Diagnostic Tests and Treatment for Pelvic Inflammatory Disease (PID)
The diagnosis of PID requires a low threshold for suspicion in sexually active women with pelvic pain, and treatment should include broad-spectrum antibiotics covering Neisseria gonorrhoeae, Chlamydia trachomatis, and anaerobes to prevent long-term reproductive complications. 1
Diagnostic Approach
Minimum Diagnostic Criteria
- Empiric treatment should be initiated in sexually active women at risk for STDs if they present with either:
- Uterine/adnexal tenderness OR
- Cervical motion tenderness 1
Additional Supporting Criteria
- Oral temperature >101°F (>38.3°C) 1
- Abnormal cervical or vaginal mucopurulent discharge 1
- Presence of white blood cells (WBCs) on saline microscopy of vaginal secretions 1
- Elevated erythrocyte sedimentation rate (ESR) 1
- Elevated C-reactive protein (CRP) 1
- Laboratory documentation of cervical infection with N. gonorrhoeae or C. trachomatis 1
Most Specific Diagnostic Tests
- Endometrial biopsy with histopathologic evidence of endometritis 1
- Transvaginal sonography or MRI showing thickened, fluid-filled tubes with or without free pelvic fluid or tubo-ovarian complex 1, 2
- Laparoscopic abnormalities consistent with PID 1
Important Clinical Considerations
- Many PID cases go unrecognized because symptoms may be mild or nonspecific (abnormal bleeding, dyspareunia, vaginal discharge) 1, 3
- If cervical discharge appears normal and no WBCs are found on wet prep, PID is unlikely 1
- Cervical cultures or non-culture tests for N. gonorrhoeae and C. trachomatis should be obtained in all suspected cases 1, 3
- CT imaging is often the first imaging performed due to nonspecific clinical manifestations and can show thickening of uterosacral ligaments, pelvic fat stranding, reactive lymphadenopathy, and pelvic free fluid 2
Treatment Approach
Principles of Antibiotic Therapy
- Treatment regimens must provide empiric, broad-spectrum coverage of likely pathogens 1
- Coverage should include N. gonorrhoeae, C. trachomatis, anaerobes, gram-negative facultative bacteria, and streptococci 1
- Treatment should be initiated as soon as the presumptive diagnosis is made 1
- All regimens should be effective against N. gonorrhoeae and C. trachomatis, even with negative endocervical screening 1
Recommended Antibiotics
- For PID treatment, FDA-approved antibiotics include:
Treatment Considerations
- Azithromycin may improve cure rates in mild-moderate PID compared to doxycycline based on recent evidence 6
- Adding metronidazole (nitroimidazole) to treatment regimens shows little to no difference in cure rates but ensures anaerobic coverage 6
- Clindamycin plus aminoglycoside regimens are comparable to cephalosporin regimens for severe PID 6
Clinical Pitfalls and Caveats
- Diagnostic challenges: No single historical, physical, or laboratory finding is both sensitive and specific for PID diagnosis 1, 2
- Risk of underdiagnosis: Maintain a low threshold for diagnosis due to potential reproductive health damage even from mild cases 1, 7
- Differential diagnosis: Important to rule out ectopic pregnancy, acute appendicitis, and functional pain before initiating treatment 1, 2
- Follow-up: If no clinical improvement occurs within 48-72 hours, reconsider alternative diagnoses (appendicitis, endometriosis, ruptured ovarian cyst, adnexal torsion) 1, 8
- Long-term complications: Without proper treatment, PID can lead to tubal infertility, ectopic pregnancy, chronic pelvic pain, and tubo-ovarian abscess 3, 7, 8
- Chlamydia coverage: Cephalosporins have no activity against Chlamydia trachomatis, so appropriate antichlamydial coverage must be added when using these antibiotics 4, 5