A rectal ulcer is a break or open sore that develops on the mucosal lining of the rectum, the final few inches of the large intestine before the anus. These lesions are frequently associated with a condition known as Solitary Rectal Ulcer Syndrome (SRUS), although they are not always singular. While most rectal ulcers are noncancerous, they represent an injury to the delicate tissue that necessitates medical evaluation. The presence of a sore in this area can interfere with the normal storage and passage of stool, leading to a variety of uncomfortable symptoms.
Recognizing the Signs
Symptoms of a rectal ulcer often involve several distinct signs related to irritation of the rectal lining and changes in bowel function. One of the most common signs is bright red blood when passing stool, caused by the ulcer surface being disrupted during defecation. Patients also frequently notice an excessive discharge of mucus alongside or independent of a bowel movement.
A persistent sensation known as tenesmus is another frequent complaint, described as the feeling of constantly needing to empty the bowels, even when the rectum is empty. This is often accompanied by the feeling of incomplete evacuation, where one struggles to pass stool despite effort and straining. Individuals may also report discomfort or a feeling of fullness and pressure within the pelvis or rectum itself.
Primary Causes of Rectal Ulcers
The majority of non-inflammatory rectal ulcers are linked to Solitary Rectal Ulcer Syndrome, a mechanical disorder resulting from trauma to the rectal wall. The underlying mechanism involves chronic, excessive straining during defecation, often due to long-term constipation or obstructed bowel movements. This prolonged straining can cause the rectal lining to become temporarily pushed down or prolapsed into the anal canal.
This mechanical stress, known as internal intussusception or mucosal prolapse, leads to the rectal wall compressing against the contracting pelvic floor muscles. The resulting friction, coupled with reduced blood flow (ischemia), damages the mucosa and creates the ulceration. Histological examination often shows a characteristic pattern of smooth muscle fibers extending abnormally into the lamina propria, which is a specific marker for SRUS.
A related factor is dyssynergic defecation, also called anismus, where the puborectalis muscle fails to relax properly during defecation attempts. Instead, the muscle contracts paradoxically, increasing pressure in the rectum and contributing to the trauma. Less common causes of rectal ulcers include certain infections, such as those caused by herpes or cytomegalovirus, and inflammatory conditions like inflammatory bowel disease.
Diagnosis and Treatment Approaches
The evaluation process for a suspected rectal ulcer begins with a physical examination, including a digital rectal exam, to check for masses, tenderness, or prolapse. The most direct diagnostic tool is a flexible sigmoidoscopy, where a thin, lighted tube is inserted to visualize the ulcer and the surrounding rectal tissue. This procedure allows the clinician to determine the ulcer’s size, location, and appearance, helping to distinguish it from other conditions.
During the endoscopy, a small tissue sample, or biopsy, is typically taken from the edge of the lesion for laboratory analysis. Histological examination confirms the diagnosis of SRUS by looking for specific tissue changes. To evaluate the functional component of defecation, a test called anorectal manometry may be performed, which measures the pressure and coordination of the rectal and anal muscles.
Conservative Management
Initial treatment, particularly for SRUS, focuses on conservative and behavioral modifications to address the root cause of straining. Patients are advised to adopt a high-fiber diet and use stool softeners or bulking agents to ensure softer, easier-to-pass stools. Avoiding excessive straining during bowel movements is a fundamental step in allowing the ulcer to heal.
Specialized Therapies and Surgery
A specialized form of physical therapy called biofeedback training is highly effective for individuals with dyssynergic defecation. This technique teaches patients to consciously relax their pelvic floor muscles during defecation, correcting the paradoxical muscle contraction that contributes to the trauma. For ulcers that do not respond to lifestyle changes, medical treatments may involve topical agents such as sucralfate enemas, which create a protective layer over the ulcer to promote healing.
Surgical intervention is generally reserved for severe cases where conservative measures have failed or when the ulcer is secondary to significant rectal prolapse. Procedures like rectopexy can be performed to secure the rectum in its correct position and eliminate the mechanical trauma causing the ulceration. In extremely rare instances involving intractable pain and bleeding, a proctectomy (removal of the rectum) may be considered, sometimes necessitating a diverting colostomy.