Differential Diagnoses for Pelvic Inflammatory Disease

Critical Life-Threatening Differentials

Ectopic pregnancy must be ruled out first in any woman of reproductive age with lower abdominal pain and pelvic tenderness, as this represents an immediate threat to life 1, 2, 3
The Centers for Disease Control and Prevention recommends obtaining β-hCG in all women of childbearing potential before initiating PID treatment 4
Consider transvaginal ultrasound if pregnancy test is positive or clinical suspicion is high 1
Acute appendicitis is a surgical emergency that can present with lower abdominal pain and tenderness, typically with right lower quadrant pain 1, 2, 3
If surgical abdomen cannot be excluded, hospitalization is warranted 4

Tubo-ovarian abscess is a complication of PID itself, but requires different management with imaging and possible surgical intervention 4
Suspect tubo-ovarian abscess when there is severe illness, palpable adnexal mass, or failure to improve within 72 hours of antibiotic therapy, and requires transvaginal sonography or other imaging modalities 1, 2, 5

Urinalysis should be obtained to evaluate for pyuria, though white blood cells in urine can support PID diagnosis 6

If cervical discharge appears normal AND no white blood cells are found on wet prep, the diagnosis of PID is unlikely, and alternative causes of pain should be aggressively pursued 1, 2, 7
Mucopurulent cervical discharge with white blood cells on saline microscopy, fever >101°F (>38.3°C), elevated inflammatory markers (ESR, CRP), and laboratory documentation of cervical N. gonorrhoeae or C. trachomatis infection make PID more likely 1, 2, 7, 8
The CDC guidelines state that diagnosis and management of ectopic pregnancy, acute appendicitis, and functional pain are unlikely to be impaired by initiating empiric antimicrobial therapy for PID 1, 2, 3