Pelvic Inflammatory Disease: Infection of the Upper Reproductive Tract

Pelvic inflammatory disease, usually called PID, is infection and inflammation affecting the upper reproductive tract. It can involve the womb, fallopian tubes, ovaries and surrounding tissues. Symptoms may be severe, mild or absent, so treatment often begins before every test result is available.

What pelvic inflammatory disease is Pelvic inflammatory disease, usually called PID, is infection and inflammation affecting the upper reproductive tract. It may involve the lining of the womb, the fallopian tubes, the ovaries and the tissues surrounding these organs. PID usually develops when bacteria move upwards from the vagina or cervix. This movement is often described as an ascending infection. The term PID covers a group of related conditions rather than one precisely located infection. These include endometritis, salpingitis, oophoritis, tubo ovarian abscess and pelvic peritonitis. PID can affect anyone who has the relevant reproductive organs. It should not be assumed from gender identity, sexual orientation or relationship status. The lower and upper reproductive tracts The vagina and cervix form the lower reproductive tract. The womb, fallopian tubes and ovaries form the upper reproductive tract. An infection can begin at the cervix without causing obvious upper tract disease. In some people, bacteria then move beyond the cervix and trigger inflammation higher in the pelvis. Inflammation within the fallopian tubes can damage their delicate lining. Healing may produce scarring or adhesions that interfere with normal tubal function. Early treatment aims to stop ongoing infection and reduce further damage. Antibiotics cannot reliably reverse scarring that has already formed. Chlamydia and gonorrhoea are important causes Chlamydia and gonorrhoea are sexually transmitted bacterial infections that can ascend from the cervix and cause PID. Both infections may be present without noticeable genital symptoms. A person may therefore develop PID without knowing that an STI was present. Chlamydia and gonorrhoea are important causes, but they do not explain every case of PID. UK evidence suggests they account for a minority of cases overall. A positive chlamydia or gonorrhoea test supports the diagnosis and helps guide partner treatment. A negative result does not exclude PID. Other bacteria can cause PID PID is often polymicrobial, meaning that more than one type of bacterium may be involved. Bacteria normally found within the vagina can contribute when they move into the upper reproductive tract. Anaerobic bacteria, which can grow where oxygen levels are low, are included among these organisms. Mycoplasma genitalium is a sexually transmitted bacterium associated with PID. Current BASHH guidance recommends testing for it when signs and symptoms suggest PID, where testing is available. Treatment for confirmed Mycoplasma genitalium requires specialist interpretation because antibiotic resistance is common and standard PID treatment may not eradicate it reliably. PID may also develop after childbirth, miscarriage, abortion, hysteroscopy or another procedure that opens the cervix. This does not mean that these procedures usually cause infection. Intrauterine contraception and PID An intrauterine device or system does not continually cause PID. Any increased risk is mainly concentrated within the first few weeks after insertion. This early risk is thought to relate mainly to an infection already present when the device was fitted. An intrauterine device does not automatically need to be removed when PID is diagnosed. The clinician considers symptom severity, response to antibiotics, pregnancy risk and the person's contraceptive preferences. Removal without an alternative contraception plan can create an unintended pregnancy risk. Decisions should therefore be made with the treating clinician. Symptoms vary widely Lower abdominal or pelvic pain is the most commonly recognised symptom. It is often present on both sides but can be more noticeable on one side. Pain may begin over a few days or develop gradually. It may be constant, intermittent or mistaken for menstrual discomfort. Other possible symptoms include pain felt deeply during sex, unusual vaginal discharge and bleeding between periods or after sex. Periods may become heavier, more painful or different from usual. Some people experience discomfort when passing urine, nausea, fever or a general feeling of illness. None of these symptoms is specific to PID. Several gynaecological, urinary, gastrointestinal and pregnancy related conditions can produce a similar pattern. PID may be mild or asymptomatic Some people with PID have severe pain and fever. Others have only mild discomfort, unusual bleeding or a subtle change in discharge. PID can occasionally produce no recognised symptoms. This is sometimes called asymptomatic or subclinical PID. Mild disease matters because inflammation may still affect the fallopian tubes. A lack of fever or severe pain does not prove that the upper reproductive tract is unaffected. The symptoms and examination findings of PID are imperfect. This is one reason clinicians use a low threshold for treatment when the overall pattern is concerning. Not every person with chlamydia, gonorrhoea or Mycoplasma genitalium has PID. Upper tract disease requires clinical assessment rather than assumption from an STI result alone. Pelvic pain has many possible causes Ectopic pregnancy is an important alternative diagnosis because it can cause pelvic pain, vaginal bleeding and collapse. Appendicitis, urinary infection, kidney stones, endometriosis, ovarian cyst rupture and ovarian torsion can also resemble PID. Miscarriage, bowel inflammation, constipation and muscular pain may produce overlapping symptoms. The clinician must assess whether PID is likely while also looking for conditions requiring different or immediate treatment. A diagnosis of PID should not be used to dismiss severe, localised or rapidly worsening pain. Pregnancy must be considered A pregnancy test is an important part of assessing reproductive age people with pelvic pain, even when pregnancy seems unlikely. PID during an established pregnancy is uncommon. Pelvic pain and bleeding in pregnancy require assessment for ectopic pregnancy, miscarriage and other urgent conditions. One sided lower abdominal pain, vaginal bleeding, shoulder tip pain, dizziness or fainting can indicate an ectopic pregnancy. A ruptured ectopic pregnancy can cause life threatening internal bleeding. Emergency assessment must not be delayed while considering PID. Pregnant people with suspected PID generally require urgent specialist assessment and hospital based treatment because antibiotic choices and pregnancy risks differ. Fitz Hugh Curtis syndrome PID can sometimes inflame the tissue surrounding the liver. This complication is called Fitz Hugh Curtis syndrome. It may cause sharp pain beneath the ribs on the right side. Pain can be worse with breathing or movement and may spread towards the right shoulder. The liver cells themselves are not necessarily infected or damaged. The inflammation mainly affects the tissue covering the liver. Right upper abdominal pain has many other causes. Fitz Hugh Curtis syndrome cannot be diagnosed from the pain location alone. Tubo ovarian abscess Severe PID can produce a collection of pus involving a fallopian tube, ovary or both. This is called a tubo ovarian abscess. Possible features include marked pelvic pain, fever, vomiting, abdominal tenderness and significant systemic illness. An abscess can rupture and cause widespread infection within the abdomen. This is a medical and surgical emergency. Hospital treatment usually involves intravenous antibiotics. Drainage using imaging guidance or surgery may be required when the abscess is large, ruptured or not responding. How clinicians assess possible PID The clinician asks when the pain began, where it is felt and whether it is worsening. They ask about bleeding, discharge, fever, urinary symptoms, vomiting and pain during sex. Questions may include the last menstrual period, pregnancy possibility, contraception, previous PID, recent procedures and current or recent sexual partners. A sexual history helps select appropriate tests and partner care. It should be taken privately, respectfully and without assumptions or judgement. The clinician also checks for symptoms suggesting ectopic pregnancy, appendicitis, ovarian torsion, sepsis or another emergency. Abdominal and pelvic examination The clinician examines the abdomen for tenderness, guarding, swelling and signs of severe illness. A speculum examination may be offered to view the vagina and cervix and collect samples. Discharge, cervical bleeding or visible inflammation may provide supporting information. A bimanual examination uses gloved fingers in the vagina while the other hand gently examines the lower abdomen. Tenderness when the cervix moves, tenderness around the womb or tenderness near the ovaries can support PID. None of these findings confirms the diagnosis by itself. The examination requires consent. The person can ask questions, request a chaperone and ask the clinician to stop at any time. STI tests Samples are usually tested for chlamydia and gonorrhoea using a nucleic acid amplification test. Depending on the situation, a vaginal or cervical swab or urine sample may be used. Mycoplasma genitalium testing is recommended for people with signs and symptoms suggesting PID, although local availability may vary. Testing for HIV and syphilis is usually offered because a possible STI provides an opportunity for broader sexual health screening. A positive result identifies an infection that may have contributed to PID. A negative result does not exclude infection elsewhere in the upper reproductive tract. Antibiotics should not be delayed until these results return when the working diagnosis is PID. Other tests and imaging A pregnancy test helps identify pregnancy related diagnoses and guides antibiotic selection. Blood tests may assess inflammation, anaemia, kidney function or severe infection. Normal inflammatory markers do not reliably exclude mild PID. An ultrasound scan can identify an ectopic pregnancy, ovarian cyst, abscess or another pelvic abnormality. A normal scan does not exclude uncomplicated PID. CT or MRI may be used when the diagnosis remains uncertain or a complication is suspected. Laparoscopy allows direct examination of the pelvis but requires an operation. It is not routinely performed for every suspected case. No single blood test, swab, scan or examination finding confirms or excludes all PID. Why treatment often begins before results Delay increases the chance of continuing inflammation and possible long term tubal damage. The diagnosis is clinical because symptoms, examinations and tests all have limitations. Waiting for microbiology results may therefore expose the person to avoidable harm. Clinicians usually begin empirical treatment once the overall pattern makes PID sufficiently likely and pregnancy related emergencies have been assessed. Empirical treatment means treating the most likely condition before every result is known. It does not mean that the diagnosis is certain. The treatment covers several likely aerobic and anaerobic bacteria because PID is frequently polymicrobial. Results are reviewed later so the regimen can be changed when a resistant or specifically treatable organism is identified. Antibiotic treatment Mild or moderate PID is often treated without hospital admission. A common approach uses an antibiotic injection followed by two weeks of antibiotic tablets. More than one antibiotic is used because chlamydia, gonorrhoea, anaerobic bacteria and other organisms may be involved. The exact regimen depends on pregnancy, allergies, local resistance, recent antibiotic use and test results. Confirmed Mycoplasma genitalium may require specialist directed treatment. The full course should be completed even when pain and discharge improve early. Stopping treatment prematurely can allow infection or inflammation to persist. Common adverse effects include nausea, diarrhoea and thrush. Severe rash, breathing difficulty, jaundice or another serious reaction requires urgent advice. Antibiotics cannot treat ectopic pregnancy, ovarian torsion, appendicitis or established tubal scarring. Worsening symptoms require reassessment rather than simply changing tablets at home. When hospital treatment is considered Hospital assessment is considered when the person is very unwell, has severe pain or cannot keep oral medicines down. Admission may also be needed when an ectopic pregnancy, appendicitis, ovarian torsion or another surgical emergency cannot be excluded. Pregnancy, a tubo ovarian abscess, pelvic peritonitis or signs of sepsis increase the need for inpatient care. Failure to improve with oral antibiotics is another reason for hospital investigation and intravenous treatment. Surgery is not routine for uncomplicated PID. It may be needed to drain an abscess, manage rupture or treat an alternative surgical diagnosis. Reassessment after treatment begins Symptoms should begin improving within about 72 hours of starting appropriate treatment. A review at around 72 hours is particularly important when symptoms were moderate or severe. Failure to improve may indicate an abscess, resistant organism, incomplete medicine absorption, incorrect diagnosis or another complication. Further examination, imaging, intravenous treatment or surgery may then be required. Improvement does not remove the need to complete antibiotics and ensure that partner management has occurred. Partner notification and treatment Current and recent sexual partners may have chlamydia, gonorrhoea or another infection without symptoms. A sexual health service can help identify which partners should be contacted, tested and treated. The relevant period depends on the organism, symptoms and sexual history. Partners may be offered treatment before their results return because untreated infection can be passed back and can cause complications in the partner. Partner notification can often be completed confidentially without revealing the identity of the person diagnosed. The purpose is to provide care, prevent reinfection and reduce onward transmission. It is not to determine blame or prove when an infection was acquired. A positive STI result does not reliably establish which partner had the infection first because infections may remain asymptomatic for prolonged periods. Sex during and after treatment Avoid vaginal, anal and oral sex until the person with PID and relevant partners have completed treatment and symptoms have resolved. Following the sexual health team's advice reduces the chance of reinfection before antibiotics have worked fully. Condoms reduce transmission of chlamydia, gonorrhoea and several other STIs when used correctly. Condoms do not replace partner testing and treatment after PID has been diagnosed. Fertility complications Inflammation within the fallopian tubes can damage their lining and create scar tissue. Tubal scarring may make it harder for an egg and sperm to meet. This can reduce fertility or cause tubal factor infertility. Most people treated for PID do not become infertile. The risk rises when treatment is delayed, disease is severe or PID occurs repeatedly. A future fertility problem should not be assumed from one diagnosis. Fertility assessment considers age, ovulation, tubal function, sperm and several other factors. Ectopic pregnancy risk A damaged fallopian tube may delay or block the movement of a fertilised egg towards the womb. The pregnancy may then implant within the tube. This is called a tubal ectopic pregnancy. A history of PID increases ectopic pregnancy risk but does not mean every later pregnancy will be ectopic. Anyone with previous PID who becomes pregnant should seek prompt advice for pelvic pain, bleeding, shoulder tip pain, dizziness or fainting. Early pregnancy assessment may include blood tests and ultrasound when symptoms or history justify it. Chronic pelvic pain Some people develop pelvic pain that continues after the infection has been treated. Possible contributors include scarring, adhesions, altered nerve signalling, pelvic floor muscle changes and another condition such as endometriosis. Persistent pain does not necessarily mean that active infection remains. Repeated antibiotics are not appropriate without evidence of reinfection or ongoing bacterial disease. Assessment may involve gynaecology, pain management, physiotherapy, sexual health care or other services according to the pattern. Recurrent PID PID can occur again when a new STI is acquired or when a partner remains untreated. A previous episode may also make future symptoms and complications more likely because existing tubal damage remains. Repeat infection increases the risk of fertility problems, ectopic pregnancy and chronic pelvic pain. Condom use, STI testing, partner treatment and completing antibiotics reduce preventable recurrence. Preventing PID There is no single test or vaccine that prevents every cause of PID. Condoms reduce the chance of acquiring chlamydia, gonorrhoea and several other sexually transmitted infections. Regular STI testing is appropriate when there are new or multiple partners, a partner has an STI, or a sexual health service recommends screening. Prompt treatment of chlamydia and gonorrhoea reduces the opportunity for infection to ascend into the upper reproductive tract. People having an intrauterine device fitted may be offered STI risk assessment or testing. Routine preventive antibiotics are not required for everyone. Confidentiality and stigma PID is a medical condition and should not be used to make assumptions about behaviour, fidelity or personal responsibility. Some cases are linked to an STI, while others involve bacteria normally found in the vagina or follow a reproductive procedure. Sexual health clinics provide confidential assessment, testing, treatment and partner notification support. Seeking care early protects health and future reproductive choices. Embarrassment or fear of judgement should not delay assessment. What this lesson should not be used for This lesson cannot diagnose PID from pelvic pain, discharge or an STI test alone. It cannot exclude ectopic pregnancy, appendicitis, ovarian torsion or another emergency. Do not use it to choose antibiotics, treat a partner informally or decide whether an intrauterine device should be removed. Seek urgent assessment for suspected PID because early empirical treatment can reduce the risk of complications.

PID is an ascending infection and inflammatory condition affecting the upper reproductive tract. It may be severe, mild or asymptomatic, and negative STI tests do not exclude it. Because delayed treatment increases the risk of tubal damage, clinicians often start broad spectrum antibiotics before every result is available and arrange confidential partner care.