1. How does endometriosis occur?
Endometriosis is a common gynecological disease in women. Modern medical research has a variety of theories on the pathogenesis of this disease, among which the endometrial implantation theory is generally accepted and recognized. In addition, the occurrence of endometriosis is also related to the immune function of the body, genetic factors, and environmental factors.
(1) Implantation theory (menstrual blood reflux theory): This theory was proposed by Sampson in the 1920s. The main idea of this theory is that the endometrial fragments shed during menstruation enter the abdominal cavity through the fallopian tubes with menstrual blood reflux and are planted in the ovaries and adjacent pelvic peritoneum. Nowadays, it is found that 80% of women have menstrual reflux, but the actual incidence is still a minority, which indicates that the endometrium planted in the pelvic and abdominal cavity needs certain conditions to grow, namely the immune function system to clear the planted endometrium locally in the pelvic and abdominal cavity. If the endometrium is described as a seed, the pelvic and abdominal plasma membranes are the soil, and both are suitable for the seed to germinate and take root and blossom. Cesarean section uterine and abdominal incision endografts and perineal incision endografts are also the result of endometrial implantation.
(2) Lymphatic and venous dissemination theory: Endometrium can enter the pelvic vein or lymphatic system, and endometriosis occurring in organs far from the pelvic area (nasal cavity, conjunctiva) may be the result of lymphatic or venous dissemination. Clinical evidence of nasal bleeding and conjunctival bleeding during menstruation can also be seen in some women, a phenomenon also known as “inverted menstruation”
(3) The theory of epithelial metaplasia: The ovarian peritoneum and pelvic peritoneum originate from the epithelium of the body cavity, which can metaplasia into the endometrium after repeated stimulation by menstrual blood, hormones or chronic inflammation, forming endometriosis.
2. Why is the incidence of endometriosis increasing?
The incidence of endometriosis is on the rise, with 10% of women of childbearing age, 30% of infertile patients and 50% of patients with dysmenorrhea. The peak age is 25-45 years. Why? We have noticed that pre-menarcheal and post-menopausal women rarely suffer from endometriosis, that pregnancy and breastfeeding inhibit the occurrence of endometriosis, and that the use of contraceptives reduces the occurrence of endometriosis. These phenomena tell us that the occurrence of endometriosis may be related to the changing reproductive patterns of modern women.
(1) Altered menstrual status: tendency to early menarche and late menopause: this has become a phenomenon of concern, with the result of increasing the number of menstrual periods in the female life cycle, that is, increasing the number of backflow of menstrual blood and increasing the risk of endometriosis.
(2) Changing reproductive patterns: modern women generally marry late and have fewer children, most of them having only one child. The number of full-term pregnancies and the duration of breastfeeding are inversely proportional to the incidence of endometriosis. In other words, the incidence of endometriosis decreases when the number of deliveries increases and decreases when the breastfeeding period increases.
(3) Change in contraceptive measures: Modern women’s choice of contraceptive methods is changing, with less use of birth control pills, more IUDs and fewer tubal ligations. In order to reduce the exposure to sex hormones, modern women are using less and less contraceptive pills, and most of them choose IUDs for contraception. Contraceptive pill use is a protective under factor for the development of endometriosis, while IUDs, on the contrary, are a high risk factor for endometriosis.
(4) Estrogen use: Modern women have increased estrogen replacement in order to postpone menopause, or to be “young”, and estrogen is considered to be a contributing factor to endometriosis.
(5) Other factors: Environmental pollution can change the pelvic and abdominal environment and affect local immunity. In addition, the incidence of pelvic inflammatory disease in modern women is also on the rise, and pelvic inflammatory disease can increase the risk of endometriosis.
3. Why is endometriosis unpredictable?
The clinical pathology of endometriosis is unpredictable. Why do some patients with endometriosis have severe menstrual pain while others do not? Why are some patients infertile and others able to achieve fertility? These are all related to the different sites of endometrial implantation, which can present different pathologies and clinical symptoms.
Ovarian endometriosis.
Clinically ovarian endometriosis is the most common, with 80% of patients having lesions involving one ovary and 50% having bilateral ovarian involvement at the same time. In the early stage, purple-brown spots or vesicles are seen on the ovarian surface and in the cortex. As the lesion develops, the ectopic endometrium in the ovary bleeds repeatedly and forms single or multiple cysts, which contain dark brown mucousy old blood, resembling chocolate liquid, hence the name ovarian chocolate cysts.
Characteristics of ovarian chocolate cysts.
(1) Each time the menstrual period comes, the cyst bleeds synchronously once, the pressure inside the cyst rises gradually with time, and the pressure rises to a certain level where small fissures appear in the cyst wall and a small amount of blood leaks. This causes an inflammatory reaction in the abdominal wall and closure of the tissue fibrosis, resulting in adhesion of the ovary to the surrounding tissue and inactivity. This condition is often mistakenly treated as pelvic inflammatory disease. This phenomenon is called incomplete rupture of a chocolate cyst. In the patient’s history there may be: a previous episode of transient pain in the lower abdomen, mostly present during strenuous exercise or sexual intercourse, with emergency medical attention and relief with antibiotics, or on its own without medical attention. If a severe rupture occurs it can cause an acute abdomen and the patient often requires emergency surgery.
(2) Once the rupture occurs, the chocolate cyst shrinks a little, and when the patient is followed up for a follow-up visit, he is often happy that his chocolate cyst has shrunk, but in fact, from a pathological point of view, it is not a reduction but an aggravation of the disease. The cyst will grow slowly over time. Due to the presence of spontaneous rupture, in clinical practice we rarely see larger cysts of more than 10 cm, most of them are about 5 cm. This is called cyst self-limiting.
(3) Most chocolate cysts are fixed or semi-fixed to the pelvic floor because of repeated bleeding and adhesions.
(4) Ultrasound examination also reveals that chocolate cysts have uneven thickness of the cyst wall, separation within the cyst, and reflection of tiny light spots within the cyst.
(5) When the ovaries are involved bilaterally, the two cysts come together in the middle of the pelvis, forming a “kissing pair”.
Pelvic intraperitoneal heterogeneity.
The uterosacral ligament, rectal uterine sockets, and lower posterior uterine wall are also common sites of endometriosis. The lesions have scattered purple-brown blebs or granular scattered nodules. The development of the lesion causes painful intercourse (deep tenderness) in the posterior wall of the uterus and the anterior wall of the rectum, and painful defecation or an increase in the number of bowel movements during menstruation, a phenomenon also known as “urgency”. In severe cases, the ectopic endometrium develops and protrudes into the rectovaginal septum to form deep endometriosis, which makes treatment difficult.
(3) Other endometriosis sites: focal implants can sometimes be seen in the cervix, vaginal vault, fallopian tubes, and bladder. Corresponding clinical symptoms appear, such as bladder implantation can cause periodic hematuria.
4. Why does endometriosis cause abnormal menstruation, dysmenorrhea and infertility?
Menstrual disorders, dysmenorrhea, and infertility are the main clinical symptoms of endometriosis.
(1) Dysmenorrhea: Dysmenorrhea is the most typical symptom of endometriosis. The medical term for this is progressive increase in secondary dysmenorrhea. It starts without pain and slowly develops over time with a gradual increase in dysmenorrhea. It can occur before, during and after menstruation. The initial phase is tolerable, and after several months or years some of the dysmenorrhea worsens requiring painkillers, and the severe phase is so painful that painkillers are increased or even ineffective. The pain is caused by the inflammatory response of the local tissues stimulated by bleeding within the endoheterosis. The increased secretion of prostaglandins from the endometriosis lesion leads to contracture of the uterine muscles and the dysmenorrhea is bound to be more pronounced. After menstruation, the bleeding stops and the pain is relieved. Dysmenorrhea is not only related to the severity of the lesion but also to the site of endometriosis implantation.
(2) Menstrual abnormalities: they can be manifested as excessive menstruation or cycle disorders. Most of the menstrual abnormalities are related to the effect of endometriosis on ovarian function. Patients with endometriosis may experience ovarian dysfunction, such as abnormal ovulation.
(3) Infertility: Patients with endometriosis are often associated with infertility. Infertility occurs in 40-50% of infertile patients. Causes: Endometriosis can often cause adhesions around the fallopian tubes affecting oocyte pick-up; or ovarian lesions affecting ovulation.
(4) Painful intercourse: endometriosis in the rectal fossa and vaginal rectal compartment can cause painful intercourse (deep tenderness), increased bowel movements and pain during menstruation (urgency).
(5) Other: bladder irritation signs: those with endometriosis to the bladder appear to have periodic urinary frequency, painful urination, and hematuria. Endometriosis in the scar of the abdominal wall and umbilicus presents with periodic localized masses and pain.
5. What tests should be done for endometriosis?
In addition to clinical symptoms, the diagnosis of endometriosis requires some necessary tests.
(1) Gynecological examination.
Uterus: Uterus is enlarged, posteriorly positioned, restricted in movement, and nodules can be palpated on the posterior wall. Suggests intrinsic endometriosis (adenomyosis)
Pelvic floor: hard small nodules, such as the size of green beans or soybeans, are often palpable in the sacral ligament, rectal fossa of the uterus, and posterior wall of the cervix, mostly with significant tenderness. They are easily mistaken for malignant tumors.
Ovaries: cysts are often adherent and fixed to the surrounding area and easily misdiagnosed as adnexitis masses.
(2) Ultrasound examination: Ultrasound is currently an effective method to assist in the diagnosis of endometriosis and is mainly used to observe ovarian chocolate cysts, adenomyosis.
Cystic masses with clear or indistinct borders.
Granular fine echogenicity is seen within the cysts. Sometimes there is a denser coarse light dot image in the form of a mixed mass due to concentrated mechanization of the old clot.
The mass is often located on the posterior side of the uterus, and cystic uterine adhesions are seen.
(3) laparoscopy: laparoscopy is the new standard for diagnosis of endometriosis, through which the pelvic cavity can be directly visualized and a clear diagnosis can be made when ectopic lesions are seen, and clinical staging can be performed to determine the treatment plan
(4) Blood tumor-related indexes examination: CA125, CA199, elevated indicates endometriosis activity and is also a high risk factor for malignant transformation, generally not more than 200IU/L.
6.Can endometriosis become cancerous?
In a few cases, lesions will occur, and the malignancy rate is 3%. The biological behavior of endometriosis is very similar to that of malignant tumors, such as infiltrative growth, implantation and metastasis, and recurrence after surgery, but endometriosis is a benign disease. To use an analogy, endometriosis is like a well-behaved but very naughty child who sometimes gets into mischief. In addition, gynecological examination, ultrasound examination and blood tumor-related index examination are sometimes difficult to distinguish from malignant tumor.