Chapter 139 Pelvic Inflammatory Disease (PID)
INTRODUCTION
Description: Pelvic inflammatory disease (PID) is a serious, diffuse, frequently multiorganism infection of the pelvic organs that results in significant morbidity.
Prevalence: One percent to 3% of women; most common gynecologic reason for emergency visits for women aged 15 to 44. Roughly 168,000 cases and approximately 70,000 hospitalizations annually.
ETIOLOGY AND PATHOGENESIS
Causes: In roughly one third of cases the causative organism is Neisseria gonorrhoeae alone. One third of cases involve infection with N. gonorrhoeae and additional “mixed” infections with other organisms. The last third of infections result from mixed aerobic and anaerobic bacteria, including respiratory pathogens such as Haemophilus influenzae, Streptococcus pneumoniae, and Streptococcus pyogenes found in up to 5% of patients. Polymicrobial infections are present in more than 40% of patients with laparoscopically proven salpingitis, with one study reporting an average of 6.8 bacterial types per patient. Only approximately 15% of women with cervical N. gonorrhoeae infections develop acute pelvic infections. Orgasmic uterine contractions or the attachment of N. gonorrhoeae to sperm may provide transportation to the upper genital tract. Chlamydia is involved in roughly 20% of patients, with this rate increasing to roughly 40% among hospitalized patients. Infection of the upper genital tract by Chlamydia causes a milder form of salpingitis with more insidious symptoms.
Risk Factors: Multiple sexual partners, uterine or cervical instrumentation, douching. Because many of the anaerobic bacteria found in mixed infections mimic those found in the vagina of patients with bacterial vaginosis, bacterial vaginosis has been considered a risk factor for the development of pelvic infections, but recently published studies suggest that this is not the case. Of cases, 15% occur after instrumentation such as endometrial biopsy, hysterosalpingography, intrauterine contraceptive device placement, or the like.
WORKUP AND EVALUATION
Laboratory: Complete blood count, including differential, white blood cell count, and erythrocyte sedimentation rate. Cervical culture (although there is only a 50% correlation between cervical culture and upper-tract organisms) and Gram staining.
Imaging: Ultrasonography may demonstrate free fluid in the posterior cul-de-sac (supportive but not diagnostic).
Special Tests: Confirmation by laparoscopy should be considered for any patient who does not respond in a timely manner or for whom the diagnosis is uncertain. In 35% of patients no infection is found. (Data indicate that a clinical diagnosis of symptomatic PID has a positive predictive value [PPV] for salpingitis of 65% to 90% compared with laparoscopy.)
