What is Endometritis
Endometritis is an infection or inflammation of the endometrium (the inner lining of the uterus) that occurs in two distinct clinical forms: acute endometritis (typically postpartum) and chronic endometritis (often associated with infertility). 1
Acute Postpartum Endometritis
Postpartum endometritis is the most common cause of postpartum fever, particularly after cesarean delivery, and represents a polymicrobial infection caused by vaginal organisms that invade the endometrial cavity during labor and delivery. 2, 3
Clinical Presentation
- High fever (≥101°F or >100.4°F on more than two occasions >6 hours apart) occurring after the first 24 hours post-delivery and up to 10 days postpartum 1
- Abdominal pain and uterine tenderness 1
- Foul-smelling lochia (vaginal discharge) 1
Microbiology
- Usually a multi-organism syndrome involving both anaerobic and aerobic bacteria from the normal cervicovaginal flora 1, 3, 4
- The infection involves organisms inoculated into the uterus during labor and delivery 3, 4
- In rare cases (particularly in HIV-positive patients), viral causes including herpes simplex virus and cytomegalovirus should be considered if antibiotic therapy fails 5
Risk Factors
- Cesarean delivery increases the risk 5-7 times, especially if performed after onset of labor or rupture of membranes 2
- Most commonly seen in patients with unplanned cesarean section due to inability to introduce prophylactic antibiotics quickly 1
- Prolonged rupture of membranes and prolonged labor 6
Imaging Findings
- On CT, endometritis appears as thickened heterogeneous endometrium with fluid, gas, and debris within the uterine cavity 1
- This is a clinical diagnosis; imaging findings are nonspecific 1
Chronic Endometritis
Chronic endometritis is a silent disease characterized by persistent inflammation of the endometrium, typically diagnosed during workup for secondary amenorrhea or infertility. 7
Key Features
- Microscopic examination shows micro-abscess formation and neutrophil invasion in the superficial endometrium 7
- An important cause in developing nations is tuberculosis 7
- Associated with poor reproductive outcomes and infertility, affecting approximately 50% of patients with endometriosis-related chronic inflammation 8, 7
Critical Distinction: Not Endometriosis
Do not confuse endometritis (infection/inflammation of the endometrium) with endometriosis (endometrial-like tissue outside the uterus causing pelvic pain and infertility). 8 These are completely different disease entities with different pathophysiology, presentations, and treatments.
Diagnostic Approach for Postpartum Endometritis
Patients with suspected pelvic inflammatory disease or postpartum endometritis should be tested for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and HIV. 1
Laboratory Evaluation
- Blood cultures, complete blood count with differential, metabolic panel, and lactate level should be obtained before antibiotics if the patient is hemodynamically stable 2
- Bacterial cultures from nonaseptically collected specimens (endocervical or D&C) have limited utility 1
Treatment Principles
The combination of clindamycin and gentamicin is the appropriate first-line treatment for postpartum endometritis, with 93.7% of cases responding to initial antibiotics. 2, 3
Antibiotic Selection
- Regimens with good activity against penicillin-resistant anaerobic bacteria are superior to those with poor activity (fewer treatment failures: RR 1.94, fewer wound infections: RR 1.88) 3
- Once-daily gentamicin dosing has fewer treatment failures compared to thrice-daily dosing 3
- Following clinical improvement with intravenous therapy, additional oral antibiotic therapy has not been proven beneficial 3
Timing
- Empirical antibiotics should be initiated within 1 hour if the patient presents with hemodynamic instability, septic shock, oxygen saturation <92%, evidence of organ dysfunction, altered mental status, or lactate ≥4 mmol/L 2