(I) Pathogenesis In fact, endometritis is not uncommon in young women, but there are not many cases of pus accumulation in the uterine cavity, because the cervical canal can play a good role in drainage. In postmenopausal women, the level of estrogen decreases, the cervix atrophies, the glandular secretion decreases, the vaginal function decreases, and pathogenic microorganisms invade retrogradely from the vagina, causing adhesions, stenosis or atresia of the cervical canal, which eventually leads to pus accumulation in the uterine cavity. In addition, endometrial cancer invading the cervical canal or cervical cancer, acute or chronic endometritis can lead to cervical canal stenosis or atresia, and if the inflammatory secretions in the uterine cavity cannot drain out or are poorly drained, followed by combined infection, pus accumulation in the uterine cavity can also occur. It is also found that a considerable number of patients with pus in the uterine cavity have chronic pelvic inflammatory disease, diabetes mellitus, etc., or still have birth control devices in the uterine cavity, which indicates that the systemic immune status and local inflammation also play a role in the formation and development of pus in the uterine cavity. 1) Necessary conditions for the development of pus in the uterine cavity: ① pus generation: or pus at the beginning, or non-inflammatory fluid and blood accumulation first, followed by combined infection. (ii) Cervical stenosis and atresia: endometritis is the most direct cause of the development of this disease. (B) Pathogenesis Cervical malignancy, especially after radiotherapy, cervical electrocautery, freezing or cervical conization, severe chronic cervicitis, scar formation caused by vaginitis, and cervical atrophy in elderly women, etc., make the obstructed stagnant secretions not easy to discharge, and the proliferation of germs in cancerous tissues may also lead to cause cervical canal stenosis and obstruction. 1.Blood test The white blood cell count is elevated and the number of neutrophils is increased. 2.Histopathological examination If necessary, scrape the endometrial tissue for pathological examination to find out whether there is malignant lesion. 3.B-type ultrasonography shows an enlarged uterus with a liquid dark area and strong light spots in the uterine cavity. 5.Gynecological examination The uterus is enlarged, soft and painful to touch. There may be significant thickening of parametrial connective tissue, and there may be inflammatory masses of the adnexa. 6.Bacterial culture of pus and drug sensitivity test can be based on the bacterial growth and the results of drug sensitivity test to facilitate the identification of reasonable drugs and the appropriate dose and find out the corresponding treatment plan.