Pelvic Inflammatory Disease: Terminology and Clinical Spectrum
Pelvic Inflammatory Disease (PID) is the umbrella term that encompasses multiple specific anatomic diagnoses and clinical presentations, including endometritis, salpingitis, tubo-ovarian abscess, pelvic peritonitis, and several clinical variants. 1
Anatomic Site-Specific Names
PID can be more specifically defined by the anatomic site(s) of infection:
- Endometritis (or endomyometritis): Inflammation of the endometrium and uterine wall 1
- Salpingitis: Inflammation of the fallopian tubes 1, 2
- Oophoritis: Inflammation of the ovaries 3
- Salpingo-oophoritis: Combined inflammation of fallopian tubes and ovaries 1
- Tubo-ovarian abscess (TOA): Collection of purulent material involving the fallopian tubes and ovaries 1, 2
- Pelvic peritonitis: Inflammation of the peritoneal surfaces within the pelvis 1
- Parametritis: Inflammation of the parametrial tissues 3
Clinical Presentation Variants
The CDC guidelines recognize that PID has a broad clinical spectrum with distinct presentation patterns:
- Acute PID: The classic symptomatic presentation with acute onset of symptoms 1
- Silent PID (or subclinical PID): Asymptomatic infection that may still cause tubal damage 1, 4
- Atypical PID: Presentations with unusual or minimal symptoms 1
- Chronic PID (or PID residual syndrome): Long-standing inflammation with persistent symptoms 1
- Postpartum/postabortal PID: Infection occurring after delivery or pregnancy termination 1
Etiology-Based Nomenclature
Individual cases can also be classified by the causative organism(s):
- Chlamydial endometritis: PID caused by Chlamydia trachomatis 1
- Gonococcal salpingitis: PID caused by Neisseria gonorrhoeae 1
- Nonchlamydial/nongonococcal salpingo-oophoritis: PID caused by other organisms including anaerobes, G. vaginalis, enteric gram-negative rods, and streptococci 1
Important Clinical Context
The term "Pelvic Inflammatory Disease" itself refers to the clinical syndrome resulting from infection involving the uterus, fallopian tubes, ovaries, peritoneal surfaces, and/or contiguous structures. 1 This infection typically results from ascending spread of microorganisms from the vagina and endocervix to the upper genital tract 1, 4.
The polymicrobial nature of PID means that multiple organisms are often involved simultaneously, making it a spectrum disorder rather than a single disease entity 2, 5. This is why the nomenclature emphasizes both anatomic location and clinical presentation patterns rather than relying solely on a single diagnostic term.