Overview
Pelvic Inflammatory Disease (PID)
1. Clinical Overview
Summary
Pelvic Inflammatory Disease (PID) is an infection of the upper female genital tract (Uterus, Fallopian tubes, Ovaries, Peritoneum) usually caused by ascending infection from the vagina/cervix. The most common causes are Chlamydia trachomatis and Neisseria gonorrhoeae, though many cases are polymicrobial. PID is a major cause of infertility (Due to tubal damage), ectopic pregnancy, and chronic pelvic pain. Risk factors include young age, multiple sexual partners, prior STIs, and IUD insertion (Within first 3 weeks). Patients present with lower abdominal/pelvic pain, deep dyspareunia, abnormal vaginal discharge, and cervical motion tenderness on examination. Diagnosis is primarily clinical (Low threshold to treat due to serious sequelae). Treatment is with broad-spectrum antibiotics covering Chlamydia, Gonorrhoea, and Anaerobes. Partner notification and treatment are essential. Complications include Tubo-Ovarian Abscess (TOA) and Fitz-Hugh-Curtis Syndrome (Perihepatitis). [1,2,3]
Clinical Pearls
"Low Threshold to Treat": Don't wait for definitive diagnosis. The consequences of untreated PID (Infertility, Ectopic) are severe. Treat empirically if suspected.
"Triple Threat: Chlamydia, Gonorrhoea, Anaerobes": Antibiotics must cover all three.
"Cervical Motion Tenderness = Chandelier Sign": Pain on moving the cervix during bimanual exam is classic for PID.
"Always Exclude Ectopic Pregnancy": Pregnancy test is mandatory. Ectopic is a differential and can coexist or mimic PID.
2. Epidemiology
Demographics
| Factor | Notes |
|---|---|
| Age | Most common in sexually active women aged 15-25 years. |
| Incidence | Common. ~1-2% of sexually active young women per year. |
| Asymptomatic PID | Subclinical PID is common (~70% of Chlamydia-associated PID may be asymptomatic). Can still cause tubal damage. |
Risk Factors
| Risk Factor | Notes |
|---|---|
| Young Age | less than 25 years. Cervical ectopy. |
| Multiple Sexual Partners | Increased STI exposure. |
| New Sexual Partner | Within past 3 months. |
| Previous STI / PID | Recurrence common. |
| IUD Insertion | Small risk in first 3 weeks post-insertion. |
| Uterine Instrumentation | Termination of pregnancy, Hysteroscopy, D&C. |
| No Barrier Contraception | Condoms protective. |
3. Aetiology
Causative Organisms
| Organism | Notes |
|---|---|
| Chlamydia trachomatis | Most common identified cause (~25-40% of diagnosed PID). Often subclinical. |
| Neisseria gonorrhoeae | More likely to cause symptomatic/acute PID. Increasing resistance. |
| Mycoplasma genitalium | Increasingly recognised. May not respond to standard treatment. |
| Anaerobes | Bacteroides, Peptostreptococcus. Part of polymicrobial infection. |
| Enteric Bacteria | E. coli, Streptococci. |
| Mixed / Polymicrobial | Common. ~30-40% of PID is polymicrobial. |
Mechanism
- Cervical Infection: Chlamydia/Gonorrhoea infects cervix.
- Ascending Infection: Bacteria ascend through endometrium to fallopian tubes and peritoneum.
- Inflammation: Salpingitis (Tubal inflammation), Oophoritis, Pelvic peritonitis.
- Tubal Damage: Scarring → Tubal occlusion → Infertility, Ectopic pregnancy.
4. Clinical Presentation
Symptoms
| Symptom | Notes |
|---|---|
| Lower Abdominal / Pelvic Pain | Usually bilateral. Recent onset. May be mild or severe. |
| Deep Dyspareunia | Pain during/after intercourse. |
| Abnormal Vaginal Discharge | May be purulent. |
| Intermenstrual Bleeding | Abnormal bleeding. |
| Postcoital Bleeding | |
| Dysuria | (Urethritis may coexist). |
| Fever | Variable. May be absent in mild PID. |
| Right Upper Quadrant Pain | Consider Fitz-Hugh-Curtis Syndrome (Perihepatitis). |
Examination Findings
| Finding | Notes |
|---|---|
| Lower Abdominal Tenderness | Bilateral. May have rebound/guarding if peritonitis. |
| Cervical Motion Tenderness ("Chandelier Sign") | Pain on moving cervix during bimanual exam. Classic sign. |
| Adnexal Tenderness | Tender fallopian tubes/Ovaries. |
| Uterine Tenderness | |
| Purulent Cervical Discharge | May be visible on speculum exam. |
| Fever | >38°C. |
| Adnexal Mass | Consider Tubo-Ovarian Abscess (TOA). |
Clinical Spectrum
| Severity | Features |
|---|---|
| Mild | Lower abdominal pain, Cervical motion tenderness, No fever. |
| Moderate | Significant pain, Fever, Raised inflammatory markers. |
| Severe | TOA, Peritonitis, Sepsis. May require hospital admission. |
5. Differential Diagnosis
| Condition | Key Features |
|---|---|
| PID | Bilateral lower abdominal pain, Cervical motion tenderness, Discharge, STI risk. |
| Ectopic Pregnancy | MUST EXCLUDE. Positive pregnancy test, Unilateral pain, Vaginal bleeding. |
| Appendicitis | Right iliac fossa pain, Migratory from periumbilical, Nausea/Vomiting. |
| Ovarian Cyst Torsion/Rupture | Sudden severe unilateral pain, Nausea. |
| Endometriosis | Cyclical pain, Dysmenorrhoea, Dyspareunia. Chronic. |
| Urinary Tract Infection | Dysuria, Frequency, Suprapubic pain, Haematuria. |
| Irritable Bowel Syndrome | Chronic, Bloating, Altered bowel habit. |
6. Investigations
Essential Investigations
| Investigation | Notes |
|---|---|
| Pregnancy Test | MANDATORY. Ectopic must be excluded. |
| Endocervical/Vaginal Swabs | NAAT for Chlamydia and Gonorrhoea. Culture for Gonorrhoea (Sensitivities – Rising resistance). Consider Mycoplasma genitalium if available. |
| High Vaginal Swab (HVS) | Bacterial vaginosis, Candida, Trichomonas (Less relevant for PID but may coexist). |
| Microscopy (If Available) | >30 WBC/HPF on endocervical gram stain supports diagnosis. |
| HIV / Syphilis Serology | Offer full STI screen. |
Additional Investigations
| Investigation | Indication |
|---|---|
| FBC, CRP | Raised WCC and CRP support diagnosis but may be normal in mild PID. |
| Pelvic USS/TVUS | If TOA suspected, Pelvic mass, Diagnostic uncertainty. Thickened, Fluid-filled tubes. Free fluid. TOA = Complex adnexal mass. |
| Laparoscopy | Gold standard for diagnosis (Direct visualization). Rarely needed. Reserved for diagnostic uncertainty or suspected abscess needing drainage. |
7. Management
Management Algorithm
SUSPECTED PID
(Pelvic pain, Cervical motion tenderness, Discharge, STI risk)
↓
EXCLUDE ECTOPIC PREGNANCY
(Pregnancy test mandatory)
↓
ASSESS SEVERITY
- Mild: Outpatient treatment
- Moderate/Severe: Hospital admission
- TOA / Peritonitis / Sepsis: Emergency
↓
MILD PID (Outpatient)
┌──────────────────────────────────────────────────────────┐
│ EMPIRICAL ANTIBIOTICS (BASHH Guidelines) │
│ │
│ **IM Ceftriaxone 1g SINGLE DOSE** │
│ + │
│ **Doxycycline 100mg BD PO for 14 days** │
│ + │
│ **Metronidazole 400mg BD PO for 14 days** │
│ │
│ OR (Alternative if Ceftriaxone not available): │
│ - Ofloxacin 400mg BD PO + Metronidazole 400mg BD PO │
│ for 14 days (Avoid in high Gonorrhoea risk/prevalence)│
└──────────────────────────────────────────────────────────┘
↓
MODERATE/SEVERE PID (Admission)
┌──────────────────────────────────────────────────────────┐
│ IV ANTIBIOTICS │
│ - **Ceftriaxone 2g OD IV** │
│ + **Doxycycline 100mg BD PO/IV** │
│ + **Metronidazole 500mg TDS IV** │
│ │
│ Switch to oral after clinical improvement (Usually 24-48h)│
│ Complete 14 days total │
└──────────────────────────────────────────────────────────┘
↓
TUBO-OVARIAN ABSCESS (TOA)
┌──────────────────────────────────────────────────────────┐
│ - IV Antibiotics as above │
│ - Surgical drainage if: │
│ - Large abscess (>8cm) │
│ - No response to antibiotics (48-72h) │
│ - Suspected rupture │
│ - US-guided aspiration or Laparoscopic/Open drainage │
└──────────────────────────────────────────────────────────┘
↓
PARTNER NOTIFICATION & TREATMENT
- Trace contacts from past 6 months
- Treat partners for Chlamydia and Gonorrhoea
- Avoid intercourse until partner treated
Antibiotic Rationale
| Drug | Covers |
|---|---|
| Ceftriaxone | Gonorrhoea (Including resistant strains). |
| Doxycycline | Chlamydia, Mycoplasma. |
| Metronidazole | Anaerobes, BV. |
General Measures
| Measure | Notes |
|---|---|
| Analgesia | NSAIDs, Paracetamol. |
| Avoid Sexual Intercourse | Until patient and partner(s) have completed treatment. |
| IUD | Usually does NOT need to be removed. May remove if no response to treatment. |
| Remove IUD | If TOA or severe/unresponsive PID. |
| Follow-Up | Review at 72 hours and 2-4 weeks. |
8. Complications
| Complication | Notes |
|---|---|
| Tubo-Ovarian Abscess (TOA) | Collection of pus involving tube and ovary. May require drainage. Can rupture → Peritonitis. |
| Fitz-Hugh-Curtis Syndrome | Perihepatitis. "Violin string" adhesions between liver and anterior abdominal wall. Right upper quadrant pain. |
| Infertility | ~10% after one episode, ~25% after two, ~50% after three. Due to tubal scarring/occlusion. |
| Ectopic Pregnancy | 6-10 fold increased risk. Due to tubal damage. |
| Chronic Pelvic Pain | ~20% of women. Adhesions. |
| Recurrent PID | Without partner treatment. |
9. Prognosis and Outcomes
| Factor | Notes |
|---|---|
| With Prompt Treatment | Symptoms improve in 72 hours. Antibiotics complete course. |
| Delayed Treatment | Increased risk of complications (Infertility, Chronic pain). |
| Subclinical PID | May cause silent tubal damage. |
| Recurrence | Common if partners not treated. |
10. Evidence and Guidelines
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| PID Management | BASHH (2019) | Low threshold to treat. Ceftriaxone + Doxycycline + Metronidazole. Partner notification. |
| STI Testing | NICE | Full STI screen. Contact tracing. |
Key Points
- Do NOT wait for results to treat PID. Treat empirically.
- Partner management is essential to prevent reinfection.
- Mycoplasma genitalium may not respond to standard treatment. Consider if treatment failure.
11. Patient and Layperson Explanation
What is PID?
Pelvic Inflammatory Disease (PID) is an infection of the womb (Uterus), Fallopian tubes, and surrounding tissue. It is usually caused by sexually transmitted infections (STIs) like Chlamydia or Gonorrhoea that spread upwards from the vagina.
What are the symptoms?
- Pain in the lower tummy (Pelvis).
- Pain during sex.
- Unusual vaginal discharge.
- Bleeding between periods or after sex.
- Sometimes fever.
Some women have no symptoms but can still have damage happening inside.
Is it serious?
Yes, It can be. If not treated quickly, PID can cause:
- Infertility (Difficulty getting pregnant) – Due to scarring of the tubes.
- Ectopic pregnancy – A pregnancy in the wrong place (Fallopian tube).
- Long-term pelvic pain.
What is the treatment?
- Antibiotics – Usually a combination for at least 14 days.
- Rest and painkillers.
- Your partner(s) must be treated too – Otherwise you can get infected again.
- Avoid sex until both you and your partner have finished treatment.
Will I be able to have children?
Most women treated promptly for PID go on to have normal pregnancies. The key is getting treatment early. Repeated infections increase the risk of fertility problems.
12. References
Primary Sources
- British Association for Sexual Health and HIV (BASHH). UK National Guideline for the Management of Pelvic Inflammatory Disease. 2019.
- Workowski KA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187. PMID: 34292926.
- Ross JDC. Pelvic inflammatory disease. BMJ Clin Evid. 2013;2013:1606. PMID: 24330617.
13. Examination Focus
Common Exam Questions
- Most Common Cause: "What is the most common causative organism of PID?"
- Answer: Chlamydia trachomatis.
- Examination Finding: "What is the Chandelier Sign?"
- Answer: Cervical Motion Tenderness – Pain on moving the cervix during bimanual examination.
- Complication with RUQ Pain: "What is Fitz-Hugh-Curtis Syndrome?"
- Answer: Perihepatitis – Inflammation of the liver capsule with adhesions ("Violin string"). Causes right upper quadrant pain.
- Antibiotic Regimen (Outpatient): "What is the first-line outpatient treatment for PID?"
- Answer: Ceftriaxone 1g IM stat + Doxycycline 100mg BD PO 14 days + Metronidazole 400mg BD PO 14 days.
Viva Points
- Always Exclude Ectopic: Pregnancy test mandatory.
- Low Threshold to Treat: Don't wait for swab results. Consequences of untreated PID are severe.
- IUD: Usually NOT removed unless severe/unresponsive PID or TOA.
- Partner Notification: Essential. Without it, reinfection is common.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.