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Contents
Abstract
- Pelvic inflammatory disease (PID) is an inflammatory condition caused by the spread of bacteria from the lower to the upper reproductive tracts of the female. It can cause pain, vaginal discharge, abnormal bleeding and reduced fertility. Complications include perihepatitis (inflammation of the covering of the liver) and peritonitis (inflammation of the lining of the abdomen).
- The infection can be caused by a sexually transmitted infection (STI), such as chlamydia or gonorrhoea, or by vaginal flora (the bacteria that normally live in the vagina). In some cases no organism is found. Every patient with suspected PID should be offered testing for STIs. A negative result does not rule out PID, and treatment should not wait for the results.
- It is treated with pain relief and antibiotics, started as soon as PID is suspected rather than after test results. Current and recent sexual partners (within the last 6 months) should also be advised to attend a sexual health service for screening and treatment. This is called contact tracing (finding and informing people who may have been exposed to the infection).
Core
What is Pelvic Inflammatory Disease?
Pelvic inflammatory disease (PID) is a condition caused by the spread of infection from the lower reproductive tract to the upper reproductive tract of the female. This means that the symptoms depend on how far the infection has spread. Not everyone develops all of them, and some women have none.
Initially the vaginal infection spreads to the cervix (the neck of the womb). This causes inflammation and tenderness, which can cause symptoms such as deep dyspareunia (pain felt deep inside during sex) and possible post-coital bleeding (bleeding after sex). Cervical inflammation can also lead to cervical discharge, which can change the vaginal discharge.
The infection can then spread into the uterus, causing endometritis (inflammation of the lining of the uterus). This can lead to menstrual irregularity, such as bleeding between periods (intermenstrual bleeding), as well as heavy and painful periods.
If the infection spreads into the Fallopian tubes, it causes salpingitis (inflammation of the Fallopian tubes, the tubes that carry eggs from the ovaries to the uterus). This leads to abdominal pain. This inflammation can damage the Fallopian tubes by causing stricture formation (scarring that narrows or blocks the tube). It can also cause reduced function of the cilia (tiny hair-like projections lining the tube), which normally waft the ovum towards the uterus. This can lead to infertility and an increased risk of tubal ectopic pregnancy (a pregnancy that implants in the tube instead of the uterus). There is also a risk of developing a tubo-ovarian abscess (a swelling filled with pus in a Fallopian tube and ovary).
The ends of the Fallopian tubes are open into the peritoneal cavity (the space inside the abdomen that holds the bowel). Infection can therefore spread out of the tube and into this space. This can cause intra-abdominal complications such as peritonitis (inflammation of the lining of the abdomen) and perihepatitis (inflammation of the covering of the liver, known as Fitz-Hugh-Curtis syndrome).
Pelvic inflammatory disease is commonly, but not always, caused by an untreated or missed sexually transmitted infection (STI). The risk of missing STIs in women is relatively high, as many STIs are asymptomatic (without symptoms) in women. This means that two things are key to detecting infection. One is partner notification (telling recent sexual partners that they may have been exposed to an infection). The other is attending a sexual health clinic after unprotected sexual intercourse (UPSI).
- Chlamydia trachomatis (chlamydia infection) is the most commonly identified cause, found in about 14 to 35% of cases.
- Neisseria gonorrhoeae (gonorrhoea infection), found in about 2 to 3% of cases.
- Mycoplasma genitalium (a sexually transmitted bacterium) may be associated with 10 to 25% of cases of PID and cervicitis (inflammation of the cervix) in women.
- Not all cases are due to STIs. Normal vaginal flora (the bacteria that normally live in the vagina) can also be responsible, and mixed infections are common.
- In some cases no causative organism is found. This is known as pathogen-negative PID, and it is also common.
Risk factors for PID are mainly in two groups:
- Factors that increase the likelihood of contracting an initial infection:
- Young age (under 25 years)
- Recent change in sexual partners
- History of multiple sexual partners
- Young age at first intercourse (under 15 years)
- Not using barrier contraception (such as condoms)
- Previous PID, or a history of an STI in the patient or her partner
- Factors that increase the chances of an existing vaginal infection ascending to the upper reproductive tract:
- Termination of pregnancy
- Insertion of intrauterine device (IUD) or intrauterine system (IUS), particularly in the weeks following insertion
- Hysterosalpingography (imaging of the womb and Fallopian tubes using contrast and X-rays)
- Hysteroscopy (looking inside the womb with a thin telescope)
- In vitro fertilisation (IVF) or intrauterine insemination (placing sperm directly into the uterus)
PID can present with any, all or none of the following symptoms:
- Pelvic or lower abdominal pain, commonly bilateral.
- Deep dyspareunia (pain on deep penetration of the vagina).
- Abnormal vaginal bleeding. This can be intermenstrual bleeding (between periods), post-coital bleeding (after sex), breakthrough bleeding (unexpected bleeding while on hormonal contraception) or heavy periods. It may be secondary to cervicitis (inflammation of the cervix) or endometritis (inflammation of the lining of the uterus).
- Abnormal vaginal or cervical discharge, which may be mucopurulent (a mixture of mucus and pus).
- Symptoms affecting the whole body, such as fever (which may be absent), nausea or vomiting, and feeling generally unwell (malaise). These may suggest severe infection or a complication.
- Pain in the right upper abdomen or the right shoulder, which may be due to perihepatitis.
- Due to the possible involvement of the Fallopian tubes, PID can also present with reduced fertility. This is because the inflammation can lead to stricture formation, or ciliary dysfunction (meaning the egg is not effectively wafted towards the uterus).
Some women have only mild symptoms or none, so the condition can easily be missed. Doctors therefore need a low threshold for suspecting PID in a sexually active woman with pelvic or lower abdominal pain.
Examination and Investigations
In any woman presenting with possible PID, it is important to perform an abdominal and a vaginal examination, with a chaperone (someone else in the room during the examination, such as a nurse or a trained member of staff). This may demonstrate lower abdominal tenderness. Bimanual examination (one hand inside the vagina and the other on the lower abdomen) may also show adnexal tenderness (tenderness over the Fallopian tubes and ovaries, beside the uterus), cervical motion tenderness (pain when the cervix is gently moved from side to side) or uterine tenderness (pain when the uterus is pressed). A speculum examination (using an instrument that holds the vaginal walls apart to show the cervix) may show pus-like discharge or a cervix that bleeds easily (cervical friability).
PID is diagnosed clinically, from the symptoms and examination findings. Investigations help to exclude other causes and to identify the infection, but treatment should not be delayed while waiting for the results.
- Pregnancy Test - this will help to exclude ectopic pregnancy, which may be causing similar symptoms.
- STI Screen - vaginal or endocervical swabs (endocervical means from inside the cervix) with NAAT (nucleic acid amplification test, which detects the genetic material of bacteria) for chlamydia and gonorrhoea. This helps to identify an infection, and a positive result makes PID more likely. It is important to remember though that not all PID is caused by an STI, so negative swabs do not rule out PID. Testing for Mycoplasma genitalium (a sexually transmitted bacterium that can cause PID) should also be considered where it is available, because a positive result can change the choice of antibiotic. HIV, hepatitis and syphilis blood tests can be done as part of an STI screen.
- Examination under a microscope for pus cells (white blood cells that gather at a site of infection) on a smear of vaginal cells, where equipment and expertise are available. Pus cells may be seen in PID or in infection of the lower genital tract, so they do not confirm PID. If pus cells are absent, PID is unlikely.
- Blood Tests - these blood tests can support a possible diagnosis of PID if the results are raised, but a raised result can have other causes, so it does not confirm PID:
- C-reactive protein (CRP, a marker of inflammation)
- Leucocyte count (white blood cell count)
- Erythrocyte sedimentation rate (ESR, another marker of inflammation)
The most important things to think about when treating PID are analgesia (pain relief), antibiotics to treat the infection, and contact tracing. Contact tracing means finding and informing recent sexual partners so that they can be screened and treated.
- Analgesia: paracetamol and/or ibuprofen can be used if there are no contraindications.
- Antibiotics are started as soon as a working diagnosis of PID is made (that is, PID is the most likely diagnosis on the evidence so far), before test results are available. Ideally swabs for STI screening are taken before the first dose of antibiotics, but treatment does not wait for the tests to be arranged or for the results. The usual first-choice (first-line) course is a single intramuscular (into a muscle) injection of ceftriaxone, followed by doxycycline and metronidazole tablets for 14 days. If a swab is positive for Mycoplasma genitalium, moxifloxacin (a different antibiotic) tablets are used instead, for 14 days. The course is completed even if swabs are negative, to reduce the risk of long-term complications.
- Intrauterine device (IUD): if she has an IUD fitted, it can stay in place when symptoms are mild to moderate, provided she is improving within 48 to 72 hours of starting antibiotics. It is removed if she is not improving or if her symptoms are severe.
- Hospital admission is arranged urgently if:
- the patient is pregnant, or an ectopic pregnancy is suspected;
- there are severe systemic symptoms (symptoms affecting the whole body, such as fever or vomiting) or an adnexal mass (a lump in the Fallopian tube or ovary, beside the uterus), which suggest a complication such as a tubo-ovarian abscess or pelvic peritonitis;
- she is systemically unwell and the diagnosis is uncertain; or
- she cannot follow or tolerate treatment at home.
- Contact tracing: current and recent sexual partners (within the last 6 months) should attend a sexual health service for STI screening and treatment. The patient and all her partners should avoid all sex until each of them has finished antibiotic treatment and is free of symptoms.
- Review within 72 hours (depending on clinical judgement) to check the response to treatment and the swab results, and to advise on barrier contraception to reduce the risk of reinfection.
Primary Prevention (stopping the disease from starting) - prevention of STI contraction, e.g. sex and relationships education in schools, use of barrier contraception.
Secondary Prevention (finding and treating disease early, before symptoms appear) - screening for STIs when asymptomatic (without symptoms). In England, the National Chlamydia Screening Programme focuses on proactively offering chlamydia tests to young women without symptoms.
Tertiary Prevention (reducing the harm once disease is established) - prevention of the complications of PID through swift diagnosis and treatment, and treating any partners to avoid reinfection.
Edited by: Dr. Ben Appleby
Reviewed by: Dr. Thomas Burnell and Dr. Marcus Judge
Quiz
- 4043
