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 one or more of:

• Endometritis

• Salpingitis

• Parametritis

• Oophoritis

• Tubo-ovarian abscess

• Pelvic peritonitis

It is most common in sexually active women under 25. Causes:

• Chlamydia trachomatis is the commonest identified cause.

• Mycoplasma genitalium is increasingly recognised.

• Neisseria gonorrhoeae accounts for under 3% of UK cases.

A large proportion of PID is pathogen-negative, so the diagnosis is clinical, not microbiological.

Suspect PID in any sexually active woman, once pregnancy has been excluded and no other cause is evident, with:

• Recent-onset lower abdominal or pelvic pain (usually bilateral), and

• Pelvic tenderness on bimanual examination

Supporting features include:

• Deep dyspareunia

• Abnormal vaginal discharge

• Abnormal bleeding (intermenstrual or post-coital)

• Secondary dysmenorrhoea

• 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

• New or multiple sexual partners

• Absent barrier contraception

• Previous sexually transmitted infection (STI) or PID

• 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) or functional pain	• Altered bowel habit • Chronic, fluctuating course

Source: BASHH · RCOG

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