A fistula is an abnormal, tunnel-like connection that forms between two organs, vessels, or cavities that do not typically connect, often resulting in an abnormal flow of fluid. These passages can develop between the intestine and the skin (enterocutaneous fistula) or between the rectum and the skin near the anus (anal fistula). The formation of a fistula is usually the result of an infection, inflammation, or injury, such as those related to Crohn’s disease or complications from surgery. While some fistulas are intentionally created by surgeons for medical procedures, the vast majority of naturally occurring fistulas require medical attention.
Why Intervention is Generally Required
Fistulas rarely resolve on their own because the abnormal tract maintains an open channel that resists natural closure. This happens primarily due to a process called epithelialization, where the body lines the internal tunnel with skin or mucosal cells. This cellular lining prevents the tissue walls of the tract from fusing and healing shut, effectively stabilizing the abnormal connection. The chronic flow of fluid, pus, or stool through the tunnel further irritates the tract, inhibiting the body’s natural regenerative processes.
An acute, or newly formed, fistula may occasionally close spontaneously, but chronic, established fistulas are nearly always permanent without intervention. Over time, scar tissue develops around the tract, reinforcing the abnormal passage and making closure more difficult. The presence of a persistent internal opening or an underlying condition, such as active inflammation from Crohn’s disease, also ensures the fistula remains open.
Since the body cannot eliminate the underlying cause or the epithelial lining, the fistula becomes a chronic drain or source of infection. Therefore, treatment is generally necessary to close the passage or, at a minimum, to manage the persistent drainage and infection.
Non-Surgical Approaches and When They Apply
Non-surgical methods are frequently used to manage symptoms or attempt closure, especially when traditional surgery poses a high risk to surrounding structures, such as the anal sphincter muscles. Pharmacological treatments are a cornerstone of managing fistulas related to inflammatory conditions like Crohn’s disease. Immunosuppressant drugs and biologic agents, such as adalimumab, are used to reduce systemic inflammation and promote healing of the internal tract.
Antibiotics, such as metronidazole, are often prescribed to control bacterial infection and drainage, but they rarely achieve definitive closure alone. Their primary function is to reduce the bacterial load and inflammation, making the environment more conducive to subsequent healing attempts. For certain simple fistulas, the tract may be filled with a biological compound to encourage scar tissue formation and closure.
Fibrin glue, a biological sealant, can be injected into the cleaned-out tract to obliterate the space and facilitate healing. While this method is minimally invasive and preserves sphincter function, success rates vary significantly, sometimes achieving only a 50% cure rate for complex fistulas. Another non-surgical option is the placement of an anal fistula plug, an absorbable, cone-shaped device inserted to physically block the passage and provide a scaffold for tissue growth.
For complex or actively infected fistulas, a seton is often employed as a temporary measure to manage the condition. A seton is a thin, non-absorbable thread or rubber band placed through the entire tract to allow continuous drainage of pus and fluid. This prevents the build-up of an abscess and stabilizes the tissue. Setons are typically used as a drainage measure to prepare the tract for a later, more definitive surgical procedure.
Dangers of Ignoring an Untreated Fistula
Leaving a fistula untreated allows the underlying infection and inflammation to progress, leading to increasingly severe health consequences. A major risk is the continuous formation of abscesses, which are painful collections of pus that cause swelling and fever. Recurrent abscess formation causes more tissue damage and necessitates emergency drainage, further complicating any future repair.
The chronic infection can spread into the bloodstream, a life-threatening condition known as sepsis. Sepsis requires immediate medical intervention and can lead to organ failure if not treated promptly. Furthermore, an untreated fistula tract can grow and branch over time, turning a simple passage into a complex network of tunnels with multiple external openings.
The development of these complex tracts makes eventual surgical repair more challenging and increases the risk of damage to surrounding muscle tissue. In the anal region, this can damage the anal sphincter muscles, leading to long-term fecal incontinence. The constant discharge and hygiene issues also severely impact quality of life, causing chronic pain, skin irritation, and social isolation.