Bowel Endometriosis: Causes, Symptoms, Treatment, Diagnosis

Endometriosis is a condition in which the tissue that normally lines the uterus grows in the other parts of the pelvis such as ovaries or fallopian tubes or even tissue lines of the pelvis. This tissue overgrowth acts just like the normal tissue- it swells, breakdown and bleeds every 28 days. As the tissue has no outlet, it gets trapped inside the body leading to scar tissue and adhesions.

In bowel endometriosis, the endometrial tissue grows deeper in the pelvis on the surface or the inside of the intestine. One-third of the women with endometriosis have endometrial tissue in their bowel.⁽¹⁾ Mostly bowel endometriosis occurs in the lower part of the intestine and can also build up in the appendix or small intestine.

Sometimes, bowel endometriosis is a part of rectovaginal endometriosis that affects the vagina and rectum. Most of the females with bowel endometriosis have common sites around the pelvis that include:

• Ovaries
• Bladder
• Pouch of Douglas (the area between the cervix and rectum)

What causes bowel endometriosis is not exactly known. Theories suggest it to be due to retrograde menstruation, in which the menstrual blood flows back through the fallopian tubes into the pelvis instead of going outside the body.

Other causes of Bowel Endometriosis can be:

• Early cell transformation in which the cell leftover from the embryo develop into endometriosis
• Transplantation, in which the endometrial cell travels through the lymph system or blood to other organs of the body
• Genes as endometriosis is sometimes found running in families

Some females do not experience any symptoms and do not come to know that they are suffering from bowel endometriosis.

If symptoms of bowel endometriosis occur, they are similar to irritable bowel syndrome, the only difference being, endometriosis symptoms start around the time of the period. The tissue responds to the hormonal cycle of the period.

The symptoms that are unique to bowel endometriosis are:

• Pain during bowel movement
• Diarrhea
• Constipation
• Abdominal cramps
• Bloating
• Rectal bleeding
• Straining during bowel movements

Females with bowel endometriosis also have endometriosis in the pelvis.⁽²⁾ It can lead to the following symptoms:

• Pain before and during periods
• Pain during sex
• Fatigue
• Heavy bleeding in between periods
• Diarrhea
• Nausea

A pelvic examination is done to check for the growth in the vagina or rectum.

There are a few tests recommended by the doctor to diagnose bowel endometriosis. These include:

Ultrasound High-frequency sound waves are used to create pictures of the inside of the body. In a transvaginal ultrasound, a transducer is placed inside the vagina and in transrectal endoscopic ultrasound it is placed in the rectum.

The ultrasound can show the size of the endometriosis and its location.

• MRI: Powerful magnetic waves and radio waves are used to look for endometriosis in the bowel and other parts of the pelvis.
• Barium Enema: It is done to take pictures of the large intestine i.e. the colon and rectum. During the test, a contrast dye is filled in the rectum to give a better view.
• Colonoscopy: This test help view the inside of the intestine. This test doesn’t diagnose bowel endometriosis but can rule out cancer that can cause similar symptoms.
• Laparoscopy: During this test, a thin, lighted scope is inserted into the belly by making tiny incisions in the belly. It helps in finding endometriosis in the abdomen and pelvis. A doctor might even remove a piece of tissue to examine. The patient is sedated during the process.

Depending on the amount of tissue and how deeply the endometriosis is present in the organs, it is divided into stages:

• Stage1 (Minimal): Small patches of endometriosis are present on or around the organ of the pelvis.
• Stage 2 (Mild): The patches are found to be extensive than in stage 1, but are not inside the pelvic organs.
• Stage 3 (Moderate): In this stage, the endometriosis is more widespread and starts getting inside the pelvic organs.
• Stage 4 (Severe): In this stage, the endometriosis has penetrated most of the organs in the pelvis.

Bowel endometriosis is usually stage 4.

There is no cure for endometriosis but medicine and surgery can help manage the symptoms. The treatment of bowel endometriosis depends on the severity of endometriosis and its location.

If a person is asymptomatic, then treatment for bowel endometriosis may not be required.

This is the main treatment of endometriosis. The removal of the endometrial tissue can ease pain and improve the quality of life.

The surgeries that help in removing bowel endometriosis are:

• Segmental Bowel Resection: It involves removal of the affected part of the intestine and is done for larger areas of endometriosis. The remaining two pieces are reconnected with reanastomosis. The return of the endometriosis after resection is unlikely.
• Rectal Shaving: With the help of a sharp instrument, the surgeon removes the endometriosis of the top of the bowel, without taking out any part of the intestine. This procedure is done for the small areas of endometriosis. There are chances of return of endometriosis after this procedure.
• Disc Resection: For a smaller area a small disc-shaped part is cut out of the affected tissue and then the hole is closed.

Hormone treatments are used for bowel endometriosis. This does not stop endometriosis from occurring but can ease pain and other symptoms.

The medications include:

• Progestin injections
• Birth control pills, patch, and ring
• Gonadotropin-releasing hormone agonist
• Over-the-counter prescription or non-steroidal anti-inflammatory drugs is given to relieve pain.

Endometriosis can affect fertility especially if it is present in the ovaries and other pelvic organs. Half of the females with this condition are unable to conceive.⁽³⁾

The outlook of endometriosis depends on how it’s treated. Symptoms improve once a person goes through menopause.