Endometriosis is a condition where tissue similar to the lining of the uterus grows outside of the uterus, most commonly on the ovaries, fallopian tubes, and tissue around the uterus. This tissue responds to hormones in the same way the tissue lining the uterus does – it thickens, breaks down, and bleeds each month. Because this tissue has no way to exit the body, it becomes trapped, causing inflammation, scar tissue formation, and adhesions.
The most common symptoms of endometriosis include painful periods, pelvic pain, pain during or after sex, excessive bleeding, infertility, fatigue, and digestive issues. However, some women have no symptoms at all. Endometriosis affects an estimated 1 in 10 women of reproductive age.
One question that often comes up is whether endometriosis starts suddenly or develops slowly over time. In this article, we will examine the current theories on the development and progression of endometriosis and whether there is evidence that it can begin abruptly.
Theories on the origin of endometriosis
There are several theories about where endometriotic tissue comes from and how it spreads in the body:
Retrograde menstruation
The most widely accepted theory is that endometriosis is caused by retrograde menstruation, where some of the endometrial tissue backs up through the fallopian tubes and into the pelvic cavity during menstruation. This tissue then implants and grows on the pelvic structures. However, while most women get some degree of retrograde menstruation, not all develop endometriosis.
Transformation of peritoneal cells
Some research suggests that peritoneal cells in the pelvic cavity could transform into endometrial cells under certain conditions, such as hormonal changes. These cells may then form endometriotic lesions.
Embryonic cell rests
During embryonic development, some endometrial cells may migrate abnormally and become deposited in unusual locations. These displaced cells are called embryonic cell rests. Under certain conditions, these cell rests could develop into endometriotic lesions later in life.
Lymphatic or vascular spread
Endometriosis may be able to spread through the lymphatic system or blood vessels from the uterus to distant areas.
Surgical scar implantation
Endometriosis can rarely occur in surgical scars, likely due to endometrial cells implanting in the scar tissue.
Progression theories
While the origin theories try to explain where the abnormal tissue may come from initially, there are also several theories that look at how endometriosis could progress:
Adhesion formation
As endometriotic tissue irritates surrounding tissue, it can cause inflammation and scar tissue called adhesions. Adhesions may facilitate the spread of endometriosis to other areas.
Triggering by hormones
Fluctuating hormone levels, especially estrogen, may promote the growth and inflammation of endometriosis. This likely fuels the progression.
Altered cell function
Researchers have found differences in gene expression, progesterone resistance, and other functional changes in endometriotic cells compared to normal endometrial cells. These changes may allow the cells to survive outside of the uterus.
Immune system dysfunction
Some researchers believe problems with immune surveillance could allow endometrial cells to implant and grow abnormally. Endometriosis may be able to evade the immune system.
Environmental toxins
Exposure to certain environmental toxins like dioxin has been proposed as a potential contributor to the development and progression of endometriosis, but this link is still being studied.
Evidence that endometriosis can begin abruptly
Given these varied theories on how endometriosis originates and spreads, is there evidence that endometriosis can actually begin suddenly? Here is what the research shows:
Onset after menarche or pregnancy
Many patients report that their painful symptoms began shortly after starting their period for the first time or after a pregnancy. One study found 75% of individuals recalled the sudden onset of symptoms after menarche. While the endometriosis may have already been present before symptoms began, this suggests it was asymptomatic and something abruptly triggered symptoms.
Onset after cervical trauma
Some case reports have found the sudden onset of endometriosis shortly after trauma to the cervix or uterus. It is hypothesized the trauma facilitated the spread of endometrial cells outside the uterus.
Rapid onset in animal models
In animal studies, autologous transplantation of endometrial tissue leads to lesion formation and symptoms of endometriosis rapidly within 4-12 weeks. This supports the idea that endometriosis can become symptomatic quickly after tissue transplantation.
Sudden spread to surgical scars
There are many cases of endometriosis spreading quickly to surgical scars after procedures like cesarean sections or hysterectomies. The literature review found 50% of scar endometriosis cases occurred within a year after surgery.
| Type of Sudden Onset | Key Points from Research |
|---|---|
| Onset after menarche or pregnancy | Symptoms often begin shortly after these events, suggesting abrupt trigger |
| Onset after cervical trauma | Case reports of sudden endometriosis following uterine trauma |
| Rapid onset in animal models | Lesions and symptoms develop quickly after tissue transplantation in animals |
| Sudden spread to surgical scars | 50% of scar endometriosis occurred within 1 year of surgery |
Rare sudden onset with definite cause
There are a few rare situations where the onset of endometriosis truly appears to begin abruptly and can be traced to a definite cause:
– Direct transplantation of endometrial tissue during surgery
– Endometriosis spreading rapidly through vascular/lymphatic channels after trauma
– Sudden spillage of endometrial tissue into pelvis after uterine perforation
However, these accounts are very rare and unusual. Most cases of endometriosis do not have a confirmed sudden, traceable cause.
Challenges investigating onset
There are some challenges when investigating whether endometriosis begins suddenly:
Delay in diagnosis
There is often a years-long delay between symptom onset and diagnosis, making it difficult to pinpoint when it began. Recall bias can affect reports of when symptoms started.
Lack of regular screening
Unlike some diseases, there is no screening for endometriosis in asymptomatic women. It cannot be diagnosed until symptoms appear or surgery done for other reasons.
Individual differences
Each patient likely has a unique disease course. Some may have an abrupt onset, while in others it develops slowly. More research is needed.
No way to predict onset
There are currently no predictive biomarkers or indicators to determine which patients will have a sudden onset of endometriosis.
Conclusion
In summary, the onset and progression of endometriosis is complex and likely varies between individuals. While research suggests endometriosis can theoretically begin suddenly under the right conditions, there is limited evidence that this is common. In many patients, it either develops slowly over time before becoming symptomatic, or it is present asymptomatically for years before something abrupt triggers symptoms. Despite hypotheses from animal models showing endometriosis can onset quickly, it remains challenging to investigate onset patterns in actual patients. More research is needed tracking patients from before diagnosis to look for biomarkers or indicators of sudden onset. In general, the onset of endometriosis cannot be easily predicted, and symptoms may begin gradually or abruptly. Patients should work closely with their doctor to determine the optimal individualized treatment plan for their disease course.