Overview
Definition:
An enterovesical fistula is an abnormal tract connecting the intestinal tract (enteron) to the urinary bladder (vesica)
It results in the abnormal passage of intestinal contents (such as gas or feces) into the bladder, and urine into the intestinal tract
This leads to significant morbidity, including recurrent urinary tract infections, pneumaturia, fecaluria, and sepsis
The most common causes are iatrogenic, due to surgery or radiation, followed by inflammatory bowel disease and malignancy.
Epidemiology:
Enterovesical fistulas are relatively rare, with an incidence that varies depending on the underlying etiology
Post-surgical fistulas account for the majority, particularly after gynecological, colorectal, and urological procedures
Diverticulitis is the most common non-iatrogenic cause, accounting for up to 30% of cases
Malignancy-related fistulas are also significant, often associated with advanced pelvic cancers
The incidence of radiation-induced fistulas has decreased with improved radiotherapy techniques.
Clinical Significance:
Enterovesical fistulas represent a significant challenge in surgical practice due to their complex etiology and potential for severe complications
Early diagnosis and appropriate management are crucial to prevent life-threatening sepsis, improve quality of life by alleviating distressing symptoms like pneumaturia and fecaluria, and optimize patient outcomes
Understanding the different etiologies and surgical approaches is vital for residents preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Recurrent urinary tract infections unresponsive to standard treatment
Pneumaturia (passage of gas bubbles in urine) is a hallmark symptom
Fecaluria (passage of fecal matter in urine) is pathognomonic but less common
Suprapubic pain and discomfort
Bladder irritation symptoms like urgency and frequency
Fever and chills may indicate associated infection or sepsis
Passage of purulent discharge from the urethra.
Signs:
Tenderness in the suprapubic region or lower abdomen
Palpable abdominal mass in cases of associated inflammatory process or malignancy
Signs of systemic infection like fever, tachycardia, and hypotension in severe cases
Digital rectal examination may reveal inflammation or a fistula tract in the perianal area
In women, pelvic examination may reveal signs of inflammation or fistula.
Diagnostic Criteria:
Diagnosis is primarily clinical, supported by investigations
The presence of pneumaturia and/or fecaluria strongly suggests an enterovesical fistula
Recurrent, severe UTIs in the absence of typical risk factors should raise suspicion
While no formal diagnostic criteria exist, the combination of suggestive symptoms and positive imaging findings confirms the diagnosis.
Diagnostic Approach
History Taking:
Detailed history of previous abdominal or pelvic surgery, particularly involving the bowel, bladder, or gynecological organs
History of radiation therapy to the pelvis
History of inflammatory bowel disease (Crohn's disease, ulcerative colitis)
History of pelvic malignancy or its treatment
Onset and progression of symptoms, especially pneumaturia, fecaluria, and recurrent UTIs
Presence of any associated systemic symptoms like fever or weight loss.
Physical Examination:
General examination focusing on signs of systemic illness (fever, dehydration, malnutrition)
Abdominal examination for tenderness, masses, and signs of peritonitis
Digital rectal examination to assess for rectal involvement, inflammation, or tenderness
Pelvic examination in women to assess for gynecological causes or involvement
Examination of the external genitalia for any discharge.
Investigations:
Urinalysis and urine culture to identify infection and assess for fecal contamination
Complete blood count (CBC) to assess for leukocytosis and anemia
Imaging modalities: Cystography with contrast is highly sensitive for detecting fistulas, often showing contrast filling the bowel
CT scan of the abdomen and pelvis with oral and IV contrast is crucial for delineating the fistula tract, identifying the involved bowel segment, and assessing associated inflammatory changes or complications
MRI may be useful in specific cases, particularly for evaluating pelvic anatomy and soft tissues
Colonoscopy or sigmoidoscopy may be indicated to assess for inflammatory bowel disease or colonic pathology
Cystoscopy is essential to visualize the bladder opening of the fistula and assess the bladder mucosa for inflammation or tumor involvement.
Differential Diagnosis:
Severe urinary tract infections with gas-forming organisms (e.g., Klebsiella)
Bladder diverticula
Pelvic abscesses with bladder erosion
Malignancy of the bladder or adjacent organs invading the bladder
Intra-abdominal abscesses with bladder fistulization
Severe inflammatory conditions of the pelvis not involving the bowel or bladder directly.
Management
Initial Management:
Antibiotic therapy to treat or prevent sepsis and recurrent UTIs
Aggressive fluid resuscitation and nutritional support
Management of underlying causes, such as bowel obstruction or perforation, if present
Stoma formation (colostomy or ileostomy) may be necessary for fecal diversion in severe cases or as a temporizing measure.
Medical Management:
Prophylactic antibiotics to prevent recurrent UTIs
Antiemetics and analgesics for symptomatic relief
Nutritional optimization through oral or parenteral routes
Management of inflammatory bowel disease with appropriate medical therapy if it is the underlying cause.
Surgical Management:
Surgical intervention is typically required for definitive treatment
The goals of surgery are to resect the diseased bowel segment, close the fistula, and reconstruct the involved organs
Key surgical steps include: 1
Bowel resection: Excision of the involved segment of the intestine (e.g., colon, small bowel)
2
Fistula closure: Direct closure of the fistula orifice in the bladder and bowel, or creation of a new ostomy
3
Reconstruction: Reconstruction of the gastrointestinal tract (e.g., anastomosis) and urinary tract if necessary
Urinary diversion (e.g., ileal conduit, suprapubic cystostomy) may be required in complex cases or if bladder reconstruction is not feasible
Conservative management with only stoma diversion may be considered in critically ill patients or those with extensive comorbidities, with definitive repair deferred.
Supportive Care:
Close monitoring of vital signs and fluid balance
Aggressive pain management
Strict adherence to antibiotic regimens
Nutritional support, including high-protein, low-residue diet, and parenteral nutrition if indicated
Psychological support for patients experiencing debilitating symptoms and facing major surgery.
Complications
Early Complications:
Sepsis and septic shock from contaminated urine and bowel contents
Anemia due to chronic blood loss or poor nutrition
Wound infection and dehiscence
Anastomotic leak if bowel resection and reanastomosis are performed
Formation of pelvic abscess.
Late Complications:
Recurrent fistulas
Adhesions and bowel obstruction
Strictures at the site of anastomosis or in the urinary tract
Impotence or sexual dysfunction
Psychological distress
Incisional hernias.
Prevention Strategies:
Meticulous surgical technique during pelvic procedures to avoid inadvertent bowel or bladder injury
Careful dissection and identification of anatomy
Prompt recognition and repair of intraoperative injuries
Judicious use of radiation therapy
Early diagnosis and management of inflammatory bowel disease
Careful postoperative monitoring for early signs of complications.
Prognosis
Factors Affecting Prognosis:
The underlying etiology is a major prognostic factor, with iatrogenic fistulas generally having a better prognosis than those due to malignancy or extensive inflammatory disease
The patient's overall health status, presence of comorbidities, and the extent of disease significantly impact outcomes
Timeliness of diagnosis and treatment also plays a critical role.
Outcomes:
With timely and appropriate surgical intervention, the prognosis for enterovesical fistula repair is generally favorable, with high success rates
Symptom resolution (cessation of pneumaturia and fecaluria) is typically achieved
Long-term complications can occur and require ongoing management
Morbidity and mortality rates are higher in patients with severe sepsis, advanced malignancy, or significant comorbidities.
Follow Up:
Regular follow-up is essential to monitor for recurrence, assess for long-term complications such as bowel obstruction or strictures, and manage any residual issues
Follow-up may include clinical assessment, urinalysis, and imaging studies depending on the original etiology and surgical procedure performed
Patients with inflammatory bowel disease require ongoing gastroenterological care.
Key Points
Exam Focus:
Pneumaturia and fecaluria are pathognomonic symptoms
CT scan is the investigation of choice for delineating the fistula
Surgical resection of involved bowel and closure of the fistula is the definitive management
Consider urinary diversion in complex cases.
Clinical Pearls:
Always consider an enterovesical fistula in patients with recurrent, unexplained UTIs, especially if they have a history of pelvic surgery or radiation
Be vigilant for subtle signs of fecal contamination in urine
Multidisciplinary approach involving urology, general surgery, gastroenterology, and radiology is often necessary.
Common Mistakes:
Delaying surgical intervention in favor of conservative management when definitive repair is indicated
Inadequate bowel resection leading to recurrence
Failure to adequately assess and manage associated complications like sepsis or abscess
Misinterpreting imaging findings or missing concomitant pathology.