Can endometriosis cause rectal bleeding?

Endometriosis Can Cause Rectal Bleeding

Yes, endometriosis can cause rectal bleeding, particularly when it infiltrates the muscular bowel wall in the form of rectosigmoid endometriosis. 1, 2 This occurs when endometrial tissue grows outside the uterus and invades the intestinal tract, with the anterior wall of the rectosigmoid colon being the most common location for bowel endometriosis.

Pathophysiology of Rectal Bleeding in Endometriosis

Endometriosis can affect the intestinal tract in several ways:

• The anterior wall of the rectosigmoid colon is the most common location for bowel endometriosis 1
• Other affected areas include the sigmoid colon, cecum, ileocecal valve, appendix, and small bowel 1
• Endometriosis can infiltrate the muscular bowel wall, leading to gastrointestinal symptoms including rectal bleeding 1, 2
• Cyclical rectal bleeding that coincides with menstruation (catamenial rectal bleeding) is particularly suggestive of intestinal endometriosis 3, 4

Diagnosis of Rectosigmoid Endometriosis

Imaging Modalities

1. Transvaginal Ultrasound (TVUS)

   • Can effectively evaluate rectosigmoid endometriosis 1
   • Expanded protocol TVUS studies have excellent performance for detection of deep infiltrating endometriosis 1
   • Cannot evaluate lesions proximal to the rectosigmoid junction 1

2. Transabdominal Ultrasound

   • Cannot directly evaluate rectosigmoid lesions 1
   • Useful as an adjunct to identify bowel involvement beyond the pelvis (appendix, terminal ileum, cecum, sigmoid) 1

3. Transrectal Ultrasound

   • Allows evaluation of bowel wall layers involved by endometriotic lesions 1
   • Helps with surgical planning by determining depth of invasion 1
   • Has shown high sensitivity (97%) and specificity (96%) for detection of rectovaginal endometriosis 1

4. MRI Pelvis

   • Excellent modality to detect and classify rectosigmoid bowel endometriosis 1
   • Provides detailed information on lesion length, thickness, and circumferential involvement 1
   • 92.4% sensitive and 94.6% specific in detecting intestinal endometriosis 1

5. CT Techniques

   • Standard pelvic CT is not recommended 1
   • Specialized CT techniques (with colonic distention by water enema or CT colonography) can be useful but are not widely available 1

Clinical Presentation

Patients with rectosigmoid endometriosis may present with:

• Chronic pelvic pain
• Dysmenorrhea
• Deep dyspareunia
• Dyschezia (painful bowel movements)
• Rectal bleeding, often cyclical with menstruation 2, 3, 5

Management Options

Medical Treatment

• Birth control pills
• Oral progestins
• Gonadotropin-releasing hormone agonists
• Danazol
• Injectable progestins
• Analgesics 2

Surgical Treatment

Rectosigmoid bowel lesions can be removed by:

1. Surgical shaving of superficial rectal lesions 1, 2
2. Laparoscopic anterior discoid resection 2
3. Segmental resection with reanastomosis 1, 2, 6

Surgical approaches include:

• Transvaginal
• Laparoscopic (preferred when possible)
• Laparotomy
• Combined approaches 2, 6

Surgery can improve up to 70% of symptoms but may have complications including intra-abdominal bleeding, anastomotic leaks, rectovaginal fistulas, and strictures 2.

Important Considerations

• Intestinal endometriosis can mimic colorectal cancer by producing an invasive abdominal mass 5
• Cyclic rectal bleeding in women of reproductive age should raise suspicion for intestinal endometriosis 3, 4
• Treatment is best approached collaboratively between gynecologists and intestinal surgeons 4
• Laparoscopic partial bowel resection can be performed with good outcomes but should be done in specialized centers 6

Diagnostic Pitfalls

• Symptoms of intestinal endometriosis significantly overlap with irritable bowel syndrome (IBS), making differentiation difficult 4
• Rectal bleeding in young women may be misattributed to hemorrhoids or other common causes, delaying diagnosis 5
• The interval between onset of symptoms and surgery can range from weeks to years 6
• Standard imaging techniques may miss intestinal endometriosis unless specifically looking for it 1

For patients presenting with rectal bleeding and suspected endometriosis, a specialized transvaginal or transrectal ultrasound performed by a trained operator, followed by MRI if needed, provides the most accurate diagnostic approach.