Loss of bowel control, medically termed fecal incontinence, is the involuntary passage of gas or stool. This symptom ranges in severity from occasional, minor leakage to a complete inability to hold a bowel movement. It is a common medical condition that affects many people. Fecal incontinence occurs when the complex coordination between the rectum, anus, and nervous system is disrupted. Understanding the potential causes can help guide appropriate medical consultation.
Is Loss of Bowel Control Always a Sign of Cancer?
Fecal incontinence is rarely the first or only indication of cancer, though it can occur in cases of colorectal or anal malignancy. Colorectal tumors, especially those located low in the rectum, can physically obstruct the passage of stool. This obstruction can lead to a condition called overflow incontinence, where liquid stool bypasses the solid blockage and leaks out uncontrollably. A tumor can also directly damage the nerves or the sphincter muscles necessary for continence, particularly in the case of anal cancer.
In these cancer-related instances, the incontinence is usually accompanied by other persistent symptoms, which makes it distinct from most benign causes. The vast majority of fecal incontinence cases are attributed to non-cancerous factors, such as injury or chronic digestive disorders. Treatment for certain pelvic cancers, like radiation therapy or surgery, can also result in secondary incontinence due to tissue or nerve damage.
Common Non-Cancerous Causes of Fecal Incontinence
The most frequent causes of accidental bowel leakage involve damage to the muscles or nerves that maintain continence. Muscle damage is often injury sustained during vaginal childbirth, particularly complicated deliveries involving forceps or extensive tears to the perineum. This can damage the anal sphincter muscles, which are responsible for keeping the anus closed. Sphincter damage can also result from prior anorectal surgeries, such as those performed to treat hemorrhoids or anal fistulas.
Damage to the nerves that control the anal sphincter and sense the presence of stool is another common etiology. Chronic conditions like diabetes, multiple sclerosis, or stroke can weaken the nerve signals between the rectum and the brain. When nerve function is impaired, a person may not feel the urge to defecate, leading to passive leakage. Chronic straining from constipation can also cause nerve damage over time.
Disruptions in stool consistency are a frequent contributor to incontinence episodes. Severe diarrhea produces loose, watery stool that is harder for the muscles to contain. Conversely, chronic, severe constipation can lead to fecal impaction, where a hard mass of stool is lodged in the rectum. In these cases, liquid stool leaks around the obstruction, resulting in overflow incontinence.
Other mechanical issues in the anal area can also compromise continence. Rectal prolapse, where the rectum telescopes and protrudes through the anus, interferes with sphincter function. Similarly, large internal hemorrhoids can prevent the anal opening from closing completely, allowing for the passive leakage of mucus or liquid stool.
Accompanying Symptoms That Require Urgent Medical Evaluation
While most cases of accidental bowel leakage are benign, certain co-occurring symptoms should prompt an immediate medical consultation. Persistent, unexplained rectal bleeding is a significant red flag that warrants urgent investigation. This includes bright red blood on the toilet paper or the passage of dark, tarry stools, which can indicate bleeding higher in the digestive tract.
Unexplained, rapid weight loss is another symptom that raises suspicion for a more serious underlying condition, including malignancy. Weight loss that occurs without changes to diet or exercise suggests the body is using energy reserves due to an abnormal process. Severe, persistent abdominal pain or cramping that does not resolve with typical remedies is also concerning.
A sudden, persistent change in the diameter of stool can signal a partial obstruction in the colon or rectum. Any new onset of fecal incontinence coupled with weakness or numbness in the legs may indicate a neurological issue and requires prompt evaluation.
What to Expect During Diagnosis and Treatment
A medical evaluation for fecal incontinence begins with a thorough discussion of symptoms, medical history, and childbirth history for women. A physical examination, including a Digital Rectal Exam (DRE), is typically performed to assess the strength of the anal sphincter muscles and check for masses or prolapse. Based on the initial findings, a doctor may recommend specialized diagnostic tests.
Anorectal manometry is a common test that measures the pressures of the anal sphincter muscles and checks the sensitivity of the rectum. An endoanal ultrasound uses a small probe inserted into the rectum to create images of the anal muscles and detect any structural tears or defects. To rule out more serious causes, a colonoscopy or flexible sigmoidoscopy may be performed to visualize the lining of the colon and rectum.
Initial non-surgical management focuses on conservative strategies to improve stool consistency and muscle strength. Dietary modifications often involve increasing fiber intake through supplements like psyllium or methylcellulose to add bulk and firmness to the stool, making it easier to control. For individuals with diarrhea-related incontinence, anti-diarrheal medications such as loperamide may be prescribed to slow gut motility.
Pelvic floor exercises, often called Kegels, are used to strengthen the external anal sphincter and surrounding muscles. Biofeedback therapy is a specialized training method that uses monitoring devices to help a person learn to correctly identify and contract their pelvic floor muscles. If these conservative measures are not sufficient, other options include sacral nerve stimulation or surgical repair of a damaged sphincter muscle.