Endometriosis is one of the most common female diseases. It occurs in every ninth woman of childbearing age. In the world, they number about 190 million.
The nature of this disease is that the tissue, similar to the lining of the uterus (endometrium), grows outside the uterus. These endometriosis foci can appear in the ovaries, the digestive and urinary organs, the lungs and even in the brain (such a rare case was reported in 1993). They, as well as the mucous membrane of the uterus, undergo the usual changes during the menstrual cycle of a woman and cause the development of pain syndrome, general fatigue and, often, female infertility, as well as a number of other painful manifestations.
Symptoms and diagnosis
The main symptoms are cramping pains in the lower abdomen before or during menstruation (dysmenorrhea), pain during defecation or urination (dysuria), recurring blood in the stool or urine, pain during sexual intercourse, back and spine ache, sometimes even with irradiation to the lower extremities. These conditions usually depend on the phase of the menstrual cycle. Chronic fatigue, irritability, migraines, mood swings are also often observed. As already mentioned, the disease is often accompanied by infertility.
The diagnosis can be made merely with the help of an ultrasound examination. An MRI examination helps to clarify it. Sometimes diagnostic laparoscopy is required, i.e., a minimally invasive surgical procedure in the abdominal cavity.
Available therapy options
Typically, endometriosis is a chronic condition with recurrences. Today, there are no criteria to assess how the disease will proceed in each individual case.
No radical methods to cure abnormal endometrial overgrowth have been developed so far. Usually this diagnosis implies hormonal therapy, which allows patients to get rid of complaints completely, or significantly reduce them. In some cases, surgery may be necessary.
What is the cause of endometriosis?
As of now, there is no definite answer to this question. There are many theories about it. The most common are:
- The implantation or transplantation theory. It claims that when menstrual blood is retrogradely shed through the ovaries into the abdominal cavity, the cells of the uterine mucosa get from the uterine cavity to other parts of the body.
- The metaplasia theory proceeds from the fact that uterine mucosal cells in endometriosis foci arise directly in situ (e.g. in the ovaries or intestines, etc.). For reasons not yet known, they can arise from cells of those tissues that develop from the same cell line as the cells of the uterine mucosa during intrauterine development of the fetus.
Other assumptions are the theory of immune system disorders and the hormonal theory.
Potential key to solving the puzzle: genetics.
Genetics (although there is no evidence of direct inheritance of this disease) has been given increasing importance among the mechanisms of the appearance and development of endometriosis in recent years. In this regard, new data have emerged that have attracted specialists’ close attention.
An international team of scientists consisting of 24 research groups has brought to light the results of the largest to this date study on the genetic causes of endometriosis.
The report was published in the specialized journal Nature Genetics.
The researchers compared a group of 60,674 European and East Asian women with endometriosis and a control group of 701,926 women without the disease.
Before this large-scale scientific project, experts knew of 17 genetic zones associated with endometriosis. The research team, however, found that there were as much as 42 of them.
In addition, the scientists found that certain genetic risk factors for endometriosis are also interrelated with other diseases. Thus, reliable genetic interdependencies were established between endometriosis and 11 types of pain conditions, among them - migraines, back pain, etc., as well as inflammatory diseases, such as asthma and osteoarthritis. This could be an indication of the nervous system “hypersensitivity” common of these conditions.
Currently, the path to a correct diagnosis often runs into years. With detailed data on genetic risk factors, this process could be greatly accelerated. Also, the established patterns may enable the development of new, more effective therapies for endometriosis.
- Fonseca, M.A.S., Haro, M., Wright, K.N. et al. Single-cell transcriptomic analysis of endometriosis. Nat Genet 55, 255–267 (2023). https://doi.org/10.1038/s41588-022-01254-1
- S2k-Leitlinie Endometriose: Diagnostik und Therapie der Deutschen Gesellschaft für Gynäkologie und Geburtshilfe (DGGG). In: AWMF online (Stand 8/2013)