Pelvic Inflammatory Disease
Diagnosis
PID lacks a diagnostic gold standard, so clinical diagnosis is pragmatic: the positive predictive value of clinical assessment is only 65–90% against laparoscopy. Empirical antibiotic treatment should be started with a low threshold in any sexually active woman with recent-onset lower abdominal pain and local tenderness on bimanual examination, once pregnancy is excluded and no other cause identified — delaying treatment increases the risk of long-term sequelae (ectopic pregnancy, infertility, chronic pelvic pain). Risk is highest under age 25, with a new partner, and without barrier contraception.
Recommended tests: NAAT for gonorrhoea, chlamydia and Mycoplasma genitalium from the lower genital tract — a positive result supports the diagnosis and guides therapy, but a negative result does not exclude PID. Raised ESR/CRP/WCC support the diagnosis but are non-specific and usually only abnormal in moderate–severe disease. Absence of pus cells on a Gram-stained vaginal smear has a good negative predictive value (95%). Ultrasound has limited value in uncomplicated PID but is useful if abscess or hydrosalpinx is suspected; MRI/CT can help exclude differentials (ectopic pregnancy, appendicitis, ovarian cyst accident) but are not routine.
Causative Organisms
Infection ascends from the endocervix, causing endometritis, salpingitis, parametritis, oophoritis, tubo-ovarian abscess and/or pelvic peritonitis. Chlamydia trachomatis is the commonest identified cause (14–35% of cases). Neisseria gonorrhoeae is also implicated but accounts for under 3% of UK PID. Mycoplasma genitalium is increasingly recognised as a likely cause of upper genital tract infection. Gardnerella vaginalis, anaerobes (Prevotella, Atopobium, Leptotrichia) and other vaginal flora may also contribute. A substantial proportion of cases are pathogen-negative.
Antibiotic Treatment
Outpatient (mild–moderate disease), all courses 14 days:
- IM ceftriaxone 1g single dose + oral doxycycline 100mg twice daily + oral metronidazole 400mg twice daily (first-line)
- Oral ofloxacin 400mg twice daily + oral metronidazole 400mg twice daily (avoid if high risk of gonococcal PID — quinolone resistance)
- Oral moxifloxacin 400mg once daily (best M. genitalium activity; recommended first-line specifically for confirmed/suspected M. genitalium PID, otherwise second-line following EMA fluoroquinolone safety advice)
Inpatient (indicated for surgical emergency not excluded, failed oral therapy, severe disease, tubo-ovarian abscess, intolerance of oral therapy, or pregnancy):
- IV ceftriaxone 2g daily + IV/oral doxycycline 100mg twice daily, stepping down to oral doxycycline + metronidazole 400mg twice daily to complete 14 days
- IV clindamycin 900mg three times daily + IV gentamicin, stepping down to oral clindamycin or doxycycline + metronidazole to complete 14 days
Male partners should receive empirical doxycycline (rather than azithromycin) to limit macrolide-resistance selection in M. genitalium. An IUD may be left in situ in mild–moderate PID with review at 48–72 hours; remove if no improvement.
High-Yield Exam Points
- RCOG GTG 32 is archived — BASHH is now the authoritative UK source for PID management.
- C. trachomatis is the most commonly identified single organism; gonococcal PID is uncommon in the UK (<3%); M. genitalium is an important and often-undertested cause.
- Diagnosis is clinical; a low threshold for empirical treatment is recommended because delay worsens fertility outcomes.
- First-line outpatient regimen: IM ceftriaxone 1g + oral doxycycline 100mg BD + metronidazole 400mg BD for 14 days.
- Fluoroquinolones (ofloxacin/moxifloxacin) are now second-line except moxifloxacin remains first-line for M. genitalium-associated PID.
- Tubo-ovarian abscess, pregnancy, or failed oral therapy are indications for admission and IV therapy.
Source: RCOG Green-top Guideline No. 32 (Archived — RCOG's guidance page now directs readers to the BASHH UK National Guideline for the Management of Pelvic Inflammatory Disease as the current source) (BASHH guideline last full revision 2018 (lead author Jonathan Ross), with a 2019 interim update; the archived RCOG GTG 32 itself dated from 2008 (2nd edition))
Read the original on rcog.org.uk
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