Pelvic Inflammatory Disease

Pelvic inflammatory disease (PID) is an ascending polymicrobial infection of the upper female genital tract — endometrium, fallopian tubes, ovaries and adjacent pelvic peritoneum. It is a high-yield gynaecology topic because of its classic causative organisms, the "chandelier sign," Fitz-Hugh-Curtis syndrome and the standard CDC antibiotic regimens, all of which are reliable NEET PG recall items.

Definition & spectrum

PID is a clinical syndrome resulting from spontaneous ascension of microorganisms from the cervix and vagina to the upper reproductive tract, producing any combination of endometritis, salpingitis, oophoritis, tubo-ovarian abscess (TOA) and pelvic peritonitis. It is overwhelmingly a sexually transmitted, ascending infection, and is therefore largely a disease of sexually active reproductive-age women.

The disease exists along a continuum:

Site involved	Term	Comment
Endometrium	Endometritis	Earliest stage, abnormal bleeding
Fallopian tube	Salpingitis	Hallmark lesion of PID; tubal damage
Tube + ovary (abscess)	Tubo-ovarian abscess	Walled-off collection, palpable mass
Pelvic peritoneum	Pelvic peritonitis	Guarding, rebound
Liver capsule	Fitz-Hugh-Curtis (perihepatitis)	RUQ pain, "violin-string" adhesions

High-yield: PID is an ascending infection. It is NOT haematogenous (except genital tuberculosis, which IS haematogenous/descending and is the classic exception).

Etiology — causative organisms

PID is polymicrobial. The two most important sexually transmitted pathogens are:

1. Neisseria gonorrhoeae — Gram-negative diplococcus
2. Chlamydia trachomatis (serovars D–K) — obligate intracellular organism; the single most common cause in many populations and the commonest cause of "silent" PID.

Other organisms include endogenous anaerobes and facultative flora that join after the initial STI breaches cervical defences:

• Anaerobes: Bacteroides, Peptostreptococcus, Prevotella
• Facultative: Gardnerella vaginalis, E. coli, Streptococcus, Haemophilus influenzae
• Mycoplasma genitalium (increasingly recognised)
• Actinomyces israelii — classically associated with IUCD use
• Mycobacterium tuberculosis — genital TB; haematogenous, causes infertility, beaded tubes

Organism	Key clue / NEET point
C. trachomatis	Most common; silent/subclinical; intracellular
N. gonorrhoeae	More acute, florid presentation; intracellular diplococci
Anaerobes	Dominate TOA; foul-smelling pus
Actinomyces	IUCD; sulphur granules
M. tuberculosis	Genital TB, haematogenous, infertility, beaded tubes

High-yield: Chlamydia causes the most damage with the fewest symptoms ("silent PID"), so it is the leading infectious cause of tubal-factor infertility.

Risk factors

• Age <25 years, early coitarche
• Multiple sexual partners, new partner, unprotected intercourse
• Prior PID or STI
• Instrumentation: D&C, hysteroscopy, HSG, IUCD insertion (highest risk in first 3 weeks)
• Bacterial vaginosis
• Douching

Protective: combined oral contraceptive pills (thickened cervical mucus), barrier contraception, pregnancy (decidua + mucus plug).

High-yield: With IUCDs, the risk of PID is concentrated in the first 3 weeks after insertion — beyond that the risk approaches baseline.

Pathophysiology

Cervical defences (mucus plug, columnar epithelium) are normally a barrier. Menstruation, instrumentation and STIs disrupt the barrier, allowing organisms to ascend. Sequence:

Cervicitis → endometritis → salpingitis → tubal mucosal damage / pyosalpinx → tubo-ovarian abscess → pelvic peritonitis → (perihepatitis = Fitz-Hugh-Curtis)

Salpingitis causes loss of ciliated epithelium, intraluminal adhesions and tubal scarring. Healing seals the fimbrial end → hydrosalpinx. The destroyed, scarred tube is responsible for the three classic long-term sequelae: infertility, ectopic pregnancy and chronic pelvic pain.

High-yield: Retrograde menstruation and ascent are favoured during menses — PID often presents just after a menstrual period, especially gonococcal PID.

Clinical features

PID is notoriously variable. Many cases are subclinical. Classic acute presentation:

• Lower abdominal / bilateral pelvic pain (most consistent symptom)
• Abnormal vaginal discharge (mucopurulent)
• Abnormal uterine bleeding (intermenstrual / postcoital)
• Deep dyspareunia
• Fever, malaise (more with gonococcal)
• Dysuria

Signs on examination:

• Lower abdominal tenderness ± guarding/rebound
• Cervical motion tenderness (CMT) — the "Chandelier sign" (pain so severe on moving the cervix that the patient "reaches for the chandelier")
• Adnexal tenderness, adnexal mass (if TOA)
• Mucopurulent cervical discharge / friable cervix

High-yield: The classic triad of examination findings (the "minimum criteria") = cervical motion tenderness + uterine tenderness + adnexal tenderness. Any one in an at-risk woman with pelvic pain warrants empirical treatment.

Fitz-Hugh-Curtis syndrome (perihepatitis)

Inflammation of the liver capsule and adjacent peritoneum producing right upper quadrant (RUQ) pain that may mimic cholecystitis. Laparoscopy shows characteristic "violin-string" (or piano-wire) adhesions between the liver capsule and the anterior abdominal wall/diaphragm. Both Chlamydia and gonococcus can cause it; Chlamydia is the more common association.

High-yield: RUQ pain + pelvic infection + violin-string adhesions = Fitz-Hugh-Curtis syndrome. A perennial single-best-answer favourite.

Diagnosis

PID is primarily a clinical diagnosis — treatment should not be delayed for confirmation, because the cost of missed PID (infertility) is high.

CDC diagnostic criteria

Minimum criteria (begin empirical treatment in a sexually active young woman with pelvic/lower-abdominal pain and no other cause, if ≥1 present):

1. Cervical motion tenderness, OR
2. Uterine tenderness, OR
3. Adnexal tenderness.

Additional (supportive) criteria — increase specificity:

• Oral temperature >38.3°C (101°F)
• Abnormal mucopurulent cervical/vaginal discharge
• Abundant WBCs on saline wet mount of vaginal secretions
• Raised ESR / CRP
• Documented cervical infection with N. gonorrhoeae or C. trachomatis

Definitive (most specific) criteria:

• Endometrial biopsy showing endometritis
• Transvaginal USG / MRI showing thickened, fluid-filled tubes ± free pelvic fluid ± TOA, or Doppler suggesting tubal hyperaemia
• Laparoscopy showing abnormalities consistent with PID

High-yield: Laparoscopy is the gold standard for diagnosing PID. It allows direct visualisation, grading of severity and culture from the tube — but is invasive, so it is NOT done routinely; it is reserved for diagnostic uncertainty or failed therapy.

Investigations

• NAAT (nucleic acid amplification test) for N. gonorrhoeae and C. trachomatis — investigation of choice for the organism
• Endocervical Gram stain (intracellular Gram-negative diplococci = gonococcus)
• Urine pregnancy test (mandatory — rule out ectopic pregnancy)
• CBC, ESR, CRP
• Transvaginal ultrasonography — first-line imaging; detects TOA, hydrosalpinx, "cogwheel sign"
• HIV, syphilis and other STI screen
• Test the partner

Management

Principles

• Treat empirically and early; never wait for cultures.
• Regimens must cover gonococcus, chlamydia AND anaerobes.
• Treat sexual partners; advise abstinence till both complete therapy.
• Remove IUCD only if no clinical improvement after 48–72 hours.

Outpatient (mild–moderate PID) — CDC regimen

Ceftriaxone 500 mg IM single dose + Doxycycline 100 mg PO BD × 14 days + Metronidazole 500 mg PO BD × 14 days.

(Ceftriaxone → gonococcus; doxycycline → chlamydia; metronidazole → anaerobes.)

Indications for hospital admission / IV therapy

• Pregnancy
• Tubo-ovarian abscess
• Severe illness, high fever, vomiting (cannot tolerate oral)
• Failed outpatient therapy (no response in 72 h)
• Surgical emergency cannot be excluded (e.g. appendicitis)
• Adolescents / poor compliance

Inpatient (parenteral) regimen

Cefotetan or Cefoxitin IV + Doxycycline, OR Clindamycin + Gentamicin IV; switch to oral doxycycline ± metronidazole to complete 14 days.

Setting	Regimen	Targets
Outpatient	Ceftriaxone IM + Doxycycline PO + Metronidazole PO	GC + Chlamydia + anaerobes
Inpatient	Cefoxitin/Cefotetan IV + Doxycycline	GC + Chlamydia + anaerobes
Alternative inpatient	Clindamycin + Gentamicin IV	Anaerobes + Gram-negatives
TOA not responding	Add metronidazole; image-guided drainage / surgery	Anaerobic abscess

High-yield: The single-drug-of-choice question is often answered as the combination: a cephalosporin (gonococcus) + doxycycline (chlamydia) + metronidazole (anaerobes). For an isolated chlamydial cervicitis the answer is azithromycin/doxycycline; for gonococcal cervicitis, ceftriaxone.

Surgical management

• Image-guided drainage of TOA that fails antibiotics (>48–72 h)
• Laparoscopy/laparotomy for ruptured TOA (surgical emergency with sepsis)
• Salpingectomy for ruptured/non-responding abscess

High-yield: A ruptured tubo-ovarian abscess is a life-threatening surgical emergency → immediate laparotomy.

Complications & sequelae

Short-term: tubo-ovarian abscess, ruptured TOA with peritonitis/septic shock, Fitz-Hugh-Curtis perihepatitis.

Long-term (the examiner's favourites):

1. Infertility — tubal-factor; risk rises with each episode (≈ 8% after 1, ≈ 20% after 2, ≈ 40–50% after 3 episodes).
2. Ectopic pregnancy — 6- to 10-fold increased risk due to tubal scarring.
3. Chronic pelvic pain — adhesions, hydrosalpinx.
4. Hydrosalpinx, recurrent PID.

High-yield: Each episode of PID roughly doubles the risk of infertility — a classic numbers question.

Key differential diagnoses

Condition	Distinguishing clue
Ectopic pregnancy	Positive UPT, unilateral pain, amenorrhoea, β-hCG
Acute appendicitis	RIF pain, McBurney point, anorexia, raised neutrophils
Ovarian torsion	Sudden severe unilateral pain, vomiting, whirlpool sign on Doppler
Ruptured/haemorrhagic ovarian cyst	Mid-cycle sudden pain, free fluid, UPT negative
Endometriosis	Cyclical pain, dysmenorrhoea, infertility, normal WBC
UTI / pyelonephritis	Dysuria, loin pain, pyuria, positive urine culture
Diverticulitis	Older, LIF pain, altered bowel habit

Approach to a young woman with acute pelvic pain:

1. Pregnancy test first → rule out ectopic.
2. Examine for CMT, adnexal mass and signs of peritonism.
3. TVS to look for TOA / free fluid / adnexal pathology.
4. Apply CDC minimum criteria → if met, treat empirically.
5. Reassess at 72 h → no improvement = re-image, consider laparoscopy or surgery, remove IUCD.

Recently asked / exam angle

• Chandelier sign = severe cervical motion tenderness — direct recall.
• Fitz-Hugh-Curtis syndrome = perihepatitis with violin-string adhesions; can present as RUQ pain mimicking cholecystitis.
• Laparoscopy = gold standard for diagnosis of PID.
• Commonest organism = Chlamydia trachomatis; most acute = N. gonorrhoeae; both are intracellular.
• The outpatient CDC regimen (ceftriaxone + doxycycline + metronidazole) and what each drug targets.
• Actinomyces ↔ IUCD; sulphur granules.
• OCPs are protective; IUCD risk is highest in the first 3 weeks.
• Genital TB is the haematogenous/descending exception to "ascending infection."
• Long-term sequelae triad: infertility, ectopic pregnancy, chronic pelvic pain.
• Mandatory step in any pelvic-pain question = rule out pregnancy / ectopic.

Mnemonics:

• Causes/targets "CAN" — Chlamydia, Anaerobes, Neisseria — and treatment covers all three (doxycycline, metronidazole, ceftriaxone).
• Sequelae "PID-3" — Pain (chronic pelvic), Infertility, Displaced pregnancy (ectopic).

Rapid revision

1. PID = ascending polymicrobial infection of the upper genital tract (endometrium → tubes → ovaries → peritoneum).
2. Commonest organism = Chlamydia trachomatis (silent); most florid = N. gonorrhoeae; both intracellular.
3. Genital TB is the haematogenous, descending exception.
4. CDC minimum criteria = cervical motion / uterine / adnexal tenderness in an at-risk woman → treat empirically.
5. Chandelier sign = severe cervical motion tenderness.
6. Fitz-Hugh-Curtis = perihepatitis with violin-string adhesions, RUQ pain.
7. Laparoscopy = gold-standard diagnosis; TVS = first-line imaging; NAAT identifies the organism.
8. Always do a pregnancy test to exclude ectopic before settling on PID.
9. Outpatient Rx: ceftriaxone IM + doxycycline 14 d + metronidazole 14 d.
10. Admit for pregnancy, TOA, severe illness, failed oral therapy, or surgical doubt.
11. Remove IUCD only if no response at 48–72 h; ruptured TOA = surgical emergency.
12. Sequelae: infertility, ectopic pregnancy, chronic pelvic pain — risk multiplies with each episode; OCPs are protective.