What are the causes of endometriosis?

Endometriosis is a very harmful disease and needs to be treated according to the patient's actual condition. From a clinical perspective, common causes of endometriosis include reflux implantation factors, hematogenous-lymphatic spread, coelomic epithelial metaplasia, immune factors, etc. Only by treating the disease according to these causes can the best effect be achieved.

1. Countercurrent planting factors (20%):

In 1921, Sampson proposed the theory that the endometrium implants along with the retrograde flow of menstrual blood through the fallopian tube. To this day, the theory of retrograde menstruation is still accepted by most people. The basis for this is that viable endometrial cells can be found in the retrograde menstrual blood in the pelvic cavity. Endometriosis in surgical scars is strong evidence for the endometrial implantation theory, but Sampson's theory cannot explain endometriosis outside the pelvic cavity. In addition, iatrogenic dissemination also supports the implantation theory. A typical example is endometriosis in abdominal wall scars after cesarean section, which accounts for about 90% of endometriosis in abdominal wall scars.

2. Hematogenous-lymphatic spread (25%):

Endometrial tissue can metastasize to distant sites through the blood and lymph nodes, but systemic endometriosis should not be so rare. It is difficult to determine whether this is related to the body's immune function.

3. Coelomic metaplasia (5%):

So far, there is no sufficient clinical report and experimental evidence for this theory.

4. Immune factors (18%):

Immune mechanisms play an important role in the occurrence and development of endometriosis. Studies in recent years have shown that the onset of endometriosis may be caused by an imbalance between immunosuppression and immunopromotion, leading to immune loss of control. In the early stages of the disease, the body shows an active immune response. At this time, the number of NK cells and macrophages increases, lymphocyte activity increases, cytotoxicity increases, and multiple pathways are initiated to clear ectopic endometrial fragments. However, in the process of the interaction between harmful factors (such as immunosuppressive factors) released by endometrial tissue and the immune system, the immune system is induced to release a series of feedback factors, which synergistically further inhibit the clearance of ectopic endometrium by immune active cells and reverse the immune system to an immune promotion phenomenon, that is, a series of active factors are released by immune cells to promote the implantation, adhesion, and proliferation of ectopic endometrium. The clinical characteristics and autoantibodies of the disease may be monoclonal activation patterns, indicating that it has the characteristics of an autoimmune disease.