What could be causing bright red rectal bleeding in a patient with a confirmed rectocele, Ehlers-Danlos Syndrome (EDS), endometriosis, and possible Deep Infiltrating Endometriosis (DIE), who has a history of fallopian tube removal due to adhesion to the bowels and no hemorrhoids?

Potential Causes of Bright Red Rectal Bleeding in This Patient

The most likely cause of bright red rectal bleeding in this patient with endometriosis, possible DIE, and history of bowel adhesions is deep infiltrating endometriosis involving the rectum or rectosigmoid colon, which requires colonoscopy for definitive diagnosis and to exclude other serious pathology. 1, 2

Primary Differential Diagnosis

Deep Infiltrating Endometriosis (DIE) of the Bowel

• DIE frequently affects the digestive tract, particularly the rectum and rectosigmoid junction, and can cause rectal bleeding when endometrial implants penetrate the bowel wall 3, 4
• The patient's history of fallopian tube adhesion to bowels strongly suggests pelvic endometriosis with bowel involvement 3
• DIE is often multifocal and predominantly affects posterior pelvic structures including the rectum 3, 5
• Intramural endometriosis of the rectum is confirmed in 96.7% of surgical specimens when DIE involves the bowel 2
• Clinical examination is notoriously poor at detecting bowel DIE—only 35.3% of patients with digestive tract endometriosis have palpable nodules on routine examination 5

Rectocele-Related Mucosal Trauma

• The confirmed rectocele may cause chronic mucosal trauma from straining or incomplete evacuation, leading to bleeding 1
• However, rectocele alone typically causes bleeding from associated hemorrhoids, which are absent in this patient 1

EDS-Related Vascular Fragility

• Ehlers-Danlos Syndrome, particularly vascular EDS (Type IV), causes tissue fragility and increased bleeding complications 6, 7
• Even in hypermobile EDS, tissue fragility can lead to mucosal bleeding with minimal trauma 6
• Up to 98% of hypermobile EDS patients experience gastrointestinal manifestations 6
• The combination of EDS tissue fragility with DIE may increase bleeding risk 7

Other Critical Diagnoses to Exclude

Inflammatory Bowel Disease

• Colonoscopy with sigmoidoscopy is essential to evaluate for IBD in hemodynamically stable patients with GI bleeding 1
• IBD can coexist with endometriosis and should be excluded 1

Colorectal Cancer or Polyps

• It is extremely important not to blindly attribute painless rectal bleeding to benign causes without full colonoscopy 1
• Colonoscopy is warranted when there is concern for cancer based on patient history or physical examination 1

Diverticular Disease or Angiodysplasia

• These are common causes of lower GI bleeding, particularly in patients over 45 years 1
• Bright red blood typically indicates arterial oxygen tension from arteriovenous communications 1

Recommended Diagnostic Approach

Immediate Assessment

• Assess hemodynamic status and resuscitate if needed, maintaining hemoglobin >7 g/dL (>9 g/dL if massive bleeding or cardiovascular comorbidities) 1
• Nasogastric tube placement if massive bleeding to protect airway and rule out upper GI source 1

Endoscopic Evaluation

• Proceed with colonoscopy as planned to visualize the entire colon and rectum 1
• Consider sigmoidoscopy first if patient is stable, followed by esophagogastroduodenoscopy to exclude upper GI bleeding 1
• Anoscopy should be performed as part of the examination when feasible and well-tolerated 1

Advanced Imaging if Needed

• Consider contrast-enhanced CT before colonoscopy, as it increases detection rate for vascular lesions (35.7% vs 20.6%) 1
• MRI pelvis has 92.4% sensitivity and 94.6% specificity for detecting intestinal endometriosis 1
• MRI is particularly valuable for assessing DIE extent before potential fertility-sparing surgery 1

EDS-Specific Precautions

• If vascular EDS is suspected, avoid invasive vascular imaging due to risk of fatal complications 7, 8
• Use meticulous technique during colonoscopy given tissue fragility 7
• Consider COL3A1 gene mutation testing if vascular EDS features are present (thin translucent skin, easy bruising, characteristic facial features) 6, 8

Critical Clinical Pitfalls to Avoid

• Do not assume bleeding is from rectocele alone when hemorrhoids are absent—this requires full investigation 1
• Do not delay colonoscopy in patients with endometriosis and rectal bleeding—bowel DIE requires definitive diagnosis 2
• Do not perform invasive procedures without considering EDS-related tissue fragility and bleeding risk 7
• Do not attribute all symptoms to one diagnosis—multiple pathologies can coexist (DIE + IBD, DIE + malignancy) 1

Expected Colonoscopy Findings

If DIE is present, colonoscopy may reveal:

• Extrinsic compression of the rectum or sigmoid colon 2
• Mucosal nodularity or irregularity 2
• Stenosis or narrowing of the bowel lumen 2
• Note: Endometriotic lesions may not be visible endoscopically if they are primarily subserosal or intramural 5, 2