Authors: Rachel Austin, Anu Mitra, Ursula Edirisinghe / Editor: Frances Balmer / Codes: CAP26, HAP31, ObC12, ObP1, ObP5, SeC3, SLO1 / Published: 01/12/2021
Pelvic inflammatory disease (PID) is a common presentation to primary and secondary care. Sequelae can include infertility, chronic pelvic pain and an increased risk of ectopic pregnancy. Early recognition and treatment can reduce these complications1. This learning session will cover the pathophysiology, assessment and treatment of PID and equip you with the knowledge and confidence to manage this important presentation in the Emergency Department.
What is pelvic inflammatory disease?
PID is a general term for an infection of the upper genital tract (involving the endometrium, fallopian tubes or ovaries). It can lead to local abscess formation or pelvic peritonitis.2
The most common cause of PID is a sexually-transmitted infection which has spread from the lower genital tract. Common causative organisms include:
- Chlamydia trachomatis (14-35% cases)
- Neisseria gonorrhoeae (2-3% cases)
- Mycoplasma genitalium
PID can also be caused by normal vaginal flora which migrate to the upper genital tract4.
Often no pathogen is identified.
Learning bite: Pathogen negative PID is common.
What are the risk factors for developing PID?
Risk factors for PID are:
- Young age
- In general practice
,PID is most common in women aged 20-24 years, but incidence has been falling in this demographic group. The most common cause is a sexually transmitted infection.
- In the hospital setting, PID is most common in women aged 35-44 years and incidence is relatively stable in this group. The causative organism is less likely to be sexually transmitted.
- In general practice
- Multiple sexual partners
- New recent sexual partner(s) in the last 3 months
- History of sexually transmitted infection (STI) in the patient or their partner(s)
- Not using barrier contraception
- Recent gynaecological procedures which cause disruption of the endocervical barrier and translocate bacteria into the upper genital tract such as:
- termination of pregnancy
- intrauterine device (IUD) insertion in the last 4-6wks
- in vitro fertilisation3
What are the complications of PID?
Early complications of PID include:
- Abscess formation
- Fitz-Hugh-Curtis syndrome. Infection spreads to the liver capsule causing peri-hepatitis and right upper quadrant pain. This is a rare complication associated with Chlamydia trachomatis.
Long term complications of PID due to scarring and adhesion formation include:
- Chronic pelvic pain
- Ectopic pregnancy
More severe and recurrent infections increase the risk of complications. Early treatment can reduce the risk of infertility.5
Learning bite: Early treatment can reduce the risk of infertility, chronic pain and ectopic pregnancy.
How should I assess suspected PID?
The following symptoms in the history suggest PID:
- Lower abdominal or pelvic pain, most commonly bilateral but sometimes unilateral
- Deep dyspareunia
- Abnormal vaginal discharge, which is usually purulent
- Abnormal vaginal bleeding, most commonly post-coital or menorrhagia
- Fever (although temperature often normal)
The following findings on examination are suggestive of PID:
- Lower abdominal tenderness
- Adnexal or uterine tenderness or cervical excitation on bimanual examination
- Abnormal discharge on speculum examination2, 4
PID can be asymptomatic. Even when present, signs and symptoms have low sensitivity and specificity so have a low threshold for diagnosis and empirical treatment.
How should I investigate suspected PID?
Consider the following investigations:
- Pregnancy test to exclude ectopic pregnancy
- Bloods tests
- FBC, U&Es, CRP
- Blood cultures if febrile and systemically unwell
- Consider testing for HIV or syphilis with consent if risk factors present
- Swab for STIs
- Endocervical swab with nucleic acid amplification test (NAAT) for Chlamydia and Gonorrhoea
- High vaginal swab: for bacterial vaginosis and Trichomonas
- First catch urine is an alternative method of testing for STIs although this is less sensitive
- Ultrasound scan can be considered if an abscess, appendicitis or ovarian cyst are suspected
- MRI or CT are not recommended to assess PID but may be required to exclude differential diagnoses2,4
Learning bite: any woman of child-bearing age with abdominal pain must have a pregnancy test to rule out ectopic pregnancy
Which other differential diagnoses should be considered?
The differential diagnoses are listed below. The most common mimics are appendicitis or ectopic pregnancy.
- Gynaecological causes:
- Ectopic pregnancy
- Ruptured ovarian cyst
- Ovarian torsion
- Mittelschmerz pain
- Gastrointestinal causes:
- Cervical excitation occurs in 25% women with appendicitis
- Irritable bowel syndrome
- Diverticular disease
- Urinary Tract Infection
- Functional pain 2,4,6
How do I treat PID?
A low threshold for starting empirical antibiotics for PID is recommended, due to the lack of sensitive or specific signs and symptoms, the severity of the complications, and the need to start treatment as early as possible.
Empirical treatment should be offered to any sexually active woman with new onset lower abdominal pain with bimanual tenderness in whom no other cause has been identified. Ideally swabs should be taken before antibiotics are commenced but treatment should not be delayed to wait for test results or a sexual health clinic appointment as this could increase the risk of complications.
Identify high risk patients requiring admission
Most patients can be effectively managed as outpatients. Inpatient admission for observation, intravenous antibiotics, further investigation and potential surgical review should be considered in the following cases:
- Patients who are systemically unwell or septic
- Patients who are unable to tolerate oral antibiotics
- Lack of response to oral antibiotics
- Suspected tubo-ovarian abscess
- A surgical emergency cannot be excluded
- Pregnant women. PID is associated with an increased risk of maternal and foetal morbidity and pre-term delivery
First-line treatment for mild to moderate PID is a stat dose of intramuscular ceftriaxone 1g (single dose) followed by oral doxycycline 100mg BD and oral metronidazole 400mg BD for 14 days.
If intravenous therapy is needed the recommended first-line treatment is ceftriaxone 2g OD and doxycycline 100mg BD.
*Check with local guidelines as common causative organisms and sensitivities may vary.
Provide regular analgesia and anti-emetics as required.
Current partners should be offered a sexual health screen.
Advise contact tracing for sexual partners within six months of symptom onset.
Advise sexual abstinence until the treatment is complete (or use condoms if will not abstain).
An IUD can remain in situ initially, but if symptoms have not improved by 72 hours after starting antibiotics, then it should be removed. Emergency contraception may be required to protect against pregnancy.
Ask advice from a specialist if the patient is HIV positive. In mild to moderate cases, the empirical antibiotic is usually unchanged.
Patient information leaflets
Patient information leaflets are available from websites for the NHS, BASHH (British Association of Sexual Health and HIV) and RCOG (Royal College of Obstetricians and Gynaecologists).
Safety net patients prior to discharge. Consider arranging follow-up in the next 72hrs to ensure patients are improving. If a swab returns positive, repeat swabs are often necessary to ensure resolution.7
- RCOG. Management of Pelvic Inflammatory Disease. Guideline No.32. 2003. [Accessed 15/8/20].
- Ross J, Guaschino S, Cusini M, Jensen J. 2017 European guideline for the management of pelvic inflammatory disease. Int J STD AIDS. 2018 Feb;29(2):108-114.
- Dey, Pranab. Handbook of Cervical Cytology: Special Emphasis on Liquid-based Cytology. 2018.
- BASHH, 2018 United Kingdom National Guideline for the Management of Pelvic Inflammatory Disease. British Association for Sexual Health and HIV. 2018.
- Price M, Ades AE, Welton N et al. Pelvic inflammatory disease and salpingitis: incidence of primary and repeat episodes in England. Epidemiol Infect. 2017 Jan;145(1):208-215.
- Bhavsar AK, Gelner EJ, Shorma T. Common Questions About the Evaluation of Acute Pelvic Pain. Am Fam Physician. 2016 Jan 1;93(1):41-8.
- National Institute for Health and Care Excellence, Pelvic Inflammatory Disease. NICE CKS. (2019). [Accessed 15/8/20].