Pelvic Inflammatory Disease

❍ At a glance

• Diagnose and treat empirically when a sexually active woman has lower abdominal pain plus cervical motion tenderness, uterine tenderness, or adnexal tenderness on bimanual examination. The threshold is intentionally low - the cost of undertreating PID (tubal damage, subfertility, ectopic pregnancy risk) far outweighs the cost of treating a patient who turns out not to have it.
• Investigation should not delay treatment. Start empirical antibiotics based on clinical diagnosis, then adjust when swab results return. Pregnancy test is mandatory before treatment.
• NZ gonorrhoea resistance patterns matter: oral cefixime is no longer considered adequate for gonorrhoea treatment in NZ. Check current NZSHS guidelines at time of prescribing - outpatient PID regimens typically include IM/IV ceftriaxone plus doxycycline plus metronidazole. Recommendations are updated regularly.³
• Review at 72 hours: if no clinical improvement, reassess and admit. Partner notification is mandatory for all partners within the past 6 months.

❍ Presentation, investigation and management

Clinical diagnosis: sexually active woman with pelvic or lower abdominal pain and one or more of: cervical motion tenderness, uterine tenderness, or adnexal tenderness on bimanual examination. Additional features increasing probability include mucopurulent vaginal discharge, fever (present in a minority - absence does not exclude PID), raised WBC/CRP/ESR, and positive NAAT. The mildest form may present with only cervical motion tenderness and minimal systemic features - this is the most commonly missed presentation.

Investigation: endocervical or self-collected vaginal swab for NAAT (chlamydia and gonorrhoea); send culture and sensitivity if gonorrhoea is suspected. Urine pregnancy test (essential - to exclude ectopic pregnancy and because some antibiotics are contraindicated in pregnancy). FBC and CRP. Pelvic ultrasound to detect tubo-ovarian abscess (TOA) and exclude other diagnoses. A normal ultrasound does not exclude PID. Consider hepatitis B, C, and HIV as part of a broader STI screen.

Treatment: empirical antibiotics before swab results. NZ outpatient regimen (mild to moderate PID): check current NZSHS guidelines at time of prescribing - typically includes a single dose of IM/IV ceftriaxone plus doxycycline 100 mg twice daily plus metronidazole 400 mg twice daily for 14 days.³ Ensure adequate analgesia. Review in 72 hours. Partner notification is mandatory: all partners in the past 6 months must be tested and treated, even if asymptomatic. An IUD does not need routine removal if PID is diagnosed - leave in situ unless no improvement at 72 hours.

❍ Complications and referral criteria

Tubo-ovarian abscess requires admission, IV antibiotics, and possible surgical drainage. Suspect if systemic features, palpable adnexal mass, or failure to improve on outpatient antibiotics. Admit for IV antibiotics and gynaecology review for any of: suspected TOA, systemic illness (fever over 38.5 C, peritonism), failure to improve at 72 hours, pregnancy, inability to tolerate oral antibiotics, or immunosuppression.

Long-term sequelae: chronic pelvic pain affects approximately 20% of women after one episode; tubal factor subfertility occurs in approximately 10-15% after one episode and 30-40% after three or more episodes;² ectopic pregnancy risk is increased 6-10-fold. Counselling women about these sequelae after treatment is part of good clinical care and reinforces the rationale for prompt, complete antibiotic courses. Refer to sexual health service for partner notification support, complex STI management, or recurrent PID.