Pelvic inflammatory disease

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Pelvic inflammatory disease is managed as a clinical syndrome because upper-tract inflammation is difficult to sample and may already be present after organisms disappear from the cervix. Recent lower abdominal or pelvic pain plus cervical-motion, uterine or adnexal tenderness creates a deliberately low treatment threshold once pregnancy-related and surgical emergencies have been assessed.

The sexual-health consultation should define anatomy, exposure and consequence. Ask about discharge, postcoital or intermenstrual bleeding and dyspareunia, but also pregnancy possibility, contraception, safeguarding, genital procedures, analgesic needs and whether treatment and confidential partner notification are practical. Chlamydia and gonorrhoea matter, while anaerobic and other vaginal organisms justify broad cover when NAAT is negative.

No normal result is a stand-alone exit. Normal inflammatory markers do not exclude mild disease, a negative cervical NAAT does not exclude an earlier ascending infection, and a normal ultrasound does not exclude endometritis or salpingitis. Ultrasound instead helps when the question is ectopic pregnancy, torsion, pyosalpinx, tubo-ovarian abscess or another focal pelvic condition.

A stable outpatient receives ceftriaxone 1 g intramuscularly once, doxycycline 100 mg twice daily and metronidazole 400 mg twice daily for 14 days. Pregnancy, sepsis, vomiting, abscess, severe illness, diagnostic uncertainty or a poor 72-hour response moves care into gynaecology and the intravenous pathway; a collection may need drainage or surgery rather than repeated antimicrobial escalation.

Follow-up joins short-term response to future reproductive health. Results must alter index and partner care, contraception should remain effective through any device decision, and recurrence prevention should be discussed without blame. Persistent pain, dyspareunia or fertility concerns after infection warrant assessment rather than serial empirical courses.

Key points

Ask about pain onset, bleeding, last menstrual period, pregnancy possibility, contraception, recent procedures, genital symptoms and exposure; then test pregnancy before accepting an uncomplicated PID label.
Offer empirical treatment for recent pelvic pain with cervical-motion, uterine or adnexal tenderness when no stronger diagnosis explains the presentation; mild disease has no reliable exclusion test.
Collect vaginal or cervical chlamydia and gonorrhoea NAAT and relevant extragenital samples, but remember that a negative lower-tract test does not clear upper-tract infection.
For stable outpatient care give ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg twice daily and metronidazole 400 mg twice daily for 14 days.
Admit for pregnancy, sepsis, severe pain, vomiting, tubo-ovarian abscess, inability to follow oral treatment, uncertain surgical diagnosis or failure to improve as an outpatient.
Discuss an intrauterine device in the context of response, contraceptive goals and pregnancy risk; evidence does not justify an automatic fixed-time removal rule.
Trace contacts from the six months before symptoms, modified by the sexual history, and apply the confirmed-organism or no-organism partner treatment rules while maintaining broad index care.
Book review within 72 hours and give return instructions for collapse, pregnancy symptoms, increasing focal pain, fever or vomiting; antibiotics without planned reassessment are incomplete care.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Exposure-linked cervical infection

Chlamydia or gonorrhoea may move from the lower tract into the uterus and tubes; detecting either organism changes partner treatment even though index therapy remains broad.

Mixed upper-tract microbiology

Anaerobes and other organisms from vaginal communities commonly contribute, which explains metronidazole and why a negative STI NAAT does not make the syndrome non-infectious.

Ascent around uterine events

Instrumentation, pregnancy-related events or the period around IUD insertion may facilitate movement through the cervix; the current assessment still needs infection exposure, pregnancy and contraceptive context.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Movement beyond the cervix
Organisms and inflammation extend through endometrium into fallopian tubes, ovaries or pelvic peritoneum, so cervical sampling can be negative after upper-tract injury has begun.
2
Tubal transport damage
Acute inflammation injures cilia and healing lays down fibrosis. The later concern is impaired gamete or embryo transport, linking timely treatment and reinfection prevention to fertility and ectopic risk.
3
Organised adnexal infection
Tube, ovary and nearby tissues can wall off pus as a complex collection; fever or pain may persist until drainage or surgery supplies source control.
4
Peritoneal extension to the liver capsule
Inflammation may reach the perihepatic surface and cause pleuritic right upper-quadrant pain, while gallbladder and other abdominal disease remain active alternatives.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Low-threshold pelvic syndrome

Recent bilateral or diffuse pelvic pain with cervical-motion, uterine or adnexal tenderness supports treatment after the immediate pregnancy and surgical screen, even when fever and discharge are absent.

Cervicitis clues

Mucopurulent discharge, friability and intermenstrual or postcoital bleeding increase the likelihood of an ascending sexually associated infection and guide lower-tract sampling.

Pregnancy emergency patternRed flag

A late period or positive test with unilateral pain, bleeding, shoulder-tip pain, dizziness or collapse needs immediate early-pregnancy assessment before outpatient PID care.

Collection or severe infectionRed flag

High fever, persistent vomiting, peritoneal signs, focal adnexal fullness or a palpable mass makes tubo-ovarian abscess, rupture or another complicated process more likely.

Perihepatitis context

Sharp right upper-quadrant pain that moves with breathing can accompany the pelvic syndrome, but examination and tests must still address gallbladder, liver, bowel and thoracic causes.

Failure at 72 hoursRed flag

Little improvement after three days is a diagnostic event: revisit pregnancy, adherence, antimicrobial susceptibility, abscess, torsion, appendicitis and the need for inpatient care.

Red flags requiring action

Treat pelvic pain plus pregnancy, bleeding, syncope or shoulder-tip pain as an ectopic-pregnancy pathway until urgent assessment localises the pregnancy.
Admit when haemodynamics, fever, vomiting, peritonism or pain severity make oral outpatient treatment unsafe.
Image and involve gynaecology when focal adnexal tenderness, a mass or continuing fever raises tubo-ovarian abscess or torsion.
Assess hepatobiliary, pleural and abdominal alternatives as well as perihepatitis when right upper-quadrant pain accompanies the pelvic syndrome.
A patient not clearly better within 72 hours needs repeat diagnosis, adherence and microbiology review, pelvic imaging and possible source control.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Immediate pregnancy testing and localisation when indicatedFirst step
Why
Detect the ectopic-pregnancy pathway and adapt medicines, imaging and admission.
Interpretation and limitations
Any positive or uncertain result with pelvic pain requires urgent early-pregnancy assessment; use serum hCG and transvaginal ultrasound according to that pathway.
02
Consent-based abdominal, speculum and bimanual examination
Why
Find tenderness that crosses the empirical-treatment threshold and identify bleeding, cervicitis, mass or another genital source.
Interpretation and limitations
Cervical-motion, uterine or adnexal tenderness supports PID but is not specific. Severe pain, instability or a pregnancy concern takes precedence over completing a routine examination.
03
Chlamydia and gonorrhoea NAAT from exposed anatomy
Why
Identify organisms that change index follow-up and partner therapy.
Interpretation and limitations
Use vaginal or cervical sampling plus rectal or pharyngeal sites when exposed. Negative lower-tract NAAT cannot exclude established upper-tract disease.
04
Gonococcal culture before treatment where feasible
Why
Recover an isolate for susceptibility and enable organism-specific follow-up.
Interpretation and limitations
Take culture from relevant sites when gonorrhoea is suspected or NAAT is positive, but never defer the indicated ceftriaxone-containing PID regimen.
05
Severity blood tests and cultures
Why
Support admission, resuscitation and monitoring when systemic illness or abscess is plausible.
Interpretation and limitations
Use full blood count, CRP, renal and liver tests and blood cultures according to severity. Normal markers do not rule out mild PID.
06
Transvaginal ultrasound
Why
Answer a focal question about pregnancy location, torsion, pyosalpinx, collection or an alternative pelvic lesion.
Interpretation and limitations
Prioritise it for pregnancy, severe unilateral pain, mass, fever or poor response. A normal image cannot dismiss uncomplicated clinical PID.
07
Wider sexual-health tests and safeguarding assessment
Why
Address HIV, syphilis, M. genitalium where relevant, exposure-window retesting, coercion and barriers to partner care.
Interpretation and limitations
Use the result to refine index and partner management without withdrawing the broad PID course solely because one pathogen is absent.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Ectopic pregnancy

A pregnancy result, timing of the last period, unilateral pain, bleeding, dizziness or shoulder-tip pain redirects the encounter to urgent hCG and ultrasound localisation.

Ovarian torsion or cyst event

Abrupt focal pain, vomiting or an adnexal mass requires urgent gynaecology because torsion, cyst haemorrhage or rupture cannot wait for an antibiotic response.

Appendicitis or other abdominal surgery

Migratory pain, bowel symptoms and localised peritoneal findings may overlap with PID; surgical review is appropriate when the distribution or progression does not fit the pelvic syndrome.

Endometriosis, bladder or bowel pain

A cyclical, chronic or recurrent pattern with repeatedly negative infection assessment prompts a structured non-infective evaluation instead of serial empirical PID courses.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01FIRST CONTACTExclude danger and cross the clinical treatment thresholdFirst stepRecent pelvic pain is accompanied by genital symptoms, exposure risk or pelvic tenderness.

1Record observations, pain pattern, last menstrual period, pregnancy possibility, contraception, bleeding and collapse symptoms before routine syndrome work.
2Perform pregnancy testing and arrange urgent gynaecology or surgical assessment for positive pregnancy, focal severe pain, peritonism, sepsis or mass.
3With consent, obtain pelvic findings, vaginal or cervical NAAT and relevant culture and extragenital samples, without waiting for results once clinical PID is likely.
4Document why outpatient care is safe or which admission criterion has redirected the pathway.

02OUTPATIENTTreat broadly and make the 72-hour review realPID is clinically likely, observations are stable and pregnancy, abscess and surgical emergencies are not driving admission.

1Give ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg twice daily and metronidazole 400 mg twice daily for 14 days.
2Explain completion of all three components, likely adverse effects, analgesia, abstinence, return symptoms and how the patient will receive confidential results.
3Preserve effective contraception and discuss an IUD decision in relation to clinical response, removal wishes, pregnancy risk and possible emergency contraception.
4EscalationReview within 72 hours; escalate worsening or absent improvement to repeat diagnosis, imaging and gynaecology rather than simply extending the same tablets.

03COMPLICATEDUse inpatient therapy and seek source controlPregnancy, sepsis, vomiting, severe illness, tubo-ovarian abscess, an uncertain surgical diagnosis or inadequate outpatient response is present.

1Resuscitate as required, involve gynaecology, collect cultures and pregnancy-related tests and arrange urgent targeted imaging.
2Start ceftriaxone 2 g intravenously daily plus doxycycline 100 mg twice daily, then complete 14 days with doxycycline and metronidazole after improvement.
3For persistent fever, rupture concern or a tubo-ovarian collection, decide with gynaecology whether image-guided drainage or surgery is required.
4Include analgesia, hydration, thromboprophylaxis, contraception, safeguarding and practical adherence in the admission plan.

04PARTNERSLink index results to confidential contact carePID has been diagnosed or treated empirically as a sexually associated upper-tract syndrome.

1Offer chlamydia, gonorrhoea, HIV and syphilis testing and use gonococcal culture and M. genitalium testing when indicated.
2Trace contacts from the six months before symptom onset, adjusted to the sexual history; offer current male partners chlamydia and gonorrhoea screening and other recent partners screening.
3Treat partners for gonorrhoea or chlamydia confirmed in the index patient; when index M. genitalium is confirmed, test partners and treat positives concurrently; if none is identified, offer male partners broad empirical cover such as doxycycline 100 mg twice daily for seven days.
4Maintain abstinence until patient and partners complete treatment and the required interval, then address retesting, contraception, persistent pain and fertility concerns.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

The complete outpatient combination for gonorrhoea, chlamydia, anaerobic and other likely upper-tract organisms.

Ceftriaxone, doxycycline and metronidazole

Give ceftriaxone 1 g intramuscularly once, doxycycline 100 mg orally twice daily for 14 days and metronidazole 400 mg orally twice daily for 14 days.

Check pregnancy and severe beta-lactam allergy; explain completion, doxycycline oesophageal and photosensitivity precautions, and formulation-specific metronidazole interaction advice.

The initial inpatient combination for severe or otherwise non-outpatient PID, followed by completion therapy after clinical improvement.

Ceftriaxone plus doxycycline inpatient regimen

Give ceftriaxone 2 g intravenously once daily plus doxycycline 100 mg orally or intravenously twice daily until improvement, then complete 14 days with doxycycline and metronidazole.

Coordinate pregnancy or major allergy with specialists, monitor organ function as severity requires and ensure metronidazole is included in the oral completion phase.

A specialist inpatient alternative when the usual cephalosporin route is unsuitable.

Clindamycin plus gentamicin alternative

Give clindamycin 900 mg intravenously three times daily plus gentamicin using the local weight-based intravenous protocol, then step down with specialist guidance.

Use specialist dosing and monitoring: check renal function and gentamicin levels, assess auditory risk, watch for C. difficile diarrhoea and specify the oral step-down course.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Tubo-ovarian abscess and sepsis

A walled collection can maintain fever and focal pain, rupture into the peritoneum or cause systemic illness; antibiotics may need image-guided or operative source control.

Tubal-factor infertility

Ciliary loss, luminal narrowing and adhesions may reduce fertility, with cumulative injury more likely after delayed or repeated episodes.

Future ectopic implantation

Scarred or poorly functioning tubes can slow embryo transport, so later pregnancy pain should be assessed promptly even after the original infection has resolved.

Persistent pelvic pain and dyspareunia

Adhesions, residual inflammation and pain sensitisation may continue after microbial cure; follow-up should validate symptoms and seek a new diagnosis rather than repeat antibiotics automatically.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Arrange a named review within 72 hours and compare pain, pelvic tenderness, temperature, vomiting, oral intake and functional recovery with baseline.
Escalate collapse symptoms, increasing focal or unilateral pain, peritonism, fever, vomiting or a new pregnancy concern immediately rather than waiting for the planned review.
Act promptly on chlamydia and gonorrhoea NAAT, gonococcal culture and M. genitalium results; apply the confirmed-organism or no-organism contact rule without narrowing the patient’s completed broad PID course inappropriately.
Maintain a six-month tracing frame modified by sexual history, document confidential referral, and confirm abstinence until index and partners have finished treatment and the required interval.
For admitted or abscess disease, follow observations, inflammation, renal function, imaging and the response to any drainage according to severity.
Record contraception, any IUD discussion, last menstrual period, pregnancy result, emergency-contraception needs, safeguarding and blood-borne-virus prevention advice.
Route ongoing pain, dyspareunia, recurrence or fertility concern to sexual health or gynaecology for a fresh diagnosis and reproductive review rather than automatic repeat antibiotics.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Treat the syndrome while testing the cause

Lower-tract microbiology refines partner and follow-up care, but cannot safely postpone or exclude treatment of clinically likely upper-tract inflammation.

Pregnancy testing changes the entire decision tree

It identifies both a life-threatening competing diagnosis and a context in which antimicrobial choice, imaging and admission need specialist coordination.

Ultrasound should answer a question

Use it to locate pregnancy, torsion, pyosalpinx, abscess or another focal lesion; do not use a normal scan as proof that mild PID is absent.

Metronidazole is part of broad index therapy

Anaerobic and polymicrobial involvement persists even when chlamydia and gonorrhoea tests are negative, so the outpatient three-drug course is intentional.

An IUD discussion includes contraceptive consequence

Removal is not an automatic clock-based intervention; response, patient preference, ongoing pregnancy prevention and any emergency-contraception need belong in the decision.

The 72-hour review is a safety test

Non-response raises missed pregnancy or surgery, poor adherence, resistance, abscess and source-control questions rather than merely the need for longer treatment.

Partner care protects future tubes

Confidential notification, organism-linked treatment and reinfection prevention are part of preventing further inflammatory injury, not an optional social add-on.

11Common pitfallsFrequent interpretation and management errors.

01
Do not begin a routine PID pathway before checking pregnancy and immediate ectopic or surgical danger.
02
Do not wait for a positive NAAT, raised CRP or abnormal ultrasound when the clinical treatment threshold has been met.
03
Do not stop considering PID because lower-tract chlamydia and gonorrhoea tests are negative.
04
Do not omit metronidazole from the standard outpatient course or shorten the 14-day components without a justified alternative pathway.
05
Do not remove an IUD reflexively without discussing contraception, pregnancy risk and response with the patient.
06
Do not finish care without a 72-hour response check, a results route and confidential partner management.

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