What is the appropriate evaluation and management for an 80‑year‑old woman presenting with fecal material leaking from the vagina?

Rectovaginal Fistula: Immediate Evaluation and Management

This 80-year-old woman has a rectovaginal fistula until proven otherwise, and the immediate priority is to confirm the diagnosis with pelvic imaging (MRI or CT with rectal contrast), perform a thorough pelvic examination to identify the fistula location and assess for underlying causes, and determine whether urgent surgical intervention is needed based on the presence of sepsis, abscess, or extensive contamination. 1

Initial Clinical Assessment

Physical Examination Priorities

• Perform a complete pelvic and digital rectal examination to identify the fistula tract location (low vs. high), assess for associated perianal abscesses, evaluate rectal mucosal inflammation, and check for retained foreign bodies (particularly pessaries, which can erode through the vaginal wall into the rectum in elderly women). 1, 2
• Document the presence of systemic signs of infection or sepsis including fever, tachycardia, hypotension, or signs of peritoneal contamination, as these determine the urgency of intervention. 1
• Assess for underlying inflammatory bowel disease (particularly Crohn's disease, which accounts for a significant proportion of rectovaginal fistulas in younger patients, though less common in this age group) by looking for perianal skin tags, anal fissures, or other perianal lesions. 1, 3

Critical History Elements

• Obtain a complete surgical history focusing on prior pelvic surgeries, radiation therapy, obstetric trauma, or recent colorectal procedures, as iatrogenic causes are the most common etiology. 4, 5
• Document pessary use history if applicable, as Gellhorn pessaries can erode through the vaginal wall into the rectum, particularly when not regularly maintained. 2
• Assess for symptoms of inflammatory bowel disease including chronic diarrhea, abdominal pain, weight loss, or extraintestinal manifestations. 1, 3

Diagnostic Imaging Strategy

First-Line Imaging

MRI pelvis is the preferred initial imaging modality for suspected rectovaginal fistula, as it provides superior soft tissue characterization, identifies the fistula tract location and course, detects associated abscesses or fluid collections, and evaluates the integrity of the rectal and vaginal walls. 1, 5

Alternative Imaging Options

• CT pelvis with IV and rectal contrast is an acceptable alternative when MRI is unavailable or contraindicated, with 91% sensitivity and 100% specificity for detecting fistulas when rectal contrast is used. 1
• Water-soluble contrast enema can be performed to visualize the fistula tract and assess for additional complications such as strictures or sinus tracts, though it has lower sensitivity (33.3%) compared to cross-sectional imaging. 1

Imaging Technique Specifications

• For CT imaging: Use IV contrast to evaluate for abscesses and assess bowel wall integrity; administer water-soluble rectal contrast to demonstrate extraluminal extravasation confirming the fistula; avoid barium if perforation is suspected. 1
• For MRI imaging: Use a 3T or 1.5T magnet with appropriate pelvic sequences to visualize the fistula tract, assess sphincter involvement, and identify underlying pathology. 1, 5

Management Algorithm

Step 1: Rule Out Surgical Emergencies

If the patient has signs of sepsis, hemodynamic instability, or peritoneal contamination, immediate surgical consultation is mandatory with consideration for emergent laparotomy and damage control surgery. 1

If imaging reveals a perirectal or pelvic abscess, urgent surgical drainage is required via incision and drainage, with timing based on the severity of sepsis. 1

Step 2: Assess Rectal Mucosal Status

Surgical repair of rectovaginal fistula can only be performed when there is endoscopic healing of the rectosigmoid mucosa. 1

• Perform sigmoidoscopy or colonoscopy to evaluate the rectal mucosa for active inflammation, ulceration, or malignancy. 1, 6
• If active rectal inflammation is present, initiate medical therapy with corticosteroids, immunomodulators (azathioprine, 6-mercaptopurine, methotrexate), or biologic agents (infliximab) to achieve mucosal healing before considering surgical repair. 1

Step 3: Determine Fistula Complexity and Treatment Approach

For Simple, Low Rectovaginal Fistulas (Without Rectal Inflammation)

Surgical repair with transanal or transvaginal advancement flaps is the definitive treatment when the rectosigmoid mucosa is healed and there is no evidence of anorectal stricture or active rectal disease. 1

• Important caveat: Advancement flap surgery should be reserved for patients with disabling symptoms because of the risk of worsening symptoms in those patients in whom the operation fails. 1
• Recurrence rates following endorectal advancement flap procedures are relatively high, so patients should be counseled accordingly. 1

For Complex Fistulas or Crohn's-Related Fistulas

Infliximab is the initial treatment of choice for complex rectovaginal fistulas, particularly in the setting of Crohn's disease, as it can completely close all fistula tracts in many patients. 1

• Coadminister azathioprine, 6-mercaptopurine, or methotrexate routinely both to counteract immunogenic reactions to infliximab and as maintenance therapy. 1
• Some patients will require combination maintenance therapy with both a biologic agent and an immunomodulator. 1
• Alternative agents including tacrolimus or cyclosporine can be considered in patients who fail multimodality therapy, though nephrotoxicity and other side effects occur frequently. 1

Step 4: Consider Conservative Management in Select Cases

Some women may choose to accept residual fistula drainage over proctectomy with an ostomy to optimize their overall quality of life, particularly in elderly patients with significant comorbidities. 1

Nonsurgical management with vaginal estrogen cream has been reported successful in small, iatrogenic fistulas (such as those caused by pessary erosion), though this requires close follow-up. 2

Antibiotic Therapy Considerations

Broad-spectrum antibiotics are indicated if there are signs of sepsis, surrounding soft tissue infection, or in immunocompromised patients. 1

Sample drained pus in high-risk patients or when there are risk factors for multidrug-resistant organisms to guide antibiotic selection. 1

Critical Pitfalls to Avoid

• Do not attempt surgical repair in the presence of active rectal inflammation, as this significantly increases the risk of failure and complications. 1
• Do not overlook pessary-related erosion in elderly women with pelvic organ prolapse, as this is a preventable iatrogenic cause that requires only pessary removal and local wound care in some cases. 2
• Do not perform routine examination under anesthesia (EUA) and seton placement before initiating medical therapy in patients with suspected Crohn's disease, as this is not mandatory. 1
• Recognize that proctectomy with permanent ostomy may be necessary as a last resort in patients with extensive rectal disease, failed multiple repair attempts, or refractory symptoms, but this should be discussed carefully given the profound impact on quality of life in elderly patients. 1