Endometriosis is a common gynecological disease, which is a serious cause of infertility in women. Find out the cause, symptoms, and treatment of this disease.
What is Endometriosis?
Endometriosis is a painful disorder of the female reproductive organ, the uterus. In this disease, the inner lining of the uterus- called the endometrium – which normally lines the insides of the uterus, grows in other locations outside of it.
To understand endometriosis, it is important to understand the basic structure of the female reproductive tract.
The uterus is a shaped like an inverted triangle, with the apex as the cervix opening into the vagina, and its two angles opening into the fallopian tubes. The fallopian tubes, in turn, open into the space housing the pelvic organs, the pelvic cavity. Just at the tip of the opening of each fallopian tube lies the ovary, one on each side. The ovary releases eggs during ovulation, which enters into the fallopian tube till fertilization occurs.
The uterus has three walls – the inner lining called the endometrium, the middle muscular wall called the myometrium, and the outer coating called the perimetrium. The endometrial lining spreads to other tissues in the pelvis and abdomen in endometriosis.
In endometriosis, the endometrial tissue grows in other pelvic organs such as the ovaries, fallopian tubes, vagina, and cervix. Rarely, the endometrial tissue implants in abdominal organs such as the kidneys, gallbladder, stomach, and the lower part of the large intestine called the rectum. However, the ovary is the commonest site for abnormal implantation of the endometrial tissue in endometriosis.
The problem with this abnormal implantation of the endometrium is that it continues to undergo the cyclical changes that occur in the menstrual cycle – it thickens and sheds as menstrual blood with each cycle. Therefore, the displaced endometrial tissue in all the abnormal locations also thickens and sheds within each menstrual cycle.
However, unlike in the uterus, the shed tissue has no exit in these other organs. It remains trapped in these tissues, causing severe symptoms.
Endometriosis typically affects women of reproductive age, with a prevalence rate of about 35% in infertile women. Endometriosis with abnormal sites in the pelvis usually occurs in women aged 35 to 30 while spread of endometrial tissue to sites outside the pelvis typically occurs in women aged 35 to 40 years
Women who have not reached puberty do not have a risk of this disease and adolescents who have it usually have other structural abnormalities of the uterus. Menopause usually causes the disease to resolve, therefore menopausal and postmenopausal women often do not usually have the disease.
Signs and Symptoms of Endometriosis
About one-third of women who have endometriosis show no symptoms, however, pelvic pain associated with the menstrual period is the commonest symptom women with endometriosis experience. Typically, symptoms of endometriosis may reflect the site of implantation.
Symptoms of endometriosis include:
Painful Periods: This is also called dysmenorrhea and it may begin before the period starts and end a few days after menses stops. Painful periods may also occur with severe back and abdominal pain.
The severity of the pain in endometriosis does not reflect the severity of the disease. Some women with severe disease may experience little to no pain, while women with mild endometriosis may present with severe pelvic pain.
Heavy menses: Women with endometriosis usually experience heavy menstrual flow or bleeding in between periods, because of the density of the endometrial tissue.
Pain during sexual intercourse: Women with endometriosis usually experience pain during sexual intercourse, and this is often worst before the menstrual period occurs. Painful intercourse may be due to inflammation of the ligaments in the uterus caused by the external deposition of the endometrial tissue.
Pain with defecation or urination: This may occur if the endometrial tissue implants in the bladder or colon respectively, in which case passing urine and bowel movements trigger pain. The pain may be cyclical, occurring only during the time of menstruation when the endometrial lining sheds.
Pain during exercise: Women with endometriosis usually experience pain when they exercise. This results from the movement of abdominal and pelvic organs scarred by endometrial tissue.
Other Symptoms: Other non-specific symptoms that occur in endometriosis include nausea, fatigue, diarrhea, bloating, constipation, and vomiting.
These overlapping symptoms of the urinary tract and digestive tract cause diagnostic confusion such that endometriosis is usually mistaken for other diseases, such as inflammatory bowel syndrome or a urinary tract infection.
Causes of Endometriosis
The exact cause of endometriosis is not well established; however, some theories have been postulated to explain how the disease occurs. These include the following:
Retrograde menstruation explains that menstrual blood, which contains endometrial tissue and debris, flows back into the fallopian tubes and the pelvic cavity, instead of out the body through the vagina.
These endometrial tissue cells, in turn, adhere to the surface of the pelvic organs, remaining under the influence of the female reproductive hormones, progesterone and estradiol, shedding with each menstrual cycle and bleeding on the organs they adhere to.
Transformation of Peritoneal Cells
This theory, also called the induction theory, explains that the cells that line the peritoneum – a bag of sac that houses the pelvic and abdominal organs – transform to form the endometrial cells, spontaneously or under the influence of hormones and immune cells. This transformation is called metaplasia.
Embryonic cell Transformation
Embryonic cells are cells in their early stages of development, which can transform into other types of cells. Under the influence of female reproductive hormones, embryonic cells may transform into endometrial cells during puberty, implanting in any tissue they are in.
Scientists have suggested that some women may have a genetic predisposition to this disease. Several studies reveal that first-degree relatives of women with endometriosis are more likely to develop the disease, supporting this theory.
Spread of the endometrial cells through the body’s fluid system – the blood and lymphatics – may explain some cases of endometriosis. This mode of spread of the disease explains why endometrial tissue may implant in distant sites such as the nose or lungs.
Dissemination and deposition of the endometrial tissue may also occur following some surgical procedures such as a cesarean section or other gynecological procedures. This is called surgical scar implantation, where the endometrial cells may attach to the abdominal incision made by the surgeon.
This theory explains that women with an impaired immune function that demonstrate an inability to recognize “foreign” endometrial cells in abnormal sites may develop endometriosis. If the immune function were intact, a tissue growing in a wrong location will be destroyed and disposed of.
Risk Factors of Endometriosis
Some factors place some women at a greater risk of endometriosis than others. These include:
- Nulliparity, or having never given birth.
- Early age at onset of period.
- Late onset of menopause
- Short menstrual cycle length (typically less than 27 days)
- Long duration of menstrual flow (longer than 7 days)
- Heavy menstrual bleeding.
- A family history of endometriosis
- Delayed childbearing
- Structural abnormalities in the uterus
- High exposure to estrogen.
- Being underweight or having a low body mass index.
- Excessive alcohol consumption
- Any medical condition obstructing the flow of menstrual period out the body.
Endometriosis typically develops many years after a woman begins to see her period. Pregnancy temporarily relieves the signs and symptoms, but menopause leads to a full resolution of the symptoms. However, postmenopausal women who take estrogen replacement may still experience symptoms of endometriosis.
Complications of Endometriosis
Complications of endometriosis include:
Infertility is the main complication of endometriosis. Approximately one-half of women with endometriosis have difficulty achieving conception.
For conception or pregnancy to occur, as explained above, an egg must be released from the ovary, which then moves to the fallopian tube to be fertilized by a sperm cell. Upon fertilization of an egg, the resulting embryo implants in the uterus after a few days. Endometriosis may block the tube, impairing sperm movement or transport of egg in the tube, preventing fertilization.
However, infertility does not always occur in women with infertility. Women with mild to moderate disease may conceive and carry the pregnancy to term. Endometriosis is one component of a vicious cycle therefore: delayed pregnancy increases one’s risk of endometriosis, which in turn, increases a woman’s risk of infertility.
Chronic pelvic pain
Pelvic pain which lasts six months or longer is a common complication of endometriosis. Due to the implantation of endometrial tissue in pelvic organs and ligaments of the uterus, women with endometriosis experience moderate-to-severe pain during each menstrual cycle. The pain may be so discomforting, impairing daily function and reducing a woman’s quality of life.
Ruptured Ovarian Cysts and Cancer
Endometriosis implanted in the ovary may cause structural defects such as cysts which may rupture causing severe pain and internal bleeding. In addition, endometriosis increases a women’s risk of developing ovarian cancer in the future, although this risk is relatively low.
However, women with endometriosis have an increased risk of another type of gynecological cancer called endometriosis-associated adenocarcinoma.
Complications related to Site of Involvement
Endometriosis may involve sites outside the pelvis, such as the lungs, pleura, bladder, kidneys, and gastrointestinal tract causing complications such as bowel obstruction, rectal bleeding, and anemia.
Diagnosis of Endometriosis
There are a number of ways doctors can diagnose endometriosis, however, it starts with a clinical examination. While it is not possible to detect endometriosis during physical examination, your doctor may be able to feel for concurrent abnormalities such as an ovarian cyst.
Imaging techniques are the mainstay of diagnosing endometriosis. These radiological techniques include:
Ultrasound scanning uses high-frequency sound waves to create images of organs or tissues in the body. The ultrasound scan through a device called a transducer or probe sends high-frequency sound waves through the area it is pressed against to create images of the inside of the body.
Although doctors cannot definitely tell that you have endometriosis through an ultrasound scan, they can detect features of endometriosis such as simple or complex cysts, called endometriomas, in the organ of deposition.
Your doctor may evaluate you using a scan with its probe passed through the vagina (transvaginal ultrasound scan) or through the rectum (endorectal ultrasound).
Magnetic Resonance Imaging and Computerized Tomography (CT) Scanning
Magnetic resonance imaging (MRI) is an imaging technique that uses magnetic and radio waves to create images of structures within the body. MRI helps doctors determine the exact location, number, and sizes of endometrial deposits in the body.
MRI is particularly useful in detecting endometriosis involving the rectum. It is also more effective in detecting pelvic growths than an ultrasound scan.
CT scanning uses ionizing radiation to create images of the structures within the body. It usually shows a non-specific appearance of endometriomas in women with endometriosis, making it an unreliable diagnostic method for evaluating endometriosis.
Laparoscopy and Biopsy
Laparoscopy and biopsy is a procedure in which a surgeon views and takes a sample from an organ or tissue inside your abdomen through a long slender device, called a laparoscope, passed through a small incision in your abdomen. Through this device, doctors pass other slender surgical instruments to perform the procedure.
Laparoscopy is the primary method of diagnosing endometriosis. This is because the doctor can directly view all the organs in the pelvis and abdomen and see the presence of abnormal tissues implanted on any of them. Samples of these tissues are then obtained with a biopsy needle and viewed under a microscope to confirm if they are endometrial tissue.
Treatment of Endometriosis
Your doctor may treat endometriosis with drugs or surgically. The treatment approaches he or she will choose depending on your preference as well as the severity of the disease. However, conservative treatment using medicines is often the initial method for treating endometriosis. Surgery is recommended only when the conservative approach fails or the disease is severe.
Medications used in treating Endometriosis
Medicines doctors prescribe for managing endometriosis include pain medications and hormonal drugs.
Your doctor may recommend over-the-counter pain medications such as non-steroidal anti-inflammatory drugs, including ibuprofen and meloxicam. Your doctor may recommend stronger analgesics such as opioids if the pain does not respond to these mild analgesics.
Doctors recommend hormone therapy for treatment of endometriosis because these hormones interrupt a woman’s menstrual cycle, inhibiting the cyclical thickening and shedding of the endometrial tissue, therefore preventing the growth and implantation of the endometrial tissue in other organs.
Although hormone therapy does not lead to a full resolution of the disease, it may cause significant improvement of symptoms.
Some hormonal therapies for endometriosis include:
Birth Control Pills
Birth control pills, as well as contraceptive patches and vaginal devices, may help to improve the disease. These medicines release hormones that interfere with a woman’s menstrual cycle, preventing the buildup and shedding of the endometrial tissue in each cycle.
Using these hormonal contraceptives may, therefore, reduce or eliminate the pain of endometriosis and also lead to a reduction or loss of menstrual flow.
Gonadotropin-Releasing Hormone Agonists and Antagonists
Gonadotropin-releasing hormone is secreted by the hypothalamus in the brain to stimulate the release of gonadotropins from the pituitary glands. Gonadotropins are hormones that stimulate the ovary to produce estrogen and release eggs. Estrogen causes endometrial tissue to grow.
If the gonadotropin-releasing hormone is inhibited, estrogen levels in the blood will drop, causing the endometrial tissue to shrink. The agonists of this hormone, such as Goserelin and leuprolide suppress the production of this hormone, preventing the release of estrogen, while the antagonists such as Elagolix directly block the effects of the hormone.
Examples of progestin therapies include progestin pills, intrauterine contraceptive device, injectable contraceptive, and implantable contraceptive. Progestin thins the endometrial lining, preventing growth and spread of the endometrial tissue to external structures.
Aromatase inhibitors are a group of medicines that prevent the production of estrogen in tissues. As estrogen levels reduce, the endometrial tissue shrinks, preventing its growth and spread in other tissues.
Invasive treatment is often considered if medicines fail to improve the symptoms or if symptoms and complications of the disease are severe.
Your doctor may consider surgery as a conservative treatment for endometriosis to help you get pregnant. Doctors perform this surgery to remove the endometrial tissue from its abnormal sites while preserving your uterus and ovaries to help you achieve conception.
This procedure may be performed using a laparoscope described above or through traditional open surgery with large incisions in your abdominal wall. After removing these endometrial implants surgically, your doctor may recommend continuing with pain medications and hormone therapies to improve symptoms.
Radical Surgery: Hysterectomy with Bilateral Oopherectomy
Hysterectomy is the surgical removal of the uterus while oophorectomy is the surgical removal of both or one ovary. Surgical removal of the uterus and ovaries was once considered the main treatment of endometriosis, but novel methods are focused on removal of the implanted endometrial tissue as the main treatment of the disease.
Endometriosis is a common cause of chronic pelvic pain among women of reproductive age. Although the cause of this disease is unclear, it is characterized by deposition of the endometrial lining of the uterus in sites outside the uterus, causing severe complications such as infertility. With early and aggressive treatment, the symptoms may resolve.