Bowel endometriosis

Understanding the Pain and Symptoms of Bowel Endometriosis

Endometriosis is a condition affecting roughly 11% of women worldwide, predominantly those of reproductive age. An even more specific form of this ailment is bowel endometriosis, which impacts around 5% to 12% of those diagnosed with endometriosis. In this comprehensive guide, we delve into the intricacies of bowel endometriosis, exploring what it feels like, the symptoms, causes, diagnosis, and treatment options.

What is Bowel Endometriosis?

Bowel endometriosis occurs when endometrial-like tissue, which typically grows inside the uterus, begins to develop on or inside the bowel walls. This can lead to a range of gastrointestinal symptoms, often causing significant discomfort and negatively impacting the quality of life.

Read More: Understanding Bowel Endometriosis

Where Does Bowel Endometriosis Occur?

The condition predominantly affects the rectum and sigmoid colon, with approximately 90% of bowel endometriosis cases directly involving these regions. However, the appendix, small intestine, stomach, and other parts of the large intestine can also be affected.  In many cases, bowel symptoms occur because of the mere presence of intensely inflammatory endo lesions on the peritoneum in the pelvis and abdomen and not even involving the bowel directly with implants. 

Symptoms of Bowel Endometriosis

The symptoms of bowel endometriosis often mimic common gastrointestinal disorders, including small intestinal bacterial overgrowth (SIBO), making it difficult to diagnose. They can range from mild to severe, and often fluctuate depending on the menstrual cycle. 

Common Symptoms

Common symptoms may include:

  • Abdominal pain, particularly in the lower quadrants
  • Bloating, often referred to as “endo belly”
  • Changes in bowel movements, including constipation or diarrhea
  • Nausea and vomiting
  • Pain during bowel movements, which might increase during menstruation
  • Rectal bleeding

Non-Bowel Symptoms

In addition to bowel symptoms, individuals with endometriosis might experience:

  • Chronic pelvic pain
  • Difficulties with fertility
  • Painful sexual intercourse
  • Pain during urination
  • Pelvic heaviness
  • Fatigue
  • Impaired psychological well-being

Causes of Bowel Endometriosis

The exact cause of bowel endometriosis remains unknown. However, Mullerianosis of embryogenic origin and retrograde menstruation are two often-quoted theories. Mullerianosis of embryogenic origin suggests that developmental abnormalities lead to cells being present in atypical locations which later turn into endometriosis.  This includes potential genetic, genomic and immunologic influencing factors.  Retrograde menstruation proposes that period blood flows upward towards the Fallopian tubes and into the pelvis instead of out through the vagina, potentially leading to endometriosis. Given that most women experience retrograde menstruation, and only 10% or so experience endometriosis, this theory is antiquated and has been challenged because of this disconnect.  Far more likely, some combination of embryologic, molecular, immunologic and genetic factors are in play and this can vary between individuals.  

Read More: Can Endometriosis Cause Bowel Issues?

Diagnosis of Bowel Endometriosis

Diagnosing bowel endometriosis is a complex process. It often requires a combination of a good evaluation of symptoms history, physical examination, imaging techniques like ultrasound or MRI, and sometimes minimally invasive laparoscopic or robotic surgery. However, diagnosis could be delayed due to its symptom similarity with other gastrointestinal diseases.  Imaging can only help with diagnosis and potential mapping for surgery.  It is absolutely not reliable enough to exclude the diagnosis of endo


Misdiagnosis is common in bowel endometriosis, with many patients being misdiagnosed with irritable bowel syndrome (IBS) or other gastrointestinal disorders. Therefore, a high index of suspicion is necessary for diagnosis, and any bowel symptoms correlated with the menstrual cycle should be critically evaluated.

The Role of Minimally Invasive Surgery

Surgery with biopsy is considered the “gold standard” in diagnosing endometriosis, including bowel endometriosis. It provides a more accurate diagnosis and gives healthcare providers an exact idea of how much scar tissue and endometrial-like tissue they’re dealing with. Ideally, the surgeon should be prepared to perform a therapeutic surgery at the same time as a diagnosis.  However, a bad surgery is worse than no surgery if the surgeon is unprepared and performs some variation of fulguration (burning) of endometriosis lesions as opposed to proper excision of the lesions or implants.  If diagnostic surgery uncovers a situation where the surgeon is unprepared to properly perform therapeutic excision it is better to back out and refer to an appropriate surgeon. 

Treatment of Bowel Endometriosis

Treatment for bowel endometriosis often involves surgery, as medical management has generally been deemed ineffective for these specific lesions. The chosen surgical method depends on the extent of the condition. In many cases, hormonal options may also be recommended after surgery to reduce recurrence risk.  The better the surgery the less likely this would be required but there are exceptions.   

Surgical Treatment

The surgical treatment of endo usually involves removing all of the peritoneal lesions by an excisional technique. In deeply infiltrating endometriosis, the approach may vary based on the involvement of the rectal wall or the mesentery, which is where the blood vessels to the rectum are located. The treatments for bowel endometriosis include shaving, nodulectomy, disc resection, and bowel resection.  The surgeon should be capable of performing any of these procedures as needed at the time.  In some cases this may be the main excision surgeon, if they have bowel surgery training and hospital prvileges, and in other cases, this may be another surgeon who is part of the backup team.   In the latter situation, it is best if the possibility of bowel surgery and options are addressed before surgery and not as an emergency during surgery, when appropriate surgeons may not be readily available.  

Lifestyle Changes

Alongside medical treatment, lifestyle changes can aid in managing bowel endometriosis symptoms. Some patients find that certain foods or lifestyle habits, such as stress or irregular sleep, may trigger their symptoms. Keeping a journal to track triggers and consulting with a healthcare provider or nutritionist when making dietary changes can be beneficial.

Read More: How to Treat Bowel Endometriosis: A Comprehensive Guide

Coping with Bowel Endometriosis

Living with bowel endometriosis can be challenging, but with the right diagnosis, treatment, and management, individuals can lead fulfilling lives. It’s essential to communicate openly with healthcare providers about symptoms and concerns, as this can aid in diagnosis and treatment planning.

In conclusion, bowel endometriosis is a painful and often misunderstood condition. Increased awareness and understanding of the disease can help in early diagnosis, effective treatment, and improved quality of life for those affected. If you suspect you might have bowel endometriosis or are experiencing any of the symptoms mentioned, do not hesitate to seek medical advice.


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