Annotations only — chart still shows the full chemistry of each drug.
1. Clinical Syndrome
Ascending infection of the upper genital tract (endometritis, salpingitis, tubo-ovarian abscess, pelvic peritonitis) in women, typically from sexually transmitted pathogens. Clinical diagnosis — minimum criteria: lower abdominal/pelvic pain + cervical motion / uterine / adnexal tenderness in a sexually active woman. Treat empirically because delays lead to tubal factor infertility, ectopic pregnancy, chronic pelvic pain.
Excludes: tubo-ovarian abscess (TOA — usually needs IV therapy ± drainage; see escalation), pregnancy (rule out — always βhCG), appendicitis, ovarian torsion, ectopic pregnancy, endometriosis, ruptured ovarian cyst.
2. Pathogens
Consider the patient: Sexually active reproductive-age woman, IUD insertion <3 wk (transient risk), recent gynecologic procedure.
Consider the case: Polymicrobial — empiric must cover GC + CT + anaerobes ± enteric gram-negatives + streptococci. NAAT for GC/CT at presentation. Pregnancy test mandatory. Pelvic exam + speculum. Ultrasound or CT if TOA suspected (severe pain, fever, mass, no improvement after 48 h). Sepsis criteria → admit + IV.
Common
- Neisseria gonorrhoeae
Primary trigger in younger / sexually active women.
- Chlamydia trachomatis
Often clinically silent until PID; most common cause of tubal infertility.
- Neisseria gonorrhoeae
Less common
- Bacteroides fragilis
Anaerobic ascent; metronidazole coverage essential, especially TOA or after IUD.
- Escherichia coli
Enteric gram-negative ascent.
- Streptococcus pyogenes (Group A Strep)
Group A strep PID rare but severe.
- Bacteroides fragilis
3. Empiric Therapy
| Tier | First choice | Alternatives | Duration | Comments |
|---|---|---|---|---|
| Outpatient |
|
| 14 days for oral regimens | Outpatient if hemodynamically stable, tolerating PO, no surgical abdomen, no TOA, not pregnant, reliable follow-up at 72 h. **Reassess at 72 h** — clinical improvement (less pain, fever down) expected; failure → admit + IV. **Treat partners** (within 60 d) + STI/HIV testing. |
| Admitted to ward |
|
| Until clinical improvement ≥24 h, then transition to PO doxy + metronidazole to complete 14 d total | **Admit if:** TOA, pregnancy, severe illness / sepsis, surgical abdomen unable to exclude, immunocompromised, failed outpatient at 72 h, can't tolerate / be reliable with PO. **TOA** ≥7–9 cm or rupture → consult IR/gyn for drainage. |
4. Directed Therapy
TOA (tubo-ovarian abscess): Admit, IV antibiotics 24–48 h, ultrasound or CT to confirm + size. <7 cm + improving → continue IV → PO 14 d. ≥7 cm or no improvement at 48–72 h → IR drainage or surgical drainage. Rupture → emergent laparoscopy.
Mycoplasma genitalium screening if PID treatment failure: NAAT + susceptibility-guided treatment (moxifloxacin × 14 d for macrolide-resistant).
Actinomyces with chronic IUD: extended PCN or doxy course (3 mo+) plus IUD removal — uncommon, atypical.
Fitz-Hugh-Curtis syndrome (perihepatitis — RUQ pain, peri-hepatic adhesions): treat as PID — same regimen, same duration; no specific addition needed.
5. Monitoring
72-hour reassessment is the linchpin for outpatient. Improvement → continue oral. No improvement / worsening → admit + IV + imaging. Test-of-cure NAAT at 3 months for reinfection (high recurrence). Fertility counseling — single episode = ~12% infertility, two = 25%, three = 50%; counsel partners + contraception. STI panel (HIV, syphilis, hepatitis screen).
Toxicity: doxycycline esophagitis / photosensitivity; metronidazole disulfiram-like reaction with alcohol (counsel), peripheral neuropathy with prolonged use; ceftriaxone biliary sludge.
Pearls
Treat on minimum criteria (pelvic pain + CMT/UT/AT in sexually active woman) — sensitivity > specificity to prevent infertility. 14-day outpatient regimen now includes metronidazole routinely (anaerobic coverage). Admit pregnant patients. Don't remove IUD automatically. TOA ≥7 cm → drainage. 72-h reassessment mandatory. Treat partners. HIV + syphilis testing at every STI visit. Single PID episode → ~12% future infertility risk.