From the Guidelines
Endometriosis is a chronic inflammatory disease characterized by the growth of endometrial-like tissue outside the uterus, leading to symptoms such as pelvic pain, dysmenorrhea, dyspareunia, and infertility, primarily due to retrograde menstruation, coelomic metaplasia, lymphatic/vascular dissemination, and stem cell involvement, as well as hormonal, immune, and genetic factors. The pathophysiology of endometriosis involves the implantation of endometrial-like tissue on pelvic organs and peritoneum, which responds to hormonal stimulation, particularly estrogen, causing cyclical bleeding, inflammation, and pain 1. The body's immune response to these implants is dysfunctional, with increased macrophages, cytokines, and growth factors promoting lesion growth and angiogenesis, and prostaglandins contributing to pain and inflammation 1.
Some key points to consider in the pathophysiology of endometriosis include:
- The role of retrograde menstruation, where menstrual tissue flows backward through the fallopian tubes, in the development of endometriosis 1
- The involvement of coelomic metaplasia, where peritoneal cells transform into endometrial-like cells, in the pathogenesis of endometriosis 1
- The impact of hormonal stimulation, particularly estrogen, on the growth and maintenance of endometrial-like tissue outside the uterus 1
- The contribution of genetic factors, with first-degree relatives having a 7-10 times higher risk of developing endometriosis 1
- The complex interplay of hormonal, inflammatory, and immune factors in creating a chronic inflammatory condition with symptoms including pelvic pain, dysmenorrhea, dyspareunia, and infertility 1
Overall, the pathophysiology of endometriosis is complex and multifactorial, involving a combination of hormonal, immune, and genetic factors, and leading to a range of symptoms and clinical manifestations. The most recent and highest quality study, published in 2024, provides the most up-to-date understanding of the pathophysiology of endometriosis, highlighting the importance of considering the complex interplay of factors involved in the development and maintenance of this chronic inflammatory disease 1.
From the Research
Pathophysiology of Endometriosis
The pathophysiology of endometriosis is characterized by the growth of ectopic endometrium outside the uterus, which responds to hormonal stimuli and develops internal bleeding, inflammation, and fibrosis 2, 3. This leads to chronic and often debilitating cyclic pain and infertility. The endometrial-like tissue outside the uterus causes menstrual disorders, chronic pelvic pain, and infertility 4.
Key Features
- The ectopic endometrium responds to fluctuating levels of hormones, leading to monthly bleeding of the cysts, followed by inflammation and scarring 2.
- The disease involves pelvic organs, but can also extend to distant locations in the body 3.
- Hormones, immunologic status, and genetic factors may play a role in the pathogenesis of endometriosis 3.
- Endometriotic lesions can cause systemic effects, including metabolic disorder, immune dysregulation, and cardiovascular diseases 4.
Theories of Pathogenesis
Several theories have been proposed to explain the pathogenesis of endometriosis, including:
- Retrograde menstruation
- Celomic metaplasia
- Embryologic rests
- Lymphovascular spread 3
Clinical Presentation
Women with endometriosis may experience a highly variable range of non-specific signs and symptoms, including pelvic pain, dyspareunia, dysmenorrhea, and infertility 2, 5. The disease is often misdiagnosed, partly because its signs and symptoms can easily be attributed to more common conditions that cause pelvic pain in women, resulting in delayed diagnosis and treatment 5.