Chapter 11 Pelvic infections
Definition. Pelvic inflammatory disease (PID) is an upper genital tract infection. This includes infection of the uterus, fallopian tubes and other pelvic viscera.
Causes of infection
Risk factors
Microbiology
It is a polymicrobial infection.
Tubal cultures
Table 11.1 lists the microbiological aetiology of PID.
| Aetiology | Incidence |
|---|---|
| Chlamydia trachomatis | 40%–60% |
| Neisseria gonorrhoea | 15%–18% |
| Mycoplasma species | 10%–15% |
| Anaerobic facultative bacteria: Escherichia coli, group B streptococcus (GBS), Bacteroides species, Peptostreptococcus species, Staphylococcus aureus | 30% |
Neisseria gonorrhoea
• gram-negative diplococcus which invades the columnar epithelium; infection usually occurs in the first half of the menstrual cycle
Diagnosis
Definitive diagnosis is by culture.
• Collect microbiological swabs from the endocervix (or posterior fornix if pregnant), urethra, rectum and throat.
• Conduct polymerase chain reaction (PCR) test on endocervical specimens (95% sensitivity, 100% specificity). In women, PCR testing of first pass urine (10–20 mL at least 1 hour after passing urine) is less sensitive (around 50%), and, if positive, should be followed up by collection of further endocervical specimens for PCR and culture, prior to antibiotic therapy. Treatment can be commenced before these repeat results are obtained.
Chlamydia trachomatis
• Its lifecycle has two stages: (a) an infectious and metabolically inactive elementary body which penetrates the cell wall by endocytosis, where it is transformed into (b) the reticulate body, which reproduces by binary fission to form new elementary bodies in the vacuole, which eventually ruptures to release the organism.
• It is the most common notifiable sexually transmitted disease (STD). Incidence is 2.5%–14% in STD clinic patients, 5% in family planning clients and up to 15% in commercial sex workers.
