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← Obstetrics and gynaecology indexChapter sections
OverviewAetiologyPathophysiologyClinical features and red flagsInvestigationsDifferential diagnosisManagementComplicationsMonitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Pelvic inflammatory disease

Obstetrics and gynaecology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Exclude surgical and pregnancy emergencies

Haemodynamic instability, peritonism, severe systemic illness, pregnancy, a tubo-ovarian abscess or inability to tolerate oral treatment requires urgent hospital assessment rather than routine outpatient management.

Action: Check observations and hCG, assess for ectopic pregnancy and appendicitis, obtain cultures and imaging without delaying resuscitation, and involve acute gynaecology for parenteral antibiotics and source-control decisions.

Overview

Recognise and treat pelvic inflammatory disease at a deliberately low diagnostic threshold while excluding pregnancy emergencies, identifying severe disease and protecting reproductive health.

Pelvic inflammatory disease includes endometritis, salpingitis, oophoritis, pelvic peritonitis and tubo-ovarian abscess caused by organisms ascending from the lower genital tract. Chlamydia and gonorrhoea are important, but mixed vaginal anaerobes and other organisms mean a negative cervical STI test cannot exclude upper-tract inflammation. Because even mild or subclinical disease can damage tubes, clinical practice accepts some overtreatment in order to avoid delayed therapy.

Ask about onset and location of pelvic pain, abnormal or postcoital bleeding, discharge, deep dyspareunia, fever, urinary and bowel symptoms, vomiting, last menstrual period, pregnancy possibility, contraception, recent uterine instrumentation and sexual exposures. Establish severity and safeguarding context privately. Differentials include ectopic pregnancy, appendicitis, ovarian torsion or cyst accident, endometriosis, urinary infection, renal colic and gastrointestinal disease. Fitz-Hugh-Curtis perihepatitis can produce right-upper-quadrant pleuritic pain with otherwise subtle pelvic findings.

Practice

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Obstetrics and gynaecologyOriginal SBA

Treating a clinical PID syndrome

A 25-year-old has bilateral lower abdominal pain, cervical excitation and adnexal tenderness. Pregnancy testing is negative, she is systemically stable, and cervical NAAT results are pending. What should happen next?

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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • BASHH pelvic inflammatory disease guideline
  • RCOG pelvic inflammatory disease information
  • NHS pelvic inflammatory disease guidance
  • NICE ectopic pregnancy and miscarriage guidance

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
Record observations and examine the abdomen for focal tenderness, guarding and peritonism. With consent and a chaperone, speculum examination may show mucopus, contact bleeding or an alternative cause. Bimanual examination assesses cervical motion, uterine and adnexal tenderness or a mass. Tenderness is sensitive but not specific; its absence lowers probability but does not negate a compelling history. Avoid delaying antibiotics while awaiting ultrasound or microbiology when the clinical threshold is met.

Investigations support safety and causation. Perform hCG, chlamydia and gonorrhoea NAAT, gonococcal culture where possible, and HIV and syphilis testing according to risk. Urinalysis and blood tests help with alternatives and severity. Transvaginal ultrasound is valuable for abscess, hydrosalpinx, pregnancy localisation or another mass but can be normal in uncomplicated PID. Laparoscopy is not a routine diagnostic requirement. M. genitalium testing and resistance-guided treatment follow specialist or local pathways rather than indiscriminate empirical macrolides.

Stable mild-to-moderate disease is usually managed as an outpatient with ceftriaxone, doxycycline and metronidazole. This covers gonorrhoea, chlamydia and anaerobes. Admit for pregnancy, severe illness, abscess, diagnostic uncertainty involving a surgical emergency, inability to tolerate oral medication or failure of outpatient therapy. Pregnancy requires specialist parenteral selection because doxycycline is inappropriate. Fluoroquinolone alternatives are restricted by gonococcal resistance and the risk of serious persistent adverse effects, so should be used only within a justified specialist pathway.

Arrange review at 72 hours, not merely after the course. Improvement means falling pain, fever and tenderness; complete all 14 days even if symptoms settle early. Failure should prompt re-examination of adherence, vomiting, pregnancy, abscess, resistant or untreated infection and a non-PID diagnosis. Offer partner notification and treatment for chlamydia or gonorrhoea and follow the relevant lookback. Explain possible fertility, ectopic and chronic-pain consequences without suggesting that damage is inevitable, and provide an accessible route back for worsening symptoms.

Key points

  • PID is a clinical syndrome of upper-genital-tract inflammation; no single history, examination, swab or scan reliably rules it in or out.
  • Use a low treatment threshold when lower abdominal or pelvic pain coexists with cervical motion, uterine or adnexal tenderness and no better explanation.
  • Always check pregnancy because ectopic pregnancy can mimic PID, and remember that PID can coexist with an intrauterine or early unlocalised pregnancy.
  • Take chlamydia and gonorrhoea NAAT, gonococcal culture before antibiotics where possible, and consider M. genitalium testing under local specialist protocols; negative lower-tract tests do not exclude PID.
  • Outpatient treatment is ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg orally twice daily for 14 days plus metronidazole 400 mg orally twice daily for 14 days.
  • Review clinical response at 72 hours; lack of improvement triggers diagnostic reconsideration, pelvic imaging, parenteral therapy and possible surgical assessment.
  • Do not remove an intrauterine device automatically; consider removal if there is no improvement after 72 hours, balancing contraceptive needs and patient preference.

Aetiology

01

Sexually transmitted organisms

C. trachomatis and N. gonorrhoeae ascend from the cervix and remain important causes even when symptoms are mild.

02

Polymicrobial ascent

Anaerobes and organisms associated with vaginal dysbiosis contribute to endometrial and tubal inflammation, supporting broad combination antibiotic coverage.

03

Instrumentation-related entry

Recent uterine procedures can transiently facilitate ascent, although most PID is not caused by an established intrauterine device itself.

Pathophysiology

  1. 1
    Endocervical breach

    Pathogens traverse cervical defences and reach the endometrium, where local inflammation creates pain, bleeding and inflammatory exudate.

  2. 2
    Tubal inflammation

    Salpingitis damages ciliated epithelium, produces oedema and adhesions and can impair later ovum transport despite clinical recovery.

  3. 3
    Suppurative extension

    Unchecked infection can involve ovaries and adjacent structures, forming a tubo-ovarian abscess with risk of rupture and sepsis.

  4. 4
    Peritoneal irritation

    Pelvic inflammation produces cervical-motion tenderness and may extend along the peritoneum to the liver capsule in Fitz-Hugh-Curtis syndrome.

Clinical features and red flags

Minimum clinical pattern

Recent pelvic or lower abdominal pain with cervical motion, uterine or adnexal tenderness and no stronger alternative supports empirical PID treatment.

Supporting genital inflammation

Mucopurulent discharge, cervical friability, raised inflammatory markers or a positive chlamydia or gonorrhoea test increases diagnostic confidence but is not essential.

Tubo-ovarian abscess

High fever, systemic illness, marked adnexal tenderness or a complex adnexal mass suggests suppurative disease requiring admission, imaging and source-control planning.

Fitz-Hugh-Curtis syndrome

Sharp right-upper-quadrant pain from perihepatitis can accompany chlamydial or gonococcal PID and may mimic biliary or pulmonary disease.

Red flags requiring action

  • A positive pregnancy test with unilateral pain, bleeding, syncope, shoulder-tip pain or peritoneal signs requires urgent ectopic-pregnancy assessment.
  • Hypotension, tachycardia, high fever, rigors, vomiting, confusion or peritonism suggests sepsis, abscess rupture or another acute abdomen.
  • A complex adnexal mass with fever or marked tenderness raises concern for tubo-ovarian abscess and needs urgent specialist management.
  • Failure to improve within 72 hours of appropriate outpatient antibiotics requires reassessment, imaging and possible admission.

Investigations

  1. 01
    Urine or serum hCGFirst step
    Why
    Identify pregnancy and prioritise ectopic-pregnancy localisation before routine outpatient care.
    Interpretation and limitations
    A positive result with pain is an urgent early-pregnancy presentation; a negative test removes ectopic pregnancy but not ovarian, gastrointestinal or urinary emergencies.
  2. 02
    Chlamydia and gonorrhoea NAAT with gonococcal culture
    Why
    Identify treatable causes, support partner management and obtain gonococcal susceptibility.
    Interpretation and limitations
    A positive result supports the diagnosis, but a negative lower-tract sample cannot exclude upper-tract PID; take culture before ceftriaxone when feasible.
  3. 03
    Transvaginal pelvic ultrasound
    Why
    Detect tubo-ovarian abscess, hydrosalpinx, pregnancy pathology, torsion clues or another pelvic mass.
    Interpretation and limitations
    Thickened fluid-filled tubes or a complex inflammatory mass supports PID, while a normal scan is common in uncomplicated disease and must not delay treatment.
  4. 04
    Full blood count, CRP and renal or liver profile
    Why
    Assess inflammatory burden, organ function and safety for inpatient or parenteral treatment.
    Interpretation and limitations
    Raised markers support inflammation but normal results

Differential diagnosis

01

Ectopic pregnancy

Amenorrhoea, bleeding, unilateral pain or instability makes pregnancy testing and urgent localisation essential before attributing symptoms to PID.

02

Ovarian torsion or cyst

Sudden severe unilateral pain, vomiting or an adnexal mass points toward torsion or cyst accident requiring urgent imaging and surgery.

03

Appendicitis or bowel disease

Migratory right-sided pain, gastrointestinal symptoms or peritoneal signs may represent appendicitis, inflammatory bowel disease or diverticular pathology.

04

Urinary tract disease

Dysuria, flank pain, haematuria or urinary culture findings can indicate cystitis, pyelonephritis or renal colic, sometimes alongside an STI.

05

Endometriosis

Cyclical chronic pain and deep dyspareunia can mimic PID, but acute fever, mucopus and new tenderness favour infection.

Additional chapter-specific clues

Alternative acute abdomen

Abrupt unilateral pain, peritonism, positive hCG, gastrointestinal localisation or urinary colic features mandate parallel assessment for torsion, ectopic pregnancy, appendicitis or renal disease.

Management

01PresentationTreat at a safe clinical thresholdFirst stepPelvic pain is accompanied by cervical motion, uterine or adnexal tenderness without a better diagnosis.+
  1. 1Record observations, obtain hCG and assess peritonism, severe illness, pregnancy and acute-surgical alternatives before choosing setting of care.
  2. 2Collect site-appropriate NAAT and gonococcal culture, but begin broad empirical antibiotics immediately when PID is clinically likely.
  3. 3Give written completion, abstinence, partner and deterioration advice and arrange an active 72-hour review rather than open-ended follow-up.
02AdmissionEscalate severe or complicated diseaseEscalationThere is pregnancy, systemic illness, abscess, surgical uncertainty, oral intolerance or outpatient failure.+
  1. 1Involve acute gynaecology, start sepsis management when indicated and obtain ultrasound or cross-sectional imaging according to the differential.

Complications

01

Tubo-ovarian abscess

A walled-off inflammatory mass can rupture, cause sepsis or fail oral antibiotics, prompting drainage or operative management.

02

Tubal-factor infertility

Epithelial injury and adhesions impair fertilisation and transport, with risk increasing after repeated or severe episodes.

03

Ectopic pregnancy

Tubal scarring can delay embryo transport and increase the chance that a future pregnancy implants outside the uterus.

04

Chronic pelvic pain

Persistent inflammation, adhesions and sensitisation may produce long-term pelvic pain or deep dyspareunia after microbiological cure.

Monitoring and follow-up

  • Arrange direct review after 72 hours to document change in pain, temperature, abdominal findings and cervical or adnexal tenderness.
  • Confirm completion of all 14 treatment days and assess vomiting, adverse effects, missed doses and continued exposure before labelling therapy ineffective.
  • Track chlamydia or gonorrhoea partner outcomes and arrange organism-specific test of cure or reinfection testing where current guidance requires it.
  • Reassess an IUD only if clinical response is inadequate at 72 hours, with shared decision-making and alternative contraception discussed.
  • At later review, address ongoing pelvic pain, dyspareunia, menstrual disturbance or fertility concerns and refer according to symptoms rather than offering routine proof of tubal patency.

Special situations

Negative swabs do not exclude PID

Ascending organisms may no longer be detectable in the cervix, and mixed non-STI flora can cause upper-tract inflammation.

Ultrasound can be normal

Imaging is valuable for abscess and alternatives but lacks sensitivity for uncomplicated endometritis or salpingitis, so clinical treatment should not wait.

Review is part of treatment

The 72-hour reassessment detects abscess, diagnostic error, poor absorption and failing outpatient therapy before complications progress.

An IUD can usually remain

Immediate routine removal is unnecessary; lack of improvement after 72 hours creates the point for reconsideration and shared choice.

Mild disease still matters

Subtle symptoms do not guarantee limited tubal inflammation, which is why the recommended treatment threshold is intentionally low.

Common pitfalls

  1. 01

    Waiting for a positive chlamydia or gonorrhoea test before treating a compatible clinical syndrome.

  2. 02

    Using a normal pelvic ultrasound or normal CRP to rule out uncomplicated PID.

  3. 03

    Missing ectopic pregnancy, torsion or appendicitis because cervical tenderness is present.

  4. 04

    Omitting metronidazole from outpatient combination therapy without a documented patient-specific reason.

  5. 05

    Leaving review until the 14-day course ends instead of assessing response at 72 hours.

  6. 06

    Removing an intrauterine device automatically at diagnosis without considering early clinical response, contraception and patient preference.

  • Abstain from sex until the patient and relevant partners have completed treatment and symptoms have resolved, with partner care driven by identified or suspected STI.
    • Pregnancy, severe immunosuppression, unreliable oral absorption or inability to ensure follow-up lowers the threshold for inpatient care.
    do not
    exclude mild PID; abnormal organ function or sepsis physiology increases urgency and affects antibiotic selection.
  • 05
    HIV, syphilis and selected M. genitalium testing
    Why
    Detect co-infection and explain persistent or recurrent disease under a specialist protocol.
    Interpretation and limitations
    Reactive serology requires confirmatory care; M. genitalium results should be linked to resistance-aware treatment rather than empirical azithromycin escalation.
  • 2Use a recommended parenteral broad-spectrum regimen with pregnancy, allergy, organ function and microbiology considered by the treating team.
  • 3Drain or operate when abscess rupture, non-response or another surgical condition requires source control, then complete an adequate total course.
    • 03ReviewReassess response at 72 hoursOutpatient therapy has been started or an intrauterine device remains in place.+
    1. 1Confirm that pain, fever and pelvic tenderness are improving and that oral doses have been retained and taken correctly.
    2. 2AlternativeIf response is poor, repeat examination, reconsider pregnancy and alternative diagnoses, arrange imaging and move to inpatient or specialist management.
    3. 3AlternativeDiscuss IUD removal only when there is no clinical improvement after 72 hours, ensuring alternative contraception and the patient's preference are addressed.
    Key medicines and prescribing safety3 treatments · regimens, roles and cautions+
    Provides reliable current gonococcal coverage within a broad regimen for mild-to-moderate pelvic inflammatory disease.

    Ceftriaxone

    Give 1 g by intramuscular injection as one dose at the start of outpatient PID treatment.

    Check severe beta-lactam allergy and obtain gonococcal culture first when feasible, but do not delay treatment in clinically significant disease.

    Covers C. trachomatis and other susceptible organisms that contribute to upper-genital-tract infection.

    Doxycycline

    Take 100 mg orally twice daily for fourteen days as part of combination PID therapy.

    Avoid in pregnancy, counsel about oesophageal irritation and photosensitivity, separate interacting antacids and ensure the full course is completed.

    Extends coverage to anaerobes and also treats coexisting bacterial vaginosis within the PID regimen.

    Metronidazole

    Take 400 mg orally twice daily for fourteen days alongside ceftriaxone and doxycycline.

    Discuss gastrointestinal effects, metallic taste and relevant interactions, and review current product advice about alcohol rather than giving inconsistent instructions.