Endometritis, typically presenting in sexually active women, characteristically shows an irregular thickening and enhancement of the endometrium on T2-weighted MRI images with neutrophilic infiltrates seen acutely and plasma cell infiltrates seen chronically.
Description
Endometritis is an inflammatory condition of the endometrium, the inner lining of the uterus, typically caused by an infection. It is common in sexually active women, particularly those with a history of sexually transmitted infections or procedures involving the uterus. Both acute and chronic forms of endometritis exist, with the latter often leading to recurrent symptoms and potential fertility issues.
Pathogenesis
The pathogenesis of endometritis often involves ascending bacterial infection from the vagina or cervix, most commonly due to sexually transmitted pathogens. In other instances, it can be caused by non-sexually transmitted bacteria, particularly after childbirth, miscarriage, or uterine procedures. Chronic endometritis is typically marked by persistent infection and inflammation, often due to unresolved acute endometritis or subclinical infections.
Subtypes
- Acute Endometritis: Rapid onset, often related to recent childbirth or uterine procedure.
- Chronic Endometritis: Persistent or recurrent, often associated with infertility and recurrent miscarriage.
Epidemiology, Risk Factors & Associations
- Sexually active women (Increased risk with multiple sexual partners)
- Recent childbirth, particularly if complicated (Up to 5% of vaginal deliveries, 15% of caesarean deliveries)
- Recent uterine procedures (Dilatation and curettage, endometrial biopsy, etc.)
- Presence of an intrauterine device
- History of pelvic inflammatory disease or sexually transmitted infections
Clinical Features
- Lower abdominal pain or pelvic pain
- Fever and malaise (particularly in acute endometritis)
- Abnormal uterine bleeding
- Purulent vaginal discharge
- Pain during sexual intercourse
Complications
- Infertility or decreased fertility (in chronic endometritis, up to 40% of women with unexplained infertility)
- Recurrent pregnancy loss
- Progression to pelvic inflammatory disease
- Sepsis or septic shock (in severe or untreated acute endometritis)
Pathological Features
Histopathology
- Macroscopic: Thickened, hyperaemic endometrium in acute phase; normal to minimally thickened in chronic.
- Microscopic: Neutrophilic infiltrate in the endometrial epithelium (acute), plasma cell infiltrate (chronic).
Serology
- Evidence of causative organism (chlamydia, gonorrhoea, group B streptococcus etc.)
Biochemistry
- Increased inflammatory markers (CRP, ESR)
Radiological Features
General Features
- Thickened, irregular endometrium with enhancement post contrast (particularly notable in acute phase)
CT
- Non-contrast: Non-specific findings, may show thickened endometrium
- Contrast-enhanced: Enhanced thickened endometrium
MRI
- T1WI: Endometrium is hyperintense compared to myometrium.
- T2WI: Irregular thickening and enhancement of the endometrium.
- T1 C+: Enhancement of thickened endometrium.
- DWI/ADC: Diffusion restriction may be seen due to inflammation.
US
- B-mode: Endometrial thickening with irregular echogenicity.
- Colour: Increased vascularity may be seen in acute phase.
NM
- PET FDG: Not typically indicated
Grading and Staging
There is no specific grading or staging system for endometritis.
Diagnosis
Diagnosis is typically clinical, supported by laboratory and imaging findings. Endometrial biopsy with histopathology is the gold standard.
Differential Diagnosis
- Endometrial polyps: Can also cause endometrial thickening, but generally more focal with a vascular pedicle.
- Endometrial hyperplasia or carcinoma: Generally in older, postmenopausal women with risk factors such as obesity and unopposed oestrogen. Typically presents with postmenopausal bleeding.
- Submucosal fibroid: Shows well-defined borders and typical whorled appearance of fibroids on imaging.
Management
Management typically involves antibiotics targeting the likely or identified pathogen. For women with chronic endometritis related to infertility or recurrent pregnancy loss, treatment can result in improved fertility outcomes. In some cases, surgical management (D&C, hysteroscopy) may be needed.