considering PID as a diagnosis also includes ectopic pregnancy, ovarian cyst rupture, ovarian torsion, endometriosis, cystitis, pyelonephritis, appendicitis, diverticulitis, traumatic injury, and pyelonephritis.
Delayed treatment of PID has a strong association with worsened outcomes and long-term complications. However, even with timely treatment, long-term complications can occur. One study estimated that for females with PID between 20 to 24 years of age, 18% would eventually develop chronic pain, 8.5% would develop ectopic pregnancies, and 16.8% would struggle with infertility.
Chronic pelvic pain is seen in as many as one-third of women with PID. The pain is thought to be related to inflammation, scarring, and adhesions from the infectious process. The strongest predictor of developing chronic pelvic pain related to PID is recurrent PID.
Infertility can also result from PID, regardless if the patient is symptomatic or asymptomatic from the pelvic infection. The infection can cause severe damage to the fallopian tubes, including loss of the ciliary epithelial cells of the fallopian tube and occlusion of the tube. The effects on fertility can be pronounced, with some studies indicating a 5-fold increase in infertility in women with a history of PID. Infertility related to PID is more likely to occur if chlamydia is the infectious cause, if there is a delay in treatment for PID, if the patient has recurrent episodes of PID, or if the case of PID is more severe.
The increased risk for ectopic pregnancy following PID is also related to damage to the fallopian tubes. In one study the rate of ectopic pregnancy following PID is approximately 7.8% according to one study, while the non-PID ectopic rate is 1.3%.
Besides a gynecologist, the emergency physician and an internist, nurses also play a vital role in the care of patients with PID. The major focus today is on patient education and preventing PID and sexually transmitted infections. Nurses should educate the patients about safe sex, use of a condoms, and reducing the number of sexual partners. Teenagers and adolescents should be asked to delay sexual activity until 16 or older. The pharmacist who usually dispenses the medication should ask the female to bring in the partner, who also needs to be assessed and treated for a sexually transmitted infection, otherwise, the cycle of infection will continue. (Level 1) Only through an integrated approach with emphasis on public health can the burden of PID be lowered. (Level V)
Patients with PID may develop chronic pain, an ectopic pregnancy, or infertility. About 25% will have chronic pelvic pain, usually due to adhesions. Impaired fertility affects 10-50% of females and is usually due to scarring and adhesions within the fallopian tubes. The rates of infertility usually increase with the number of infections episodes. The final problem is an ectopic pregnancy which may occur in 15-60% of women and is usually due to damage to the fallopian tubes. Some women may develop the Fitz Hugh Curtis Syndrome. Each year there are over 150,000 admissions related to PID. The complication rates in parts of Africa, Asia, and South America where health care is not readily accessible are very high. There are also reports that PID may be associated with a higher risk of stroke and ovarian cancer.  (Level III)