What is a Fistula?
A fistula is an abnormal connection between two body parts, such as an organ or blood vessel and another structure. Fistulas can develop in various parts of the body, but commonly form in the:
- Digestive tract (enterocutaneous fistula)
- Urinary tract (vesicovaginal fistula)
- Vascular system (arteriovenous fistula)
Fistulas create an abnormal passageway for bodily fluids to travel between areas where this flow is not normally found. For example, a vesicovaginal fistula results in urine leaking from the bladder into the vagina.
Many different conditions can cause fistulas to develop, including:
- Injury or trauma
- Surgery
- Infection
- Inflammation
- Radiation treatment
- Congenital abnormality
If the underlying cause can be treated, some fistulas may heal on their own. But many require surgical repair to resolve the abnormal connection.
Signs and Symptoms
Signs and symptoms of a fistula depend on its location in the body.
Digestive Tract Fistulas
Digestive, or enteric, fistulas commonly form between the:
- Stomach and skin (gastrocutaneous fistula)
- Small intestine and skin (enterocutaneous fistula)
- Colon and skin (colocutaneous fistula)
Symptoms may include:
- Drainage of gastric contents, intestinal contents, or feces from an abdominal opening
- Abdominal pain
- Fever
- Infection
- Malnutrition
- Dehydration
Urinary Tract Fistulas
Common urinary tract fistulas include:
- Bladder to vagina (vesicovaginal fistula)
- Ureters to skin (ureterocutaneous fistula)
- Bladder to uterus (vesicouterine fistula)
Symptoms may involve:
- Urine leaking from the vagina
- Inability to control urination
- Recurrent urinary tract infections
- Abdominal or pelvic pain
Vascular Fistulas
Arteriovenous (AV) fistulas commonly form between an artery and vein, often in the extremities. This results in oxygen-rich blood in the artery shunting directly into the vein, bypassing the capillary beds.
Signs and symptoms may include:
- Visible, palpable thrill or pulsation
- Audible bruit (abnormal sound) over the fistula
- Skin changes like redness, warmth, swelling
- Congestive heart failure
- High-output cardiac failure
When is a Fistula an Emergency?
Many fistulas do not cause acute, life-threatening symptoms. But certain types require prompt medical evaluation and treatment.
Emergency fistula situations include:
New Onset of Symptoms
The new onset of fistula symptoms, such as unexplained drainage, urine leakage, or a pulsating mass, requires urgent evaluation to determine the underlying cause. Prompt diagnosis and treatment improves outcomes.
Signs of Infection
Fistulas have a high risk of becoming infected. Signs may include fever, chills, reddened skin, purulent drainage, foul odor, and abdominal pain or tenderness. Septicemia can develop if the infection spreads to the bloodstream.
Uncontrolled Bleeding
While rare, an AV fistula can rupture and cause severe, uncontrolled bleeding. This is a medical emergency requiring immediate treatment to stop blood loss.
Fluid or Electrolyte Imbalances
Intestinal and urinary fistulas can result in substantial fluid losses over time. Evaluation is needed if the patient has signs of dehydration, electrolyte abnormalities, or malnutrition.
Congestive Heart Failure
Large AV fistulas increase the cardiac workload, eventually leading to high-output heart failure. Shortness of breath, fatigue, chest pain, leg swelling, and other heart failure signs require prompt treatment.
Diagnostic Evaluation
If a fistula is suspected, the doctor will perform a full examination, obtain the patient’s history, and order appropriate diagnostic tests. These may include:
Physical Exam
The doctor looks for visible or palpable signs of a fistula, such as drains, masses, bruits, thrills, skin changes, and tenderness.
Imaging Studies
Tests like CT scans, MRIs, ultrasound, or fistulography help visualize the fistula’s anatomy and involvement of surrounding structures.
Endoscopy
A gastroscope or colonoscope inserted through a digestive tract opening can directly visualize some types of fistulas.
Lab Tests
Blood and urine tests check for signs of infection, fluid/electrolyte imbalances, kidney function, and other abnormalities to guide treatment.
Emergency Treatment
Emergency management of serious fistula complications may include:
Fluid Resuscitation
Intravenous fluids help restore blood volume and correct electrolyte abnormalities in dehydrated patients.
Antibiotics
Intravenous, broad-spectrum antibiotics treat any systemic infection related to the fistula.
Wound Care
Drainage and odor is managed by applying dressings over fistula openings.
Surgery
Emergent surgery may be needed to stop active fistula bleeding, divert intestinal contents in life-threatening situations, or close simple vascular fistulas.
Heart Failure Treatment
Medications like diuretics, ACE inhibitors, and beta blockers can temporarily stabilize patients with high-output cardiac failure from AV fistulas.
Definitive Treatment
While conservative measures can temporarily control symptoms, most fistulas ultimately require surgery for definitive repair.
Preoperative Optimization
Prior to fistula surgery, treatment focuses on correcting fluid/electrolyte imbalances, malnutrition, infection, and other medical issues.
Surgical Closure
The main treatment is surgical closure of the abnormal connection. Complex fistulas may require multiple staged procedures.
Bypassing Bowel Segments
Intestinal fistulas are treated by diverting the fecal stream away from the affected area and allowing it to heal.
Angiographic Embolization
Coiling or glue can be injected into blood vessels to block off high-flow vascular fistulas.
Long-term Follow Up
After repair, continued monitoring for recurrence is important, especially for complex fistulas.
Prognosis and Outcomes
The prognosis after fistula treatment depends on:
- Cause – Crohn’s disease fistulas are more likely to recur
- Anatomic location – difficult access makes repair more challenging
- Presence of infection or malnutrition – increase surgical risks
- Degree of tissue damage – extensive scarring reduces healing
With a benign cause and simple anatomy, properly treated fistulas often heal well after corrective surgery. But recurrence rates are high for complex or chronic fistulas.
Even with successful closure, issues like incontinence may persist requiring further treatment. For recalcitrant fistulas, alternative options like glue, plugs, or sclerosing injections may be tried.
Prevention
Certain types of fistulas can be prevented by:
- Careful surgical techniques to avoid injury to adjacent structures
- Meticulous hemostasis to prevent bleeding complications
- Omental flaps or other barriers between operative sites
- Avoiding unintentional bladder/ureter injury during gynecologic surgery
- Timely treatment of obstructed labor,infected abortions, or uterine rupture
- Aggressive management of conditions like Crohn’s disease or diverticulitis
However, fistulas may still occur despite proper precautions due to individual patient factors.
Conclusion
While many fistulas can be treated electively, certain circumstances like new onset of symptoms, bleeding, sepsis, fluid/electrolyte imbalances, or heart failure may require emergency management.
Prompt diagnosis helps identify high-risk situations needing urgent intervention versus more stable cases where definitive surgery can be scheduled.
With appropriate emergency and surgical treatment, outcomes for simple fistulas are often good. However, complex, recurrent, or chronic fistulas may continue to cause significant morbidity requiring multidisciplinary care.