Pelvic Inflammatory Disease (PID)

🔍 When to Suspect

A sexually active person with recent onset lower abdominal/pelvic pain, deep dyspareunia, and/or abnormal vaginal discharge

From the full topic in The Ocean Library: Pelvic Inflammatory Disease (PID)

🧭 When to suspect

Pelvic inflammatory disease (PID) is infection ascending from the endocervix to the upper genital tract, producing endometritis, salpingitis, parametritis, oophoritis, tubo-ovarian abscess and/or pelvic peritonitis. It is most common in sexually active women under 25. Chlamydia trachomatis is the commonest identified cause, Mycoplasma genitalium is increasingly recognised, and Neisseria gonorrhoeae accounts for under 3% of UK cases – but a large proportion of PID is pathogen-negative, so the diagnosis is clinical, not microbiological.

Suspect PID in any sexually active woman with recent-onset lower abdominal or pelvic pain (usually bilateral) and pelvic tenderness on bimanual examination, once pregnancy has been excluded and no other cause is evident. Supporting features include deep dyspareunia, abnormal vaginal discharge, abnormal bleeding (intermenstrual or post-coital), secondary dysmenorrhoea, and fever in moderate-to-severe disease.

Because clinical signs lack sensitivity and there is no definitive diagnostic test, adopt a low threshold for empirical treatment – delay increases the risk of infertility, ectopic pregnancy and chronic pelvic pain. Key risk factors are age under 25, a new or multiple sexual partners, absent barrier contraception, previous sexually transmitted infection (STI) or PID, and recent instrumentation of the cervix – particularly intrauterine device (IUD) or intrauterine system (IUS) insertion within the last 4–6 weeks, termination, or hysteroscopy.

Differential to exclude	Pointer
Ectopic pregnancy	Always exclude with a pregnancy test – mimics PID and is immediately life-threatening.
Acute appendicitis	Anorexia, nausea and vomiting more prominent; pain often migrates to the right iliac fossa.
Ovarian cyst accident (torsion or rupture)	Sudden-onset, frequently unilateral pain; suspect with an adnexal mass.
Endometriosis	Cyclical, longstanding symptoms linked to menstruation.
Urinary tract infection	Dysuria and frequency predominate; confirm on urinalysis and culture.
Irritable bowel syndrome (IBS) / functional pain	Altered bowel habit; chronic, fluctuating course.

Source: BASHH · RCOG

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